BackgroundTretinoin is considered the benchmark prescription topical therapy for improving fine facial wrinkles, but skin tolerance issues can affect patient compliance. In contrast, cosmetic antiwrinkle products are well tolerated but are generally presumed to be less efficacious than tretinoin.ObjectivesTo compare the efficacy of a cosmetic moisturizer regimen vs. a prescription regimen with 0·02% tretinoin for improving the appearance of facial wrinkles.MethodsAn 8-week, randomized, parallel-group study was conducted in 196 women with moderate to moderately severe periorbital wrinkles. Following 2 weeks washout, subjects on the cosmetic regimen (n=99) used a sun protection factor (SPF) 30 moisturizing lotion containing 5% niacinamide, peptides and antioxidants, a moisturizing cream containing niacinamide and peptides, and a targeted wrinkle product containing niacinamide, peptides and 0·3% retinyl propionate. Subjects on the prescription regimen (n=97) used 0·02% tretinoin plus moisturizing SPF 30 sunscreen. Subject cohorts (n=25) continued treatment for an additional 16 weeks. Changes in facial wrinkling were assessed by both expert grading and image analysis of digital images of subjects’ faces and by self-assessment questionnaire. Product tolerance was assessed via clinical erythema and dryness grading, subject self-assessment, and determinations of skin barrier integrity (transepidermal water loss) and stratum corneum protein changes.ResultsThe cosmetic regimen significantly improved wrinkle appearance after 8 weeks relative to tretinoin, with comparable benefits after 24 weeks. The cosmetic regimen was significantly better tolerated than tretinoin through 8 weeks by all measures.ConclusionsAn appropriately designed cosmetic regimen can improve facial wrinkle appearance comparably with the benchmark prescription treatment, with improved tolerability.

Glucosamine has been reported to inhibit melanin production in melanocyte culture. It thus has a potential to reduce hyperpigmentation via topical use. Due to stability limitations of glucosamine, we chose to clinically evaluate the stable derivative N-acetyl glucosamine (NAG). Based on in vitro Franz cell testing, NAG is a good skin penetrant. In an 8-week, double-blind, placebo-controlled, left-right randomized, split-face clinical test, topical 2% NAG reduced the appearance of facial hyperpigmentation. In a second clinical study involving the topical combination of 2% NAG with 4% niacinamide, an agent previously shown to be clinically active, the effect on hyperpigmentation was greater. Both of these agents are well tolerated by the skin. This high tolerance coupled with relative ease of formulation and stability in solution make NAG, especially in combination with niacinamide, a suitable cosmetic ingredient for use in skin care products dealing with issues of skin hyperpigmentation.

The combination of 5% niacinamide and 1%N-undecylenoyl phenylalanine is an effective anti-aging technology for use on facial skin.