Adverse reactions in toners include transient contact irritation, contact allergy, and sensitization. Contact allergy is most often seen with more pharmacologically complex products, such as those containing multiple botanical extracts and penetration enhancers (27). Propylene glycol is often used as a humectant and sometimes as a solvent in toners. It is approved for use in concentrations up to 50% by the CIR (28), but caution is advised in using it above 10% as it can act as a penetration enhancer and cause irritation which, in patch testing, is often confused with comedones. Although tea tree oil is not recognized by the FDA as an anti-acne, antiseptic or antibacterial active ingredient, it is found in many antiacne and oily skin toners. It also has a distinctive odor, and recently there have been several reports on the allergic, sensitization, and irritation potential of tea tree oil (18-21,29). COLIPA recommended that it not be used in cosmetic products at concentrations greater than 1% (25). Increased sun sensitivity occurs from topical application of AHA-containing products. Recently, the FDA issued industry guidance for labeling these products with a sunburn alert to minimize this risk (30). Toners have very low rates of reported adverse reactions compared to other skin care products. FDA statistics for the years 1991-1994 show 7.07 reported adverse reactions to toners and fresheners per million units sold, (31) and no consumer complaints were reported from 1995-2003 (32).
Toners have a beneficial role in a patient’s skin care regimen. They reduce the appearance of pore size; exfoliate; remove or control sebum; soothe skin aggravated by the environment, dryness, or dermatological procedures, and provide a clean, refreshing skin feel. When properly formulated for skin type and skin benefits, they offer a cosmetically acceptable vehicle for delivery of ingredients used in cosmetic, cosmetology, post-cosmetic surgery, and acne treatment applications.