Hopefully, everyone knows by now that you should wash your hands after you go to the bathroom, before you prepare food, before you eat, after you handle raw meat, when you get home from work, school, or any public place, when you come in from playing outside, after changing diapers, and after handling certain pets or farm animals. Most people also like to use hand sanitizer if they are in a situation where they can't wash their hands. However, I wanted to know how well hand washing and hand sanitizers really work to remove germs.
In case you don't want to read this entire mile long page, here is a summary. I recommend Zylast , Clorox Hand Sanitizer BioProtect, or Germstar Noro because these are the hand sanitizers that are available in the US that have been tested and shown to kill a norovirus surrogate. I see no sense in using a hand sanitizer at all if it isn't going to kill the dreaded stomach bugs. Of those, My 2 favorites are Zylast antiseptic and GFS BioProtect because they both work well on dirt-covered hands. You can order Clorox Hand Sanitizer, Germstar Noro, and Zylast on amazon. You can also order Zylast antiseptic from http://www.zylastdirect.com/catalog.php and use coupon code "StopNorovirus" to receive 10% off your order (That code only works on the Zylast direct website, not on amazon). GFS BioProtect is only available from the companies website. I also provide more information about these hand sanitizers on another page specifically discussing hand sanitizers that kill norovirus.
Here are the products that I have tested so far. Click on a product name in the blue box below to jump to that section.
The Thieves Hand Sanitizer Experimental Results are on the Essential Oils page instead of this page.
If you are new to my website, let me tell you a little about myself. My name is Annie Pryor. I have a Ph.D. in biochemistry from The Ohio State University. After a few years working in a research lab, I "retired" to be a stay-at-home mom. When my first baby got a terrible stomach virus that required a trip to the ER, I decided to research the subject and created this website dedicated to reducing the prevalence of the stomach "flu" in the world. My 3 little kids keep me busy, but I still get a hankering to do experiments now and then. I've tested cleaning products, hand sanitizers, produce washing techniques, essential oils, Norwex Cloths, SteriPens, laundry, lunch box coldness, the Phone Soap, sponges, and even sunlight. I also happen to be the inventor of a really useful drying rack. I invented it because I needed a convenient place next to the kitchen sink to hang baby bibs up to dry between meals. It is also perfect for drying sports water bottles, dish cloths, food-storage bags, cleaning cloths and many other items. I have a shorter drying rack (12.5 inches tall) and a taller 15 inch rack. The Mommy Genius® Drying Racks are manufactured in the USA and are available on Amazon. If you would like to be informed when new experimental results are posted, please like my Facebook page.
Princess Katie and the Fairy Tea Party and Princess Katie and the Mermaid Lagoon are available on amazon. The stories are so sweet and teach about kindness, forgiveness, and including others. I think every little girl would love them! Please consider buying them for a little girl that you love. Katie gets about a $2 royalty from amazon for each book sold that is getting deposited into her college savings account.
Many people are confused and think that I want to kill all the germs in the world. This is not true. There is good bacteria in our bodies and our environment that is extremely important. I consider myself a "norophobe" and not a "germaphobe". I mainly detest stomach viruses and anything that will kill you. I also detest toxic chemicals. So, I don't want to waste my time using a toxic cleaning product that isn't really doing anything or isn't necessary. That is why I wanted to test these products and figure out what is best. So, I don't think you need to sterilize your entire house. It would be impossible anyway. Our bodies, produce, carpet, floors, clothing, and environment are full of germs. Most of them are harmless or even helpful. My kids come inside covered in dirt every day and snuggle with our dog. Everyone gets PLENTY of germ exposure. If you have ever taken a toddler outside to play, you know that they get dirt in their mouths, and it is pretty much impossible to keep them "too clean". However, from my schooling and research I have learned that most nasty illnesses are spread through poop. So, I see no harm in having a clean toilet and washing hands before eating. Washing your hands before eating, keeping a relatively sterile toilet and food preparation surfaces is not going to make a dent in the total number of germs that you are exposed to every day. It will just reduce the likelihood of you coming in contact with a terrible germ.
These experiments involve growing bacteria in petri dishes. The petri dishes have a layer of LB-agar growth medium at the bottom and are frequently called "agar plates". LB-agar is like firm jello and provides food, water, and a nice surface for bacteria, yeast and mold to grow on. I used to make agar plates all the time when I worked in the research lab. For these experiments, I bought them on amazon from Ez BioResearch LLC. (The plates were great and I highly recommend them for anyone doing a Science Fair Project.)
It is important to understand that VIRUSES don't grow on these plates. Viruses only multiply inside another cell (like a human cell). None of the experiments that I have done are looking at viruses. However, if a particular hand sanitizer or hand washing technique does not work to get rid of bacteria, then it probably doesn't work for viruses either (especially the difficult to kill norovirus).
When a single LIVE bacterium is placed on an agar plate and put in a warm place (preferably near body temperature, 98.6 degrees F), it will multiply. It will double, and double again, and double again, and double again until you can SEE a small white pile of bacteria called a colony. It usually takes 12-24 hours of incubation at a warm temperature to see the colony. So, when you are looking at these plates of bacteria, look for the number of colonies on the plates and also how big the colonies are to estimate the amount of bacteria. IF the bacteria are DEAD because a hand sanitizer killed them, they will NOT GROW on the agar plates. You will also see some wispy white stuff on some plates. That is fungus.
I constructed an "incubator" by attaching a clamp lamp with a "Critter Culture Night Heat Bulb" to a plastic box. I added some aluminum foil around it to keep heat inside and keep it at the temperature that I wanted. All through these experiments, the temperature in the incubator was about 90-95 degrees F. I kept a thermometer in the incubator at all times to monitor the temperature.
In case you are doing experiments yourself, it is important to ALWAYS put the plates in the incubator UPSIDE DOWN. The agar layer should be on top so the bacteria grow upside down. This is important because lots of condensation will form and fall to the bottom of the plate. You need to keep the bacteria growing at the top of the plate so they don't get flooded.
For each of these experiments we did a "negative control". This is an LB agar plate that is not supposed to grow anything. It is important to have a "negative control" to make sure you don't have a contamination problem somewhere. For the negative control, we opened the lid of the plate and "pretended" to put our hand in the plate but held our hands 2 inches above the plate. This is to insure that nothing else we were doing in the experiments were contaminating the plates.
Here is a picture of my daughter, Katie Scarlett, pressing her fingers onto the agar plate for one of the experiments. Only the 4 fingers, finger tips, and thumb tip touch the plate. The palms of the hands don't fit in and aren't part of these experiments. Sometimes the kids press a little too hard and tear the agar. This does not hurt the results of the experiment.
, IF you scrub vigorously.
My 8 year old son helped me determine how effective regular hand washing is at removing bacteria. One day right after school, Jon pressed his unclean left hand into a sterile agar plate. Then he did his best hand washing ever. He used Dial Naturals Tangerine and Guava hand soap. He wet his hands in warm water and got 2 squirts of soap. Then he lathered and rubbed vigorously for 30 seconds. Then he rinsed and rubbed for 30 seconds under warm water. He did not touch the faucet to turn the water off and dried his hands on clean paper towel. Then he pressed his clean right hand onto an agar plate. The results show that all of the bacteria were not removed but the hand washing made a significant improvement.
My 5 year old daughter, Katie Scarlett, also did the same experiment. She pressed her dirty left hand onto an agar plate. Then she did her best hand washing ever. She wet her hands in warm water and got 2 squirts of the same soap. She lathered outside of the water stream for 30 seconds. Her lathering was much gentler than my son's. She made lots of bubbles but was not rubbing hard like he was. Then she rinsed her hands for 30 seconds under the running water. She did not touch the faucet or anything and dried her hands on clean paper towel. Then she pressed her fingers into the agar plate. There was still a lot of bacteria on her hand.
I repeated this experiment a different day using the pink Dawn dish soap with Olay Hand Renewal. Again both kids lathered outside of the water for 30 seconds, rinsed for 30 seconds, and dried with clean paper towel. Jon, being 8 years old, did a better job than his 5 year old sister.
I have repeated these hand washing experiments with blue Dawn Ultra Dish soap as well. All of the results look similar.
I did those first hand washing experiments a few years ago. Here are some more recent hand washing experiments with blue dawn ultra.
Here is my very best attempt at hand washing. I had actual dirt from outside on my hands. First, I rubbed my hands onto an agar plate as the dirty control. Then I washed with blue Dawn Ultra for 1.5 minutes. I really lathered, rubbed, and rinsed well. I dried with clean paper towel. Then I rubbed my clean hands onto another agar plate. This is as clean I could get my hands from hand washing.
I am planning to test different hand soaps to see if any work better than others. However, from these experiments, I have learned that there is still a lot bacteria on the skin even after a thorough hand washing. I do not get the super "clean" results that you will see with most of the hand sanitizers. Why is that? I think it is because our skin is full of good/harmless bacteria that naturally live in it. Some are deep in your skin and are not easily removed by hand washing. However, some bacteria still transfer from your hand to an agar plate. So, my guess is that the bacteria that remain on hands after a thorough hand washing, are the harmless bacteria from within our skin. We can only hope that all of the bad germs and viruses that we picked up during the day were washed down the drain during the thorough hand washing. However, some bacteria, such as staph, that are harmless living in our skin, can make people sick if allowed to grow in food. This is why that food service workers should always wear disposable gloves and change those gloves frequently. Their hands will never be clean enough to handle chicken salad no matter how good they wash their hands. If some staph bacteria get into the chicken salad or casserole, they can multiply and produce toxins. Then most people who eat it will be vomiting within 7 hours.
Does the alcohol hand sanitizer, Clorox Hand Sanitizer spray, really kill all of the germs?
For this experiment, we tested Clorox Bleach-Free Hand Sanitizer spray which is 71% ethanol. I like it because it claims to kill norovirus. After preschool, Katie Scarlett pressed her unclean left hand into the agar plate. (Her hands were not visibly dirty.) Then we sprayed both hands with lots of Clorox Bleach-Free Hand Sanitizer spray. I used 10 sprays on each hand, and her hands were soaked and dripping. She rubbed them together until they were dry. Then she pressed her right hand into a sterile agar plate. After incubating for 24 hours, only 1 colony of bacteria was visible on the plate with the sprayed hand. The Clorox Bleach-Free Hand Sanitizer spray did an excellent job of killing the bacteria on her hands.
I also tested Clorox Bleach-Free Hand Sanitizer spray on my father when he stopped by to visit. It worked great but there were a few tiny colonies left on one fingertip. This shows that it is very important to use plenty of spray and to get it everywhere. Alcohol sprays work well on "clean hands" but don't work well on dirty or soiled hands as you can see in the next experiment.
How well does Germstar Noro work?
Germstar Noro is another alcohol hand sanitizer spray. It is specifically designed to kill norovirus and is 63% ethanol. For this experiment, I tested my son's hands after school and my husband's hands after work. They each pressed one "dirty" (but visibly clean) hand into the agar plate. Then I sprayed about 15 sprays of Germstar Noro on their other hand. I rubbed it in myself and let it dry for 1 minute. Then their pressed their Germstar Noro treated hand onto another plate. The results show that Germstar Noro kills bacteria approximately as well as Clorox Hand Sanitizer Spray.
Burt's Bees Aloe & Witch Hazel Hand Sanitizer is an alcohol spray that contains 62% ethanol. It is an all natural hand sanitizer. I tested this alcohol spray on my son's hands after school. Jon pressed a "dirty" (although visibly clean) hand onto one agar plate. Then I sprayed 15 sprays of Burt's Bees Hand Sanitizer with Aloe on his other hand and rubbed it in. He held his hand up in the air for 2 minutes until it dried. Then he pressed his treated hand onto another agar plate. The Burt's Bees Hand Sanitizer seems to work about as well as the other alcohol sprays that I have tested. Just like the rest, you have to use tons of spray if you want to kill most of the bacteria. Burt's Bees Hand Sanitizer has not been tested or its ability to kill norovirus, though.
In the previous experiments, I sprayed about 20 sprays of hand sanitizers on each hand. The hands were dripping wet and fully covered. But no one REALLY does that. People would put 2 sprays on one palm and then rub the hands together. So, I tested this. After school, my son Jon pressed one dirty hand into an agar plate. Then I sprayed only 2 sprays of Clorox Hand Sanitizer on his other hand. I rubbed it in with one of my hands. As you can see, it really didn't do anything. The bottom line is that you need to use A LOT of hand sanitizer to fully cover your hands if you want to actually kill most of the germs.
Does alcohol hand sanitizer spray work when your hands are visibly dirty?
After school, Jon came home with visibly dirty hands from playing on the playground. There was a light layer of dirt on his hands. He pressed his dirty left hand into the agar plate. Then we sprayed both hands with tons of Clorox Bleach-Free Hand Sanitizer Spray. I have never used this much spray. Jon rubbed and rubbed his hands until they were dry. His hands looked a little cleaner but were still dirty. He pressed his "clean" right hand into a sterile agar plate. After 20 hours of incubation, both plates grew approximately equal amounts of bacteria. So, Clorox Hand Sanitizer Spray (and most likely all alcohol sprays) don't work if your hands are soiled.
My husband helped me out with this experiment. After work, he pressed his dirty left hand onto an agar plate. I rubbed a large glob of regular Purell (with moisturizers and Vitamin E) all over his right hand. (His hands were visibly clean.) He held his hand up in the air for a minute to dry and then pressed it into another plate. The Purell worked as good as the alcohol spray and just left 4 small colonies. I have done these experiments multiple times. There may be a few colonies on the sanitized hand whether using the spray or the gel if you miss a spot. It is very important to use lots of the sanitizer. Hand sanitizer gels like Purell not been shown to kill norovirus. I have a list of hand sanitizers that do kill norovirus on this page.
How well does regular Purell Hand Sanitizing Gel work on dirty hands?
To test how well Purell hand sanitizing gel works on visibly dirty hands, I tested my son Jon's hands after he had gotten them dirty in mud outside. He pressed his dirty right hand onto an agar plate. Then I rubbed a quarter sized drop of Purell all over his other hand. It did not appear to remove any dirt. We let his hand dry for 1 minute. Then he pressed the treated hand onto another plate. There seems to be a slight improvement in the amount of bacteria on the treated hand but it is still very dirty.
I tested Purell Advanced (70% ethanol) on dirty hands as well. These were not visibly dirty but the kids had been playing outside with rocks for an hour. So, there was a light coating of dust/dirt. As you can see, the plain alcohol hand sanitizers cannot penetrate actual dirt. So, if you are at a park or on a picnic, wipe hands clean with a wipe and then use the hand sanitizer.
I repeated the same experiment with Bath & Body Works sanitizing hand gel which is 68% alcohol. It did about as good as the rest of the alcohol hand sanitizers. My experiments are not sensitive enough to pick up minor differences. However, this hand sanitizer probably doesn't kill norovirus.
For this experiment, I wiped my son Jon's left hand well with one Wet Ones Antibacterial Wipe. He let his hand dry for 1 minute without touching anything. Then he pressed his fingers and thumb onto the agar plate. His right, "dirty" hand was pressed onto another plate. Both of his hands were visibly clean. The Wet Ones Antibacterial Wipes did a great job killing bacteria. Remember, Wet Ones Antibacterial Wipes probably do not kill norovirus. The active ingredient, benzethonium chloride, has recently been tested for its ability to kill norovirus and it FAILED1.
Germ-X Foaming Hand Sanitizer is an alcohol free hand sanitizer with the active ingredient is .13% Benzalkonium chloride. Germ-X Foaming Hand Sanitizer DOES NOT claim to kill norovirus. I tested this hand sanitizer on my son and daughter after school. The kids pressed their dirty right hand into the plate. Then we rubbed 3 pumps of Germ-X foam onto their left hand, let it dry for 1 minute, and pressed that hand into another plate. It worked really well killing bacteria and fungus. It feels so good on your hands and does not sting like alcohol sanitizers.
How well goes Germ-X Foaming Hand Sanitizer work on dirty hands?
In order to determine how well Germ-X foaming hand sanitizer kills germs on dirty hands, I tested my daughter's hands after she had gotten them dirty outside. She pressed her dirty right hand onto an agar plate. Then I rubbed 3 pumps of Germ-X foam on her left hand. The mud came dripping off. If I had wiped her hand with a dry towel, her hand would have been very clean. I left the mud to dry on her hand for this test, though, because I wanted to see if the bacteria in the mud were being killed. After her hand was dry, she pressed her treated left hand onto a plate. As you can see, Germ-X foaming hand sanitizer works great on muddy hands! This is a great sanitizer to take on picnics or to the playground! It has not been tested and shown to kill norovirus, though, so I don't rely on it.
Pampers Kandoo Foaming Hand Sanitizer is alcohol free and has the active ingredient is .13% benzalkonium chloride. After school, my children pressed one dirty hand onto an agar plate. Then I rubbed 3 pumps of Kandoo Foaming Hand Sanitizer onto their other hand and let it dry. Then they pressed the treated hand onto an agar plate. After 24 hours of incubation, the plates show that Kandoo does a great job killing bacteria. It has not been shown to kill norovirus, though.
CleanWell All-Natural Foaming Hand Sanitizer is alcohol free and does not contain benzalkonium chloride. Its active ingredient is Thymus Vulgaris oil (Thymol .05%). It smells VERY STRONGLY of thyme. After school, my children pressed one dirty (but visibly clean) hand onto an agar plate. I put 3 pumps of Clean Well All-Natural foaming hand sanitizer on the other hand. I rubbed it in and let it dry for 2 minutes (while I held their hand up in the air so they didn't touch anything). Then they pressed their treated hand onto another agar plate. After a 24 hour incubation, the plates show that the CleanWell All Natural Foaming Hand Sanitizer did not seem to kill much of anything. However, the CleanWell company assures me that the product really does work. They say that it only kills the bad bacteria, not the good bacteria that normally resides in your skin. I can't prove that and it has not been shown to kill norovirus.
Qore-24TM is a very exciting hand sanitizer spray that promises to kill germs for 24 hours after application. Its active ingredient, AmosilQ, creates a barrier layer of microscopic spikes all over your skin. These spikes kill germs by poking holes in them. It covalently bonds to your skin and stays on for up to 24 hours even with hand washing. It is non-toxic and none of it is absorbed into your body, according to the company. Is it the miracle that we all have been waiting for? I wanted to test Qore-24 for its "immediate kill" ability. After work, my husband put his "dirty" (but visibly clean) right hand fingertips onto an agar plate. Then I sprayed 20 sprays of Qore-24 on his left hand. I rubbed it in and let it dry for 2 minutes. Then he pressed his Qore-24 treated left fingers into the agar. As you can see, Qore-24 did an excellent job killing the bacteria!
Qore-24 Immediate Kill
How well does Qore-24 work if you only use 2 sprays?
In my experiments, I have been using tons of sanitizer to fully cover the hands. Most people aren't really using 20 sprays. They are putting 2-3 sprays on one palm and then rub their hands together. Then they assume that everything has been killed. I wanted to test this. After work, my husband pressed the dirty fingers on one hand onto an agar plate. Then I sprayed 2 sprays of Qore-24 onto his other hand. I rubbed it in up to his fingers as best I could wearing a gloved hand paying careful attention to his finger tips. (I didn't want him to rub his hand together because his other hand already had agar goo on it.) It dried quickly and he pressed his treated fingers/thumb onto an agar plate. As you can see, there is still a lot of growth on that plate. I think we all now know, that whatever type of hand sanitizer you use, it is important to use A LOT of it if you actually want to kill most of the germs.
How well does Qore-24 work on dirty / muddy hands?
As you can see in the results above, the alcohol hand sanitizer (Clorox Hand Sanitizer Spray) did not work well at all if the hands were soiled with dirt. I decided to test and see if Qore-24 worked better on dirty hands. My children, Jon and Katie Scarlett, got their hands dirty outside. Then they placed their dirty right hands on the agar plate. Then we sprayed 20 sprays of Qore-24 on the dirty left hand and I rubbed it in. I was impressed because the Qore-24 actually took the dirt OFF their hands and they looked clean afterwards. Then they pressed their Qore-24 treated left hands onto a plate. After 18 hours of incubation, this is what the plates looked like. I am very impressed! Qore-24 did an excellent job killing germs on dirty hands! This is a good hand sanitizer to take on a picnic!
Does Qore-24 continue to work all day?
Since Qore-24 is supposed to continue working all day, I wanted to test whether or not spraying Qore 24 on kids' hands before school actually translated to LESS LIVE bacteria on their hands at the end of the school day. I had my son Jon (2nd grade) a neighbor Abby (2nd grade), and a neighbor, Molly, (Kindergarten) try it out. Before school, I had the children put their right hands into their pocket (to make sure no spray accidentally got on the right hands). Then I sprayed tons of Qore-24 onto their LEFT hands. I used 20 sprays on each hand. Their hands were soaked and dripping. I wanted to make sure that there was no question about whether or not enough spray was used. I rubbed the spray into their hands myself. They held their hands in the air until they were completely dry. Then they went off to school. They were told to wash their hands as they normally would at school. Each child washed their hands once or twice during the day at school. After school (7 hours and 45 minutes after application), they came back to my house. I had them hold their hands up in the air for 1 minute to give any recently touched germs a chance to die. I looked at their hands and none of them were visibly dirty. Then they placed their right "dirty" fingers into an agar plate and their left "Qore-24" fingers into another plate. The plates were incubated for 20 hours at 95 degrees F to allow any LIVE bacteria or fungus to grow. If the product works like they claim, there should be much less bacteria on the plates where the hands were treated with Qore-24.
7.5 hours after Qore-24 application
As you can see, my results don't show any significant difference in the amount of LIVE bacteria on each hand. This was the second time that I had done this experiment. I had done it 1 week earlier with my son Jon. Here are my son Jon's results from that first test. This time I sprayed his right hand with Qore-24. Even with the bad lighting this photo was taken in, you can see that the amounts of bacteria on both hands are essentially the same.
I also tested Qore-24 on my husband. I sprayed at least 20 sprays on his left hand before work at 7:45am. His right hand hid in his pocket while I rubbed the Qore-24 into his left hand. He held it up in the air to dry and left for work. He had a long day that day and didn't get home to put his fingers on the agar plates until 7:30pm. So, it had been almost 12 hours. His big fingers barely fit into the plate so all he really managed to do was get his 4 fingertips and his thumb in there. He also pressed too hard and poked some holes. Regardless, there isn't a significant difference in the amount of bacteria on the Qore-24 treated left hand verses the untreated right hand.
Just in case the Qore-24 results worked better for a shorter time period, I tried a 3 hour experiment. I sprayed one of my son Jon's hands and one of my husband's hands with tons of Qore-24 at 5pm before they left for a Laser Tag birthday party. Neither of them washed their hands or used hand sanitizer at the party. They put their fingers on the agar plates when they got home at 8pm. As always, I had them hold their hands up in the air for 1 minute to give any recently touched germs time to be killed before they put their fingers on the agar plate. The left plate in each photo is the unsprayed hand and the right plate is the Qore 24 treated hand. Unfortunately, I still don't see any significant difference.
3 hours after Qore-24 application
My experimental results have shown that Qore-24 is an excellent hand sanitizer for "immediate kill" even on soiled hands, but I have not been able to show that it continues to work all day. I contacted Qore-24 and they sent me all of their research data. Their data looks fantastic, and it looks like the product is amazing. Their data shows that there should be 92% less bacteria on a Qore-24 treated hand than on a control hand after 24 hours. This is what Qore24 has to say about my experiments.
"As we applaud your at home experiments, it is not a scientific way to conduct this type of testing. We have undergone years of testing to get this product to market by independent 3rd party certified labs under strict protocol. We have done over 15years of testing in order to get our product approved to sell by the FDA. We stand by our product and all the claims we make and they are backed by testing to prove it. We will be posting those test on our website shortly so please look for them there as well as on FB. This product is on it's way to change healthcare standards throughout the industry and is truly a life changing product."
I wish the Qore24 people had a specific comment as to why my experiments wouldn't accurately demonstrate the effectiveness of Qore 24. I would like to know why my experiments WERE able to demonstrate how great Qore24 is at killing bacteria immediately upon application. They are also great showing how Qore 24 works on dirty hands. Why wouldn't they be able to show that it continues to work all day? I realize that my experiments are not accurate for counting exact numbers of bacteria. They are only good for looking at BIG differences. However, I thought "92% less bacteria" should result in a noticeable BIG difference on an agar plate. The bottom line is that there are still an awfully lot of live bacteria on those Qore 24 treated hands a few hours after application. Qore24 has also not been shown to kill norovirus so it is not on my list of favorites.
Zylast is a great new hand sanitizer that actually kills norovirus! It is also supposed to continue working for 6 hours after application. I decided to test the Zylast antiseptic. It is a clear gel with an active ingredient of ethanol.
First, Katie pressed her "dirty" right hand onto an agar plate and rubbed it around. Then, I applied a small amount of Zylast to her left hand (size of a dime). I rubbed it in and let it dry for 2 minutes. Then she rubbed her left hand onto another clean agar plate. I let the plates incubate overnight. As you can see, the Zylast did a fabulous job killing the germs!
I repeated this experiment but we started with extra dirty hands. Katie rubbed her hands in actual dirt. As you can see, the Zylast still did a great job even in the presence of real dirt!
Next I wanted to see if Zylast continued to work for 6 hours like they say. For this experiment, I had Jon and Katie wash and dry their hands. Then I put Zylast on one of their hands. Then I let them go and play for 2 hours. They were not allowed to go outside or wash their hands. Jon went to Karate class. After 2 hours, they held their hands up in the air for 3 minutes to allow time for any recently touched germs to die. Then they pressed each hand into an agar plate. The plates were incubated overnight. Unfortunately, there was no big difference in the amount of bacteria on their hands. I repeated this 2 hour experiment many more times and the results were always the same.
Next I tried to see if the Zylast was still working after 30 minutes. Jon washed and dried his hands. Then I put Zylast on his left hand. He let it dry and then went off to play inside. He was not allowed to touch any actual dirt, but I had him crawl on the floor and touch some lettuce leaves to get some germs. After 30 minutes, he held his hands up in the air for 3 minutes to give the Zylast time to work its magic on any recently touched germs. Then he pressed both hands onto an agar plate. The plates were incubated overnight. There was no difference in the amount of bacteria. Zylast antiseptic is still my favorite though because it kills the norovirus surrogate and works on dirty hands.
Zylast lotion has NOT been tested for its ability to kill norovirus. However, I decided to test its "immediate kill" ability anyway. For this experiment, I had Jon and Katie go outside to play for a few hours. When they came inside, Katie's hands were FILTHY with actual dirt. Jon's hands still looked clean (so I didn't take a picture of his).
I had them both rub their dirty right hand onto a clean agar plate. Then I wore clean gloves and rubbed a dime sized amount of Zylast LOTION onto their left hand. The Zylast lotion actually removed most of the dirt on Katie's hand and her hand looked MUCH cleaner. The kids held their Zylast hand up in the air for 1 minute to let it dry. Then they rubbed their Zylast hand onto another clean agar plate. The plates were incubated overnight.
As you can see, I have not been able to show that Zylast continues to kill germs after it is applied. I could not show that Qore24 continues to work, either. Perhaps they really do keep working but for some reason these experiments do not show it. I have no idea why that would be. All I know for sure is that just because you have applied Zylast or Qore 24, your hands are NOT germ-free. If you have the opportunity to wash your hands before eating or reapplying hand sanitizer at that time, I would do so. They are both great at killing germs immediately upon application, though. Zylast claims to kill norovirus and Qore 24 does not.
What works better Zylast Antiseptic or Purell Advanced?
My previous experiments have showed that hand sanitizers containing primarily alcohol don't work very well on dirty hands. The alcohol doesn't penetrate the dirt very well. Zylast (76% ethyl alcohol) has done a great job on dirty hands most likely because of that extra ingredient, benzethonium chloride. But how does it compare to Purell Advanced which contains 70% ethanol? I did this experiment on the countertop instead of on hands. I divided the countertop into 4 squares using masking tape.
Then I made "germ water" using dirt from outside and some bacteria from an agar plate that I rubbed my fingers and some spinach leaves on the day before. I put 1.25 milliliters of "germ water" on to each square and spread it around to completely cover the square. I let the squares dry for about 2 hours.
When the squares were dry, I put 1/4 teaspoon of Zylast on the Zylast square and 1/4 teaspoon of Purell Advanced on its square. I also put 1/4 teaspoon of water on the dirty control square. I spread the hand sanitizers and water around to completely cover the squares. I let them sit for 1 minute and then used sterile swabs to collect samples from each square. I rubbed the swabs onto agar plates and let them grow overnight in my warm incubator (about 98 degrees F).
After several requests, I tested the Ava Anderson Non-Toxic hand sanitizer. It smells like lemons and did not sting hands. To do these experiments, I used my children's hands when they got home from school. First they rubbed their dirty thumbs on one agar plate. Then I put .5mL of the Ava hand sanitizer on their left fingers. That amount was plenty to soak their fingers, and I rubbed it in thoroughly for about 20 seconds. Then I had them hold their hand up in the air for 1 minute while the hand sanitizer worked. After the minute was up, the kids rubbed their fingers all over an agar plate. Then I put .5mL of Zylast onto their right fingers and rubbed it in. After 1 minute, the children rubbed those fingers on an agar plate. The plates were incubated for 24 hours. I repeated this experiment several times on different days. I can't put all the results up because this page is already WAY too big. The amount of bacteria on the "dirty thumbs" controls varied greatly. I can't tell if this bacteria is the good bacteria naturally found in our skin or bad bacteria picked up at school. It is probably a mixture of both.
My little Michael also wanted to help do hand sanitizer experiments. He is too little to understand how to rub just his dirty thumbs on the plate. However, he could handle rubbing one hand on a plate. So, I tested each hand sanitizer on him on different days after he had been playing outside for hours.
As you can see from the results of my experiments, the Ava hand sanitizer doesn't seem to produce a significant decrease in the amount of bacteria. Maybe it kills some bacteria, but it is just not a HUGE difference like the Zylast. The Ava Non-toxic Hand Sanitizer does not claim to kill a certain percentage of germs so the results aren't that surprising. Some natural hand sanitizers claim to only kill bad bacteria and not good bacteria. I don't know how they accomplish that (and I find it hard to believe) but perhaps that is what is going on here. I do LOVE many of the other Ava Anderson products, though. I love my spf 15 face lotion and the deodorant is amazing! I will never use another deodorant because I love the Ava anderson deodorant so much!
Silver SoftTM Hand Sanitizer is an exciting product that uses chelated silver to kill germs. It promises to kill 99.9994% of germs including bacteria, viruses, and fungi. It is available here on Amazon. I am intrigued by the potential of silver and was very excited to test this product. It is a foam hand sanitizer that does not hurt at all so my kids loved testing it. After school, I tested the hand sanitizer on my children and a few neighbor friends. First the children rubbed their dirty thumbs on an agar plate. Then I put 3 pumps of of Silver Soft Hand Sanitizer on their left fingers. That was plenty to soak the fingers. I rubbed the hand sanitizer all over the fingers with my clean gloved hands for about 15 seconds. Then I set a time and let the sanitizer dry for 1 minute to give it time to work. Then the children rubbed their silver soft fingers all over the appropriate agar plate. I repeated the procedure with Zylast and their right fingers. I put a dime sized amount of Zylast on their left fingers and rubbed it all over the fingers with my clean gloved hands. After 1 minute, the children rubbed those fingers all over another agar plate. The plates were incubated for 24 hours. My little Michael wanted to do the experiment, too. He was not coordinated enough to just rub his thumbs on a plate. So, I just tested the silver soft on his whole hands. That is why Michael is the only one that has only 2 agar plates.
colloidal silver on this page.
GFS BioProtect is one of the few hand sanitizers that has actually been tested and shown to kill a norovirus surrogate. It killed 99% of murine norovirus. It is also the ONLY hand sanitizer that I'm aware of that works against a norovirus surrogate AND does not contain alcohol, and therefore, doesn't sting hands. You all know that I love my Zylast antiseptic but in the winter my hands are cracked and bleeding. I often simply don't use my hand sanitizer at all because it hurts too bad. I was excited about testing this non-stinging option. The BioProtect also smells really good.
In this experiment, I compared BioProtect to Zylast, 3% hydrogen peroxide, and Purell Advanced on my countertop. I did the experiment like I always do.
I made germ water with dirt from the back yard and extra bacteria from a previous days agar plate.
I put 1mL of germ water onto each square.
I rubbed the germ water around with my gloved hand and let it completely dry which took about 2 hours.
I used a sterile swab to rub on the dirty control square.
I rubbed each swab onto its respective agar plate.
Then I added .5 mL of each product (Zylast, hydrogen peroxide, and Purell Advanced) to its respective square and rubbed it in with my clean gloved hand. I let it sit for 1 minute and then swabbed each square and rubbed the swabs onto agar plates. Since the BioProtect is a foam, I could not accurately measure it. Instead, I used 4 pumps of the BioProtect and rubbed that around the square.
The plates were incubated overnight it my warm incubator.
As you can see, the BioProtect did a great job killing bacteria on the countertop just like Zylast and 3% hydrogen peroxide. As usual, Purell Advanced does not do a very good job.
How well does BioProtect work on actual kid's hands?
For these experiments, I had my kids and some neighbor kids go out and play and get their hands dirty. All hands had a lot of actual dirt on them.
Then they rubbed one dirty hand onto an agar plate.
I put 4 pumps of BioProtect on the other hand, rubbed it in, and let it dry for 1 minute. Then the child rubbed their sanitized hand onto another agar plate.
The plates were incubated overnight in my warm incubator. As you can see, the BioProtect did a great job killing bacteria even on these filthy hands.
BioProtect Extended Kill
GFS BioProtect hand did have less bacteria on it than the control hand. However, in a few of the experiments, the hands looked about the same. I have never been able to show that Zylast or Qore24 continues to work, either. In fact, the BioProtect at least had a few experiments where it looked like it continued to do a little something. I am not saying that the hand sanitizers don't work like they claim. All I know for sure is that your hands aren't as germ-free an hour later as they were right after you put on the hand sanitizer and that goes for all of the extended kill hand sanitizers that I have tested. I still love GFS BioProtect , though, because it is the only hand sanitizer that kills a norovirus surrogate and does not sting hands. I would just reapply or wash hands before eating if you can.
Clean Smart Hand Cleanser is a DIFFERENT hand sanitizer compared to the others that I have tested. It does not contain alcohol and boasts to contain no harmful chemicals. Its active ingredient is hypochlorous acid. I tested the Clean Smart Hand Cleanser on my kids dirty hands. These hands had actual dirt on them because the kids were playing outside. The kids rubbed one dirty hand onto an agar plate. Then I sprayed 10 sprays of the Clean Smart and rubbed it all over their other hand. I let it dry for 1 minute. Then they rubbed their hand onto another agar plate. The plates were incubated for 24 hours in my warm incubator.
As you can see, the Clean Smart does not appear to be strong enough to handle dirty hands. To be fair, most of the alcohol hand sanitizers like the Clorox hand sanitizer do not work well on dirty hands either. So, I repeated the experiment on very clean hands. For this experiment, the kids had been playing inside and their hands looked perfectly clean. I had them rub their right hands onto the plate. Then I put 10 sprays of Clean Smart on their left hands and rubbed it in. I let it dry for 1 minute and then they rubbed that hand onto another agar plate. The plates were incubated for 24 hours.
Well, I just can't recommend Clean Smart Hand Cleanser. It doesn't seem to be doing much bacteria killing in my experiments.
When neighbor kids come over to my house, they are often asked to try out a hand sanitizer. Caitlyn came in with visibly clean hands. I had her rub her dirty right hand onto an agar plate. Then I put 10 sprays of Clean Clappers on her left hand and rubbed it in. I let it dry for 1 minute and then she rubbed her other hand on another agar plate. As you can see, the Clean Clappers did not appear to do anything significant.
My 3 kids had pretty dirty hands from playing outside. I put 10 sprays of Clean Clappers onto their hands, rubbed them in, let them dry for 1 minute, and rubbed their hands onto agar plates.
essential oils page. I guess they just don't do much when diluted.
Comparing Young Living Thieves Waterless Hand Purifier to Zylast antiseptic hand sanitizer
Let me first say that a good thorough hand washing with soap and water is ideal. However, there are times when me must eat but can't get to a sink to wash hands. For example, my children are not permitted to wash hands before lunch at school. Some teachers claim that hand washing takes too much time. I think that is ridiculous, of course. However, there are times when you need a good hand sanitizer and I've been trying to find the best ones. I have already tested many hand sanitizers on this page.
For this experiment, I wanted to determine if the Thieves Waterless Hand Purifier really killed bacteria. I got the Thieves Waterless Hand Sanitizer here. For this experiment, I used my children's hands and some of their friend's hands. First they rubbed their thumbs all over the dirty control plate. Using a disposable 1mL syringe, I put .5mL of Thieves Waterless Hand Purifier onto their left fingers and rubbed it in with my clean gloved hand. I let the fingers dry for 1 minute, and then they rubbed their fingers all over the agar plate. Finally, I put .5mL of Zylast antiseptic hand sanitizer onto their right fingers. I rubbed it in with my clean gloved hand. I let it dry for 1 minute and then they rubbed those fingers all around an agar plate. I put the plates in my warm incubator for 24 hours to let the bacteria grow.
Zylast antiseptic is a wonderful product! It kills norovirus and works on dirty hands! Sometimes people complain that it leaves a sticky film. You can order it from http://www.zylastdirect.com/catalog.php. If you use the coupon code "StopNorovirus" you will get 10% off your order. I recommend getting Zylast Antiseptic and NOT Zylast Lotion. The lotion has never been tested for its ability to kill norovirus. Zylast antiseptic is also available on amazon.
As you can see, the Thieves Waterless Hand Purifier did a very good job! It is important to note that these hands did not have ACTUAL DIRT on them. As you will see when you keep reading, most hand sanitizers ( except Zylast) don't work well on hands with actual dirt. So, if you or your child's hands are actually dirty, you need to wipe them off with a wipe before using the Thieves Hand Purifier.
Comparing Homemade Thieves/Witch Hazel Spray with Clorox Hand Sanitizer Spray
For this experiment, I made my own Thieves hand sanitizer. I used 15 drops of Young Living Thieves oil, 1 teaspoon Witch Hazel, and 5 teaspoons of distilled water. I put it in this amber glass spray bottle. Since it is a spray, I compared it to the Clorox Hand Sanitizer Spray that I purchased from Amazon. (The Clorox Hand Sanitizer Spray is primarily ethanol and does not contain chlorine bleach.) For this experiment, I had the kids rub their thumbs all over the dirty control plate. Next, I sprayed 8 sprays of the homemade thieves spray all on their left fingers, and I rubbed it in with my clean gloved hand. I let it sit for 1 minute, and then the kids rubbed those fingers all over the agar plate. Finally, I sprayed 5 sprays of the Clorox hand sanitizer all over the right fingers. I only used 5 sprays because that seemed to make the fingers wet enough. I rubbed it in with my clean gloved hands and let it sit for 1 minute. Then I had the kids rub their right fingers all over another plate. I incubated the plates for 24 hours in my warm incubator to let bacteria grow.
As you can see, the homemade thieves spray killed some germs but I don't think it does enough to be actually used as a hand sanitizer. I wouldn't trust it. It is also important to note, that these hands all looked clean. They did not have actual dirt on them. As you will see when you keep reading, most hand sanitizers (except Zylast) don't work well on hands covered in actual dirt.
How does the Thieves Waterless Hand Purifier and the Homemade Thieves spray do in the presence of dirt?
I have done many hand sanitizer experiments in the past (which you can see here) that show that most alcohol based hand sanitizers don't do well on hands with actual dirt on them. The alcohol just can't seem to penetrate the dirt. I wanted to know how the Thieves Waterless Hand Purifier and the homemade Thieves Spray do when actual dirt is present. Normally, I would send my children outside to play and then they would come in with dirty hands. However, since there is 6 inches of snow on the ground and the temperature is below zero, this is not an option. So, I tested the hand sanitizers on the dirty countertop, just like I did for the first experiments on this page. I put 1.25 mL of dirty "germ water" on each square, rubbed it all around and let it dry. Then using disposable 1mL syringes, I added .5mL of each hand sanitizer to the appropriate square. I rubbed them all around with a clean gloved hand. I timed them each for 1 minute and then took swabs of the squares. I rubbed the swabs all around the appropriately labeled agar plate. The plates incubated for 24 hours.
To sum up, I am surprised and impressed with how well the Thieves Waterless Hand Purifier killed bacteria in my experiments. Its main ingredient is ethanol like most other hand sanitizers so it is not really THAT surprising that it kills bacteria. We don't know if it would kill norovirus, though. It is also important to wipe off your hands with a wet wipe before using the hand purifier if you have visible dirt on your hands. The Thieves Hand Purifier also smells WONDERFUL. It smells like peppermint and smells so delicious that you need to be careful that your kids don't eat it. If you would like to buy Thieves Hand Purifier, you can order it from www.striveforhealthy.com or buy it from another authorized Young Living seller. Do not buy it from Amazon. Many Young Living Products on Amazon are counterfeit.
As I expected, only the Zylast Antispetic hand sanitizer was able to cut through the dirt. Don't feel too bad, Thieves lovers. Purell Advanced and the Clorox Hand Sanitizer do not do well in this test either. My advice is that if you use any hand sanitizer besides Zylast antiseptic, wipe dirt off your hands with a wipe before using your hand sanitizer.
Clorox Hand Sanitizer Spray has always been a favorite of mine because it is one of the few tested to kill norovirus. It is primarily ethanol and does not contain any chlorine bleach. It dries nicely leaving your hands feeling clean. It is important to wipe off your hands with a wipe before using this hand sanitizer if they are visibly dirty. Clorox Hand Sanitizer is available from a reputable seller on amazon. Of course, I LOVE the "Norophobe Zone" magnet that this pack of hand sanitizer comes with.
If someone in your house actually has vomiting or diarrhea, I would suggest washing your hands well with soap and water and wearing disposable gloves as much as possible when taking care of the sick person. You can also use Zylast , Clorox Hand Sanitizer, BioProtect, or Germstar Noro which have all been tested and shown to kill norovirus. I don't see any reason to use a hand sanitizer at all if you aren't going to kill the really bad stomach bugs. Of those four, Zylast antiseptic and BioProtect are my favorites because they work on dirty hands.I f no one in your house has a stomach virus, or a serious illness, I would just recommend normal hand washing at home. Our skin is embedded with good bacteria that we NEED so we certainly don't want to kill all of it. We just want to kill germs on the surface and only on certain occasions. I do not use hand sanitizer around the house. I just wash my hands. If I'm giving my kids a snack at a petting zoo, I want a hand sanitizer that kicks butt. You can order Clorox Hand Sanitizer and Germstar Noro on amazon. You can also order Zylast antiseptic on amazon or from http://www.zylastdirect.com/catalog.php and use coupon code "StopNorovirus" to receive 10% off your order (That code only works on the Zylast direct website, not on amazon).
Would you like to suggest an experiment or donate?
I have many more experiments to do! I'll be posting all of my dishwasher results soon. I have tested the PureWash Pro laundry system and will be posting those soon. I am also working on experiments testing many more cleaning products including Honest Company and Better Life. If you would like to suggest a product or experiment, please e-mail me firstname.lastname@example.org. If you would like to be informed when new results are posted, please like my facebook page. I always post on there when new results are up. If you would like to help support my work, please use my Amazon links when you shop on amazon. I have an Amazon affiliate account. If you use any of my Amazon links when you shop on Amazon, I get a small percentage of the sale. For example, you can click to Amazon using the link for my daughter's book and buy something. It doesn't matter what you buy, but I will get a small percentage of the sale. I use that Amazon money to buy agar plates and all the supplies that I need to do these experiments. If you don't want to bother using amazon links, you are welcome to send me a small donation through paypal. If you really want to brighten my day, please buy one of my daughter's books. They are excellent! If you don't have a little girl to give them to, buy a copy for your local elementary school library or children's hospital.
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If you want to read more of my experiments, please check out this list.
Lastly, before you leave, please brush up on your knowledge of stomach bugs so you can help decrease their spread by reading this page of my website. Thank you!
--Annie Pryor, Ph.D
phd.annie at gmail.com
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