As part of the barrier actions intended to fight against the spread of Covid-19, the use of hydroalcoholic gels is part of the solutions for the rapid and effective inactivation of a wide range of microorganisms that may be present on the hands . Besides the WHO formula, there are homemade recipes.

When hand washing with soap and water is not possible, WHO recommends the use of a quick-drying hydroalcoholic (SHA) solution (or gel) designed specifically for hand disinfection.

These products contain alcohol (minimum concentration of 60%) or ethanol, an emollient, and sometimes an antiseptic. They are applied by friction without rinsing on dry hands and appearing clean (that is to say without visible soil).

Alcohol is active on bacteria (including mycobacteria if contact is prolonged) on enveloped viruses (SARS CoV 2, herpes, HIV, rabies, etc.), on fungi. However, ethanol is more active on viruses than povidone, chlorhexidine, or detergents used for simple hand washing. The antifungal activity of ethanol is important. The activity of alcohol depends on the concentration, its effectiveness quickly decreases on wet hands.

Its simple use makes it a gel that can be used anywhere and that is brought to stay in good sanitary habits.

The preparation and formulation of these products can now be carried out by establishments such as pharmaceutical laboratories for medicinal products for human use or cosmetology laboratories. 

According to the World Health Organization, the hydroalcoholic gel is composed of:

• 96% alcohol: more particularly ethanol which acts as an active substance to eradicate bacteria.
• 3% hydrogen peroxide to act as a spore inactivator and thus avoid skin irritation.
• 1% glycerin: glycerol more precisely which will act as a humectant.

This formula is recommended by the WHO for the preparation of hydroalcoholic solutions in pharmacies. Not for the general public.

The decree of March 23, 2020 adds 3 formulations validated for the manufacture of SHA in pharmacies:

• Formulation with ethanol: 96% V / V ethanol can be replaced with 95% V / V ethanol (842,1 mL) or 90% V / V ethanol (888,8 mL );
• Formulation with 99,8% V / V isopropanol (751,5 mL)

Applying the hydroalcoholic gel is similar to a classic hand wash with soap and water. It is recommended to rub your hands vigorously for at least 30 seconds: palm to palm, palm to back, between the fingers and fingernails to the wrists. We stop once the hands are dry again: this means that the hydroalcoholic gel has sufficiently impregnated the skin.

It can be kept for 1 month after first use.

Faced with the shortage and rising prices of hydroalcoholic solutions at the start of the pandemic, the World Health Organization (WHO) published a recipe for hydroalcoholic gel in its “guide to local production of hydroalcoholic solutions”.

For 1 liter of gel, mix 833,3 ml of 96% ethanol (replaceable by 751,5 ml of 99,8% isopropanol), 41,7 ml of hydrogen peroxide, commonly called hydrogen peroxide, available in pharmacies , and 14,5 ml of 98% glycerol, or glycerin, also on sale at the pharmacy. Finally, add cooled boiled water to the mixture up to the graduated mark indicating 1 liter. Mix everything well then pour the solution quickly, to avoid any evaporation, into the dispensing bottles (100 ml or 500 ml).

It is necessary to place the filled vials in quarantine for at least 72 hours in order to eliminate the bacterial spores potentially present in the alcohol or in the vials. The solution can be kept for a maximum of 3 months.

Other homemade recipes are available. For example, it is possible to combine mineral water (14 ml), hyaluronic acid (i.e. 2 DASH spoons) which allows the formula to gel while hydrating the hands, a neutral base of organic perfume composed of 95% organic vegetable alcohol (43 ml) and organic tea tree essential oil with purifying properties (20 drops).

“This recipe contains 60% alcohol in accordance with the recommendations of ANSES – and the ANSM (National Agency for the Safety of Medicines and Health Products), specifies Pascale Ruberti, Aroma-Zone R&D manager. However, as this is a homemade recipe, it has not been tested to meet the Biocide regulations, in particular the NF 14476 standard on viruses ”.

For daily hand washing, there’s nothing like soap. “In solid or liquid form, they are available in a neutral or scented version, such as Aleppo soap known for its purifying properties thanks to the bay laurel oil it contains, the emblematic Marseille soap and its 72 % minimum of olive oil, as well as cold saponified soaps, naturally rich in glycerin and non-saponified vegetable oil (surgras) ”, explains Pascale Ruberti.

“In addition, for a nomadic alternative and easier to achieve than a gel, opt for a hydroalcoholic lotion in the form of a spray: you just need to mix 90% ethanol at 96 ° with 5% water and 5% glycerin. You can also add a few drops of a purifying essential oil such as tea tree or ravintsara »