MOXĒ scientists explain why disinfectants with higher alcohol concentration don’t always work best and why you should use a 70% alcohol disinfectant.
These days, knowing all you should about the disinfectants and sanitizers you use is a must. Especially when something like 70% vs. 95% alcohol content could mean the difference between contracting Covid-19 and staying virus-free.
Alcohol, especially Isopropyl alcohol, is a common surface sanitizing ingredient but it has varying levels of efficacy depending on its purity in a solution. Though it may seem a little counter-intuitive, 70% isopropyl alcohol has proven to be a more effective sanitizing agent than its higher purity counterparts (e.g. 90-99%).
In this post, we'll discuss all the reasons less is more when it comes to alcohol concentration in disinfectants.
Before we discuss further…
At MOXĒ, our heart and thoughts are with those who have suffered a loss to the coronavirus pandemic. Special appreciation to frontline health workers, government at all tiers, and all who have made – and are still making – efforts to curb the spread of the deadly virus.
That said, as information about the coronavirus continues to spread, some questions have been left unanswered.
Why is 70 percent alcohol a better disinfectant than 95 percent alcohol?
Many think high-percentage alcohol solutions offer greater protection against germs. The theory behind this is that since alcohol is the main active ingredient in the CDC recommended alcohol-based sanitizers, more alcohol should automatically mean greater efficacy.
But, this isn’t entirely correct and we’ll explain why.
Before we review the effect of alcohol concentration in hand rubs, let's quickly discuss the relationship between alcohol and germs.
Does Alcohol Kill Germs?
Sure it does – through a process called denaturation.
Denaturation refers to the effect alcohol molecules have on fat membranes enveloping bacteria or virus cells. The alcohol breaks down the fat membrane, exposing the internal part of the cell and all its essential components. When exposed, the cells dissolve and soon die.
However, for effectiveness, the CDC (Centers for Disease Control and Prevention) categorically recommends alcohol-based hand sanitizers with between 60 and 90 percent alcohol as most effective for sterilization purposes.
Alcohol-based Sanitizers
Isopropyl alcohol, also known as rubbing alcohol or IPA, is synthesized instead of distilled from grains or other plants. It is highly toxic when ingested and is not a type of alcohol you can drink, however, it's the most commonly used alcohol for sanitizing, particularly in medical and pharmaceutical industries.
IPA, and most alcohols in general, are very volatile compounds. This means they evaporate very quickly at normal temperatures.
This brings us to one of the main drawbacks of purer alcohols in sanitization...
Why Choose 70% Alcohol-Based Hand Sanitizers Over 95% Hand Sanitizers?
Health experts recommend between 60 and 90 percent alcohol-based formula as most effective. Any formulation above this percentage may be much less effective for a couple of reasons.
If you look at the directions on the back of any type of sanitizer or disinfectant bottle or container, you'll likely find instructions for how long you should keep the surface or substance visibly wet with product for effective disinfection. This time period is called a contact time.
Pure alcohols, volatile as they are, make it difficult to achieve this contact time on a surface because they dry out in seconds whereas the average contact time for most disinfecting agents is at least a minute. This means bacteria or germs aren't making contact with the disinfectant long enough for them to be killed.
For this reason, to achieve the appropriate contact time, IPA is diluted with water to around 60-70% so that it evaporates much slower.
For instance, 70 percent of alcohol solutions contain about 30 percent purified water. This water content plays a crucial role in inhibiting pathogenic microorganism growth.
Water serves as a catalyst and facilitates the denaturation of cell membrane proteins. Sanitizers with 70 percent alcohol solution penetrate the membranes more effectively, coagulating the proteins and killing microorganisms.
Therefore, adequate water content is essential to alcohol-based disinfectants to ensure efficacy.
As mentioned, in most cases – like preventing coronavirus spread – concentrations above 90 percent might be considered too concentrated.
Do 70 Percent Alcohol-Based Sanitizers Kill All Viruses?
No.
It largely depends on the particular virus in question. Like coronavirus and rhinovirus (the common cold virus), some viruses come with an “envelope” that may only be broken by a formula with no less than 60 percent alcohol.
Even still, some viral structures cannot be destroyed by alcohol, regardless of the concentration.
Here’s where handwashing, again, reigns supreme. Soap and water flush off all forms of bacteria and viruses in addition to dirt and grime.
How to Use Alcohol Effectively for Sanitizing
A quick reminder – insist on hand sanitizers with at least 60 percent alcohol concentration.
Keep all alcohol-infused products away from pets and children. Remember, too, that alcohol-based products are highly flammable and should be kept far from flames.
Hand sanitizers are usually well-sealed to prevent alcohol evaporation that could make the product less effective over time.
FAQs
Can I make my own DIY 70 percent alcohol-based hand sanitizer?
While the FDA has issued some guidelines for temporary preparation for the public health emergency caused by coronavirus, the agency strictly dissuades DIY homemade options.
Poorly made hand sanitizers do not only expose you to contamination risk, many users report skin burns and other irritations from their homemade solutions.
Where Can I buy 70 percent alcohol-based hand sanitizers?
Hand sanitizers are widely available in pharmacies and retail stores. However, in the wake of the coronavirus, hand sanitizers have been flying off shelves of retail outlets and pharmacies. This, understandably, has caused scarcity.
Not sure where to get your FDA-regulated hand sanitizers? MOXĒ offers CDC-recommended high-quality alcohol-based sanitizers.
You can place your order from our online store right away. Alternatively, MOXĒ sanitizers are available at Costco stores nationwide.
Many disinfectants and surface cleaners promise to fight against SARS-CoV-2. Can I apply them on my hands as a preventative measure against coronavirus?
No, you shouldn't.
Avoid using disinfectant wipes or sprays on your skin. These products are specifically formulated as surface cleaners. These agents could cause eye and skin irritation – whether for humans or pets.
Too often, the contents of these products are not skin-friendly. They are intended for tough surfaces.
Can I add some alcohol to non-alcoholic sanitizers to increase their effectiveness?
No.
Your hand sanitizer is either alcohol-based or non-alcohol based. Mixing up these two options will mostly offer an ineffective product.
While alcohol-free sanitizers may serve in a pinch, always prioritize alcohol-based solutions, as recommended by the FDA.
My hand sanitizer contains methanol – wood alcohol. What are the risks?
FDA has warned health care professionals and consumers against methanol (also called wood alcohol) contaminated hand sanitizers. This particular alcohol is toxic and dangerous.
Methanol is said to trigger severe adverse reactions when it penetrates the skin. Blindness or even death is likely if ingested.
Most sanitizers contaminated with methanol do not list methanol on their ingredient list – since it's unhealthy. To be double sure, you may have to check the FDA list of hand sanitizers customers should not use.
Are natural hand sanitizers effective?
So far, there are yet no recognized effective herbal or natural hand sanitizers for germs. Until more research reveals otherwise, the recommended hand sanitizer is one with between 70 to 90 percent alcohol concentration.
Conclusion
Are 70 percent alcohol-based hand sanitizers more effective than 95 percent hand sanitizers?Yes.
While the CDC recommends hand rubs with 60-and-above-percent alcohol content, concentrations above 90 percent might be ineffective. Experts explain that such options contain less water, which is an essential ingredient in hand sanitizers.
Too concentrated a formula may evaporate too quickly before it properly penetrates the cell walls, leaving it unable to kill bacteria. This makes alcohol-based sanitizers with over 90 percent less effective and, therefore, not recommended for sanitizing.
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About MOXĒ
MOXĒ is a manufacturer of innovative health and wellness products focused on complementing any lifestyle. With our holistic approach, we add custom essential oil blends in everything we create and ensure every product is made with the highest quality ingredients to support clean living and peace of mind.
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