Tretinoin precursors

Some commercial creams have interesting formulations with AHAs (to enhance penetration of the other active products), tretinoin precursors, lactic acid, extracts of Morus Alba and kojic acid, combined with Transcutol , an adjuvant that concentrates the active products near the basal layer and the melanocytes. 

Retinol tretinoin precursor, helps drain the piloseba-ceous units... 

Either the applicator provided with the product or the point of a 30G1/2 needle should be used to limit the action precisely to the head of the comedone. In 95% of cases, comedolysis is achieved. Very large macrocomedones (>2 mm in diameter) can benefit from careful infiltration of Easy TCA or Easy Phytic solution into the center of the comedone. Post-peel care, which is very important, consists in avoiding comedogenic cosmetics, having the skin cleansed professionally once a month, and applying an antiacne cream containing AHAs, tretinoin or precursors, disinfectants, anti-inflammatories, tea-tree oil, etc." once or twice a day. For details of this treatment, see Chapter 15. 

Topical treatments for melasma usually include tyrosinase inhibitors, with or without tretinoin or one of its precursors. Azelaic acid is also a viable treatment option. A corticosteroid can be combined with it to counter any potential active inflammation. Lasers, intense pulsed light (IPL), dermabrasion and microdermabrasion have also been suggested, but often cause post-inflammatory hyperpigmentation. TCA can be an excellent treatment for melasma it eliminates the melanin stored in the papillary dermis and epidermis (Figure 13.8). Mesotherapy has been recently reputed as an effective treatment of melasma. ... 

Easy TCA , Unideep (TCA) and Lip Eyelid (phenol) can all be used as treatments for freckles, although phenol will generally not be used as the TCA can get rid of them by itself. Other treatments have been suggested. As freckles grow darker on exposure to UV rays, using a sunscreen helps to lighten them. Tyrosinase inhibitors, antioxidants, and tretinoin and its precursors can be used in conjunction with the peels to improve or prolong results. 

At the same doses, tretinoin is more effective than retinol, but it is also more irritating to the skin. Appropriate doses of retinol or retinaldehyde can be just as effective as tretinoin, without being irritating. Keratinocytes have the necessary enzyme arsenal to convert these precursors into retinoic acid, the active molecule. 

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