ALPHA HYDROXY ACIDS 245 RESULTS AND DISCUSSION During this investigation, a total of twenty-five different consumer cosmetic products obtained at stores in the Washington, DC area in 1999 were analyzed for glycolic acid and lactic acid and tested for pH (Table I). About half of the products contained glycolic acid, ranging in concentration from 2% to almost 9%, with an average concentration of 5.6%. Another half of the products contained between 1% and almost 9% lactic acid, with an average concentration of 3.7%. The pHs for both neat and diluted (1/9) products ranged from 3.2 to 9.0, with no significant difference between neat and diluted data. Most had a neat and diluted pH near 4.3. Five of the consumer cosmetic products contained a sunscreen while eight of the consumer cosmetic products contained a rec- ommendation for the use of a sunscreen on the product label. The levels of AHAs in all consumer cosmetic products tested fell below the 10% threshold recommended by the CIR. Twenty-three out of twenty-five products tested also had pHs very near or above the CIR's recommendation for minimum pH. In addition to consumer cosmetic products, seventeen professional/salon products col- lected by FDA inspectors throughout the U.S. in 2000 were analyzed for glycolic acid and lactic acid (Table II). These products were intended for professional use only. Most of these products contained glycolic acid, with concentrations ranging from 0.9% to 28.5%, with an average concentration of 10.5%. Five products contained lactic acid at an average concentration of 4.0%. The levels of AHAs in all salon products fell below the 30% threshold recommended by the CIR however, two products had pHs signifi- cantly below the recommended minimum. None of these salon products contained a sunscreen and only two of them contained a recommendation for the use of a sunscreen on the product label. The absence of chromatographic interference was evidenced by a consistent retention time and peak area for each arialyre in each analysis. R-squared values for calibration curves were typically 0.999 or better. In cosmetic product matrices, recovery of added glycolic and lactic acids ranged from 94% to 105%, with an average recovery of 99% (Table III). In the salon product matrices, recovery of added AHAs ranged from 94% to 106%, with an average recovery of 101% (Table IV). CONCLUSION All of the consumer cosmetic products and salon style products tested in this study met the CIR's recommendations for AHA concentration. Two out of a total of twenty-five consumer cosmetic products had pH values below that recommended by the CIR. Two out of a total of seventeen salon products had pH values below that recommended by the Table I Concentration of Glycolic and Lactic Acids, and pH, in Consumer Cosmetic Products Alpha hydroxy Concentration Concentration Occurrence acid avg. (%) range (%) frequency Average pH • pH • range Glycolic acid Lactic acid 5.6 1.9-8.7 13 of 25 3.9 3.3-5.6 3.7 1.1-8.7 13 of 25 4.7 3.2-9.0 Neat.

246 JOURNAL OF COSMETIC SCIENCE Table II Concentration of Glycolic and Lactic Acid, and pH, in Salon Products Alpha hydroxy Concentration Concentration Occurrence acid avg. (%) range (%) frequency Average pH • pH • range Glycolic acid Lactic acid 10.5 0.9-28.5 16 of 17 3.3 4.0 1.0-14.0 5 of 17 3.6 1.3•4.6 3.2•4.2 1Neat. Table III Recovery of GIycolic and Lactic Acids From Two Consumer Cosmetic Products Amount added I Amount added (%) (mg/ml) Amount found (mg/ml) Recovery (%) Trial 1 Trial 2 Trial 1 Trial 2 Mean GIycolic Acid Product 1 Product 2 Lactic acid Product 1 Product 2 1.53 0.523 0.546 0.539 104 104 104 1.65 0.523 0.548 0.536 105 103 104 1.57 0.537 0.525 0.504 98 94 96 1.70 0.537 0.531 0.552 99 103 101 • As a percentage of sample weight. Table IV Recovery of Glycolic and Lactic Acids From a Salon Product Amount found (mg/ml) Recovery (%) Amount added • Amount added (%) (mg/ml) Trial 1 Trial 2 Trial 1 Trial 2 Mean Glycolic acid Lactic acid 1.71 0.51 0.48 0.54 94 106 100 3.25 1.02 1.00 0.99 98 97 98 9.49 2.93 2.90 2.85 99 97 98 12.2 3.78 3.89 103 103 14.88 4.47 4.35 97 97 1.85 0.55 0.55 100 100 3.53 1.11 1.14 1.14 103 103 103 12.9 3.97 4.12 4.09 104 103 104 12.1 3.65 3.71 102 102 16.5 5.13 5.39 105 105 • As a percentage of sample weight. CIR. About half of the consumer products either contained a sunscreen (five products) or a recommendation for the use of a sunscreen (eight products). None of the salon products contained a sunscreen and only two contained a recommendation on the prod- uct label for the use of a sunscreen. The FDA plans to continue monitoring AHAs in consumer products and salon style professional products. The FDA is also continuing to assess the safety of long-term use of AHA products.