Skin Exfoliation: Does Pain Equal Gain? The Science behind this Question: by Dr. Diana Howard Lactic acid and glycolic acid are the front-runners in the world of alpha hydroxy acid (AHA) exfoliation. So, which ingredient works best to reveal a newer, fresher you? Independent research studies on AHAs have determined that: Glycolic acid, the smaller molecule of the two, penetrates the skin more readily than lactic acid, and as a result is more irritating to the skin. The activity of both AHAs is controlled by the pH of the solution: Optimum activity is a pH 3.0-3.2. Anything lower will damage and irritate skin. Scientific studies have demonstrated that when one compares lactic acid to glycolic acid, lactic acid stimulates cell turnover and cell renewal at a higher rate than glycolic acid and with less irritation! (Stimulating cell renewal and cell turnover rates is the immediate and long term benefit of using alpha hydroxy acids.) Unlike glycolic acid, lactic acid has added benefits: It hydrates the skin, increases natural barrier lipids in the epidermis and helps lighten hyperpigmentation (age spots). So why do professionals and consumers believe glycolic acid is the preferred AHA to user? Unfortunately, people often equate irritation with efficacy. Just because glycolic acid is more irritating does not mean it is more efficacious. In this case, pain does not equal gain. The Skin Care Expert’s View of the Question: by Annet King Over-exfoliation is one of the most common “skin-mishaps” professionals see among consumers today, which leads to sensitization, inflammation, accelerated aging, and an increased susceptibility to UV damage. Before you scrub, take skin condition into consideration: Oily/Breakout-prone skin: Choose non-abrasive hydroxy acid exfoliants gently dissolve dead cells while delivering purifying, oil-absorbing benefits. Salicylic acid, clays, sulfur, and soothing lavender and aloe are friends to your skin. Steer clear of physical scrubs! Sensitive skin: Choose gentle, superfine powders that activate with water. Key ingredients include brightening rice bran, phytic acid, and micro-exfoliating (milder, yet effective) fruit enzymes. Aging, dry, lackluster skin: Choose a warming skin polisher that helps drive age-fighting ingredients into the skin. Also look for combined physical/chemical exfoliants including lactic acid and silica with skin-shielding vitamins A, C, and E, white tea, and licorice. Want to read more? Subscribe to one of our monthly plans to continue reading this article.