The science behind soap is what first got me hooked in this business. Plain old soap is a very powerful thing yet it is so simple and natural, which makes it super interesting to study! There have always been a ton of studies available that back up the effectiveness of soap, but during a pandemic fear can set in, everyone is talking about how to stay safe and things can get quite confusing. So let’s get nerdy and talk about the science behind soap!
**Warning, this is a long one full of linked rabbit holes you can go down for more information!!**
Three quick headlines from the following post for you impatient ones (like me):
- Basic soaps are superior for germ protection vs antibacterial or even hand sanitizers
- A communal bar of soap is safe and will not spread germs
- When no soap and water is available use a hand sanitizer with at least 60% alcohol
Where to start?
Well let’s start with one of my favorite soapy studies which was updated recently (2006) and used a flu strain that you likely have heard alot about recently - H1N1. The test had volunteers (vaccinated and antibody positive health care workers) willingly contaminate their hands with the live H1N1 virus then they followed one of a variety of hand washing methods. They either washed with soap and water, or used one of three varieties of rub on/leave on hand sanitizers. Their hands were then retested for the presence of the virus. Results were that either method was ‘highly effective in reducing the virus on human hands, although soap and water is the most effective intervention.’ This also means that if someone who is sick uses a bar of soap before you, contaminating the bar with germs, the germs do not transfer to you! You might be grossed out by the idea of someone else using the bar before you, but it is safe - soap sanitizes itself! There are plenty of previous studies directly on communal soap use if you are interested in more dirty clean details!
Great, so the study says soap is awesome, but WHY?
Well it starts with the way soap ‘cleans’ but before we get to that we have to cover one more thing! What I like to call “clean” terms - these have been thrown around A LOT lately and we are overdue for some definitions so we can use the terms correctly. Once we have these down we will dig into the details a bit more on the two that are focused around soaps - Cleaning and Sanitizing.
Cleaning vs Sanitizing vs Disinfecting vs Sterilizing
The definitions below are from the CDC and are a bit hard to visualize, plus we think our cheat sheet is just easier to follow!
- Cleaning: removes germs, visible dirt, and impurities from surfaces or objects. Cleaning works by using soap (or detergent) and water to physically remove germs from surfaces. This process does not necessarily kill germs, but by removing them, it lowers their numbers and the risk of spreading infection.
- Sanitizing: lowers the number of germs on surfaces or objects to a safe level, as judged by public health standards or requirements. This process works by either cleaning or disinfecting surfaces or objects to lower the risk of spreading infection.
- Disinfecting: kills germs on surfaces or objects. Disinfecting works by using chemicals to kill germs on surfaces or objects. This process does not necessarily clean dirty surfaces or remove germs, but by killing germs on a surface after cleaning, it can further lower the risk of spreading infection.
- Sterilizing: describes a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods.
Ok so soap is in the “Cleaning” category, got it. But exactly HOW does soap clean?
A soap molecule has 2 sides, one that is hydrophilic ('water-loving') and hydrophobic ('water-hating').
When grease or oil is mixed with a soap-water solution, the soap molecules work as a barrier between the water and the grease/oil, keeping the two separate. You mix the soap-water solution with the grease/oil by lathering the soap in your hands and the soap suspends the oil/dirt in such a way that it can be removed or washed away.
English translation: When you are washing hands with soap and water, the agitation of lathering the soap loosens the grease/oil/germs from the surface of your hands and encases them in soap. They suggest to lather for 20 seconds to ensure you’ve got everything out from under your nails and between your fingers. When you rinse the soap from your hands you are also rinsing the grease/oil/germs down the drain.
Again, pictures are easier to follow!
Great, so why would I use regular soap when there is antibacterial soap? What about Hand Sanitizers?
Headline: ‘The FDA supports the CDC’s reco to use plain soap and water to wash. If water is not available use hand sanitizer’
Antibacterial products are in the “Sanitizing” category, which means they reduce the number of microbes on a surface to a safe level, they do this through the use of chemicals or alcohol. Consumer antibacterial products are regulated by the FDA as over-the-counter drugs* and described using two categories: Washes and Rubs. Again, let’s start with definitions:
- Washes - Antibacterial soaps, used with water and rinsed after use. Hand wash, hand soaps or body wash. Use of chemicals.
- Rubs - Leave on products of hand sanitizers or wipes. Used when soap and water are not available. Not rinsed. Hand sanitizer sprays and gels use between 60-95% alcohol base.
*Wait, hold on! Why are antibacterial soaps considered an ‘over-the-counter drug’??
In short, because of the claims made on the packaging it is considered a consumer-based medicine. A benefit of this categorization is that these products are required to go through additional review and strict testing before being sold to consumers. The FDA also has the ability to recall any product with harmful ingredients. Another surprising ‘over-the-counter drug’ is sunscreen!
So why not use antibacterial soap?
The benefits of antibacterial chemicals do not outweigh the risks caused by the chemicals to both our bodies and the environment. There is also risk that these can result in antibiotic resistant bacteria. Let’s break this down.
- Recent studies found that many chemicals we had used for years to make products antibacterial are not safe for humans or the environment.
- The first chemicals used to create antibacterial soap were discovered in the 1940’s. But the chemical (hexachlorophene) was so dangerous, it was discontinued in the 1970’s. Dial corporation continued the research and a new form of antibacterial soap was patented in 1984 using a chemical called triclosan. The popularity of this ingredient quickly grew and until recently was found in many consumer-based products like soaps and shampoos, clothing and home goods as well as plastics.
A recent study by the FDA of triclosan and 18 other active ingredients associated with consumer antibacterial products, found that they are endocrine inhibitors, which are detrimental to both humans and the environment. Thus they are not what is called GRAS (Generally Recognized As Safe). These findings resulted in a 2017 federal ban of their use in many consumer-based products. A ban of this type occurs when the ‘active ingredient in a drug product does not provide clinical benefit but potentially increases the risk associated with the drug (e.g., from reproductive toxicity or carcinogenicity).
- Antibacterial ingredients have been found in community waste waters concerning environmentalists.
- Our home state of Minnesota was actually the first state in the nation to ban the ingredient triclosan in consumer hand and body washes!
- Use of the chemicals that create antibacterial products can result in antibiotic-resistant bacteria
- According to the FDA, studies have raised the possibility that triclosan and likely other antibacterial chemicals contribute to making bacteria more resistant. Some data shows this resistance may have a significant impact on the effectiveness of medical treatments, such as antibiotics.
- There is also additional research being done by the EPA, reviewing triclosan for use in pesticides. Their guidelines are to reevaluate each active ingredient every 15 years, so the process for change is much slower.
Ok, so is hand sanitizer ok?
Yes, alcohol based sanitizers are effective and safe to use, but should only be used when soap and water are not available, like while out and about. Here are some additional things to keep in mind:
- Are your hands clean? Sanitizers are not necessarily cleansing. Grease and grime reduce the effectiveness of sanitizers, so start with clean hands
- 60-95% alcohol base is recommended. Germs are not effectively killed below 60% and strangely enough alcohol content over 95% results in germs being stunned but alive - so stay in the sweet spot between 60-95% to be safe.
- Although a great way to sanitize, 60%+ alcohol is very drying on your skin. Be sure to use a product with added moisturizers to help protect your hands and reduce risk of cracks or irritation due to dryness. We have a great one for you here!
Ok! Yikes, that was a lot to digest, but I warned you! Hopefully you have a better understanding of how soap works, the reasons you should avoid antibacterial soaps and what to do when you don’t have access to soap and water! Do you have any other questions or anything you want further clarification on? Let me know in the comments below!
Now go wash your hands! Preferably with a bar of Sebesta Apothecary soaps and some water!
-Kim
