Zu Vitamin C kann ich nur sagen, dass es ein antioxidant ist - da ich es nicht vertrage, weiß ich nicht mehr darüber. Fruchtsäure ist ein ungenauer Begriff für BHA und AHA, eins von beiden heißt auch Glycolsäure, soweit ich weiß.
Retinol ist ein zellkommunikativer Stoff, der die Erneuerung der Haut stimuliert. Hat Paula aber auch was bei Inhaltsstoffen geschrieben:
retinol. Technical name for vitamin A. There is research demonstrating that retinol can have the same action on skin as tretinoin (a derivative of vitamin A and the active ingredient in Retin-A, Renova, Tazorac, and Avita). In skin, tretinoin is the form of vitamin A that can actually affect cell production by binding to the tretinoin receptor sites on the cell, and, therefore, retinol and retinyl palmitate must become tretinoin in the skin if they are to do the same thing. Theoretically, retinol can become tretinoin in the skin, but it is not a direct process. Retinol can be absorbed into the skin and if certain enzymes are present it could be converted to tretinoin. There is research, however, showing that retinol (and retinyl palmitate) can increase epidermal thickness and can indeed function in a manner similar to tretinoin (Sources: Journal of Investigative Dermatology, 1998, volume 111, pages 478�484, and September 1997, pages 301�305; Skin Pharmacology and Applied Skin Physiology, November-December 2001, pages 363�372; and Experimental Dermatology, February 1998, pages 27�34).
Retinol is an unstable ingredient, and therefore its packaging is of vital concern. Any container that allows the product to be exposed to sunlight and air means that the retinol will not be stable for very long, if at all, after it is opened (Source: Journal of Cosmetic Science, January-February 2001, pages 77�78). See tretinoin.
Zu Vitamin C:
vitamin C. Considered a potent antioxidant for skin (Sources: Journal of Investigative Dermatology, February 2002, pages 372�379, and June 2001, pages 853�859; and Toxicology in Vitro, August-October 2001, pages 357�362). Claims that vitamin C can prevent or eliminate wrinkling are not proven. An article in Plastic and Reconstructive Surgery (January 2000, pages 464�465) discussed the issue of vitamin C and concluded that �Vitamin C is a valuable antioxidant and protectant against photodamage that is created by sunlight in both the UVB and UVA bands�. Although oral supplementation may also be useful, topical preparations are able to deliver a higher dosage to the needed area. Topical vitamin C does not absorb or block harmful ultraviolet radiation like a sunscreen. Instead, it augments the skin�s ability to neutralize reactive oxygen singlets [free-radical damage] that are created by the ultraviolet radiation, thereby preventing photodamage to the skin. It becomes an integral part of the skin and remains unaffected by bathing, exercise, clothing, or makeup. Used appropriately, topical vitamin C is an important adjunct to the use of sunscreens, an adjunctive treatment to lessen erythema [redness] in skin resurfacing, a helpful adjunct or an alternative to Retin-A in the treatment of fine wrinkles, and a stimulant to wound healing." See Paula's article, Vitamins.