1-propanol - a friend or foe in hand sanitizer?

he heightened awareness of good hygiene in the midst of COVID-19 has led to the introduction of a plethora of hand hygiene products into the market. Among the different infection control products, hand sanitizer has become one of the essential products to minimise the spread of coronavirus through touch. Due to the shortage of hand hygiene products, many ad-hoc producers, such as distilleries, industrial chemicals suppliers and cosmetic manufacturers have started producing and distributing hand sanitizers to fill the vacuum. As much as this is welcomed, it also presents a conflicting situation and raises the question which many health authorities, such as the US Food and Drug Administration (FDA) are starting to address - rogue hand sanitizer!

Rogue hand sanitizer as the name suggests is a substandard product which contains sub-optimal concentration of alcohol, the wrong type of alcohol and microbial contaminants that can have detrimental/adverse effects when applied onto the hands. To inactivate enveloped viruses, such as SARS-CoV-2 (the coronavirus responsible for COVID-19), the hand sanitizer has to contain the right concentration of alcohol and be applied in the right way, and for the right duration (30 seconds) to render it effective (refer to reference 1,2). This, however, can seriously be compromised when a substandard hand sanitizer (e.g. containing the wrong concentration and type of alcohol) is used.

Since June 2020, the spotlight on rogue hand sanitizers has been brought to full attention by FDA through a series of warnings on methanol and subsequently, 1-propanol contamination in hand sanitizers (refer to reference 3).

Methanol, also known as wood alcohol is a substance often used to create fuel, antifreeze and as an industrial solvent. Methanol must never be used in products for human use because oral, pulmonary and/or skin exposures can result in severe systemic toxicity. When repeatedly used as a handrub, skin absorption resulting in chronic toxicity occurs, particularly if methanol-induced desquamation and dermatitis are present (refer to reference 4). Acute poisoning using undeclared methanol in hand sanitizer is not uncommon except that the frequency of adversity has been magnified in this unprecedented period of hand sanitizer used worldwide (refer to reference 4). Nonetheless, methanol is definitely not acceptable in hand hygiene products.

The reiteration of the non-acceptance of 1-propanol (also known as n-propanol, propan-1-ol) in hand hygiene products did not come as a surprise as the alcohol is not approved as an active agent by FDA (refer to reference 2). Other than America, 1-propanol is generally accepted as an active ingredient in the formulation of hand sanitizers (refer to reference 5,6,7) in other parts of the world. Although the prohibition of 1-propanol in hand sanitizer is currently restricted to the USA, the question that comes immediately to mind for both healthcare professionals and the public is whether the warning from FDA on 1-propanol is of concern?

Let's approach this question from 2 aspects, firstly looking a little bit deeper into the FDA announcement (e.g. rationale, warnings etc.) followed by what the current scientific findings has to say.

The FDA warning is valid in terms of targeting rogue hand sanitizer manufacturers who misrepresented their formulation, fraudulently labeling the product to contain either ethanol or isopropanol but mixed with 1-propanol instead. This misrepresentation is unethical as well as dangerous in the event of adverse effects (e.g. ingestion) as accurate information of the ingredients within the product is critical in the providence of appropriate intervention. Importantly, the warning for 1-propanol is targeted towards misuse (e.g. treating hand sanitizers as drinkable alcohol substitutes) rather than as a result of its intended use for application onto the hands. As to most alcohol-based infection control products (be it ethanol, isopropanol or 1-propanol in this case), hand sanitizer is primarily indicated for use as a disinfectant for hand hygiene practices therefore ingestion is strictly prohibited. To the best of our knowledge, the toxicology profile of 1-propanol has remained unchanged, therefore it can be postulated that the warning on 1-propanol can be seen as an effort to prevent/reduce the health-associated effect due to misuse rather than a side-effects for hand hygiene practices during this heightened period where hand sanitizers are readily available and used.

Currently, there is no established scientific/clinical evidence to suggest that adverse effects associated with alcohol (ethanol, isopropanol nor 1-propanol) can be achieved either through skin absorption or inhalation by the sole action of using hand sanitizer for hands, even at the high frequency used by healthcare workers in a healthcare setting (refer to reference 8).

“It is prudent to remain vigilant but not overly concerned…”

1-propanol - a friend or foe in hand sanitizer?
The approach from FDA to ‘weed’ out rogue hand sanitizers is a welcomed move in this COVID-19 where the focus should be placed on pandemic management rather than fraudulent products. It is prudent to remain vigilant but not overly concerned prior to announcement from the individual national health authorities which will assess and advise their stance on 1-propanol against these FDA warnings. Meanwhile, it is advisable to use hand sanitizers from recognised infection control manufacturers/sources to ensure that the correct hand sanitizer is being used in this period of COVID-19.