New Developments in OTC Acne Treatment
The over-the-counter (OTC) acne market is rapidly expanding. According to the Consumer Healthcare Products Association, consumers spent approximately $607 million on OTC anti-acne products in 2017.
As the cost of prescription acne treatments and their availability decreases now that most insurance companies require prior authorization for them, more skin care companies are entering the OTC acne market. With a relatively low cost and considerable mark-up, acne products can be quite profitable for manufacturers and dermatology practices.
Acne products are unique, however, in that many are considered OTC drugs because they make treatment claims based on monographed ingredients. Acne products listing an active ingredient on the back of the packaging are regulated by the FDA as OTC drugs. The currently used monographed ingredients include: benzoyl peroxide, salicylic acid, and sulfur. These ingredients can only be used singly and not in combination, hindering their effectiveness.
There are other ingredients, such as botanicals, minerals, vitamins, probiotics, and prebiotics, that are entering the acne market, but no treatment claims can be made since these substances are not monographed.
Benzoyl peroxide is one of the most effective and most commonly used active ingredients in OTC acne preparations. Twenty-three percent of individuals aged 13 to 27 years have used an OTC benzoyl peroxide product.1 Benzoyl peroxide is manufactured by reacting sodium peroxide with benzoyl chloride to yield benzoyl peroxide and sodium chloride. It is a highly reactive substance capable of producing DNA strand breaks2; however, no correlation has been shown between benzoyl peroxide use and skin cancer in humans.
Current trends in benzoyl peroxide formulation have focused on the use of less irritating hydrogel formulations and smaller particle size benzoyl peroxide.3 Raw benzoyl peroxide is a particulate that must be solubilized into solution. Only the benzoyl peroxide that touches the skin surface is active in the killing of Propionibacterium acnes. Larger particles yield higher concentrations in the formulation, but most of the benzoyl peroxide does not touch the skin. Smaller particle size allows better skin coverage with less irritation, since the concentration is reduced. It is possible to create a 2.5% benzoyl peroxide formulation with equal efficacy to a 10% benzoyl peroxide formulation based on skin contact with the active.
Benzoyl peroxide is problematic, however, as it can cause allergic contact dermatitis in between 1% and 2.5% of consumers who use it, resulting in redness, swelling, oozing, and pain.4 Benzoyl peroxide can also bleach clothing and hair. This has led to a renewed interest in salicylic acid.
The other major active ingredient in OTC acne treatments is salicylic acid, which is used in concentrations of up to 2%.5 It is a ß-hydroxy acid where the OH group is adjacent to the carboxyl group. Salicylic acid may be less effective than benzoyl peroxide in treating acne, but it is also less irritating and less allergenic.6 Salicylic acid has seen renewed popularity in hypoallergenic acne treatments, spot acne treatments, and acne treatments for mature individuals where benzoyl peroxide would cause excessive irritation.
The least drying and irritating monographed acne active is sulfur.7 It is a yellow, nonmetallic element that has been used for centuries to treat various dermatologic conditions. The mechanism of action for sulfur is not totally understood, but it is thought to interact with cysteine in the stratum corneum, causing sulfur to transform into hydrogen sulfide. Hydrogen sulfide in turn degrades keratin, producing the keratolytic effect.8 It is used in concentrations of 3% to 8%, but has a characteristic foul odor and yellow color. The new development of decolorized, deodorized sulfur has increased its popularity, especially in acne spot treatment formulations for mature individuals.
Nonmongraphed Treatments on page 2