{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T02:24:52Z","timestamp":1792463092689,"version":"4.5.0"},"reference-count":56,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,4,10]],"date-time":"2018-04-10T00:00:00Z","timestamp":1523318400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>AHAs are organic acids with one hydroxyl group attached to the alpha position of the acid. AHAs including glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid are often used extensively in cosmetic formulations. AHAs have been used as superficial peeling agents as well as to ameliorate the appearance of keratoses and acne in dermatology. However, caution should be exercised in relation to certain adverse reactions among patients using products with AHAs, including swelling, burning, and pruritus. Whether AHAs enhance or decrease photo damage of the skin remains unclear, compelling us to ask the question, is AHA a friend or a foe of the skin? The aim of this manuscript is to review the various biological effects and mechanisms of AHAs on human keratinocytes and in an animal model. We conclude that whether AHA is a friend or foe of human skin depends on its concentration. These mechanisms of AHAs are currently well understood, aiding the development of novel approaches for the prevention of UV-induced skin damage.<\/jats:p>","DOI":"10.3390\/molecules23040863","type":"journal-article","created":{"date-parts":[[2018,4,10]],"date-time":"2018-04-10T13:06:08Z","timestamp":1523365568000},"page":"863","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":160,"title":["Dual Effects of Alpha-Hydroxy Acids on the Skin"],"prefix":"10.3390","volume":"23","author":[{"given":"Sheau-Chung","family":"Tang","sequence":"first","affiliation":[{"name":"Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan"},{"name":"Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien 97004, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jen-Hung","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan"},{"name":"Department of Dermatology, Buddhist Tzu Chi General Hospital, Hualien 97004, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1177\/109158189801700101","article-title":"Final report on the safety assessment of glycolic acid, ammonium, calcium, potassium, and sodium glycolates, methyl, ethyl, propyl, and butyl glylates, and lactic acid, ammonium, calcium, potassium, sodium, and TEA-lactates, methyl, ethyl, isopropyl, and butyl lactates, and lauryl, myristyl, and cetyllactates","volume":"17","author":"Andersen","year":"1998","journal-title":"Int. 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