Strontium nitrate suppresses chemically-induced sensory irritation in humans

Skin care products are complex formulations that may cause sensory irritati on symptoms, characterized by stinging, burning, and itching. Substances ca pable of counteracting sensory irritation are of great practical interest. Strontium salts have been demonstrated to inhibit sensory irritation and in flammation when applied topically. In this double-blind study, we evaluated the efficacy of strontium nitrate in reducing chemically-induced skin sens ory irritation in 8 subjects. In a random order, 20% strontium nitrate in 7 0% glycolic acid (pH = 0.6) (mixture) was applied to the volar aspect of th e forearm and a positive control (70% glycolic acid, pH = 0.6) to the contr alateral forearm. The irritation sensation was evaluated each min for the f irst 20 min after topical application using a scale from 0-4. The duration of the irritation sensation in min was also recorded. Strontium nitrate mix ed with glycolic acid, in comparison with glycolic acid alone, markedly (p< 0.01) shortened the duration of the irritation sensation from 24.4+/-4.1 (m ean+/-SEM) min to 8.9+/-3.7 (mean+/-SEM) min, and significantly (p<0.05) re duced the mean magnitude of the irritation sensation at all time points (ov erall). The study demonstrated that strontium nitrate potently suppresses t he sensation of chemically-induced irritation.