SKINIPEDIA - Skin Encyclopedia Studies: Human Skin Texture

Fine Skin Lines, Wrinkles & Human Skin Texture - a study by P&G Beauty


RETINOIDS


Retinoids are natural or synthetic substances derived from vitamin A and its oxidized metabolites. These agents play an important role in the regulation of cell proliferation, differentiation and epidermal remodeling, among other functions. Topical retinoids have demonstrated a high degree of efficacy against acne and psoriasis, as well as in preventing or repairing aspects of photodamage, such as fi ne lines, wrinkles and pigmentation problems. However, the clinical and histological benefits of some of these agents are limited by the high degree of side effects, including dryness and mild-to-moderate skin irritation that may persist over the course of topical use, and the associated teratogenic effects. In recent years, new synthetic derivatives of vitamin A that have been developed for use on human skin minimize cutaneous irritation and other unwanted effects.

Clinical trials comparing retinol to retinyl esters suggest that retinyl propionate, the propionic acid ester of retinol, delivers skin benefi ts that are similar to using retinol (e.g., improvement in appearance of wrinkles and pigment spots) but with less irritation. Because of the skin’s enhanced sensitivity to sunlight when using retinoids, adequate sun protection must be factored into treatment. A 12-week study evaluated the use of retinol and retinyl propionate both co-applied with sunscreen. Those using retinyl propionate and sunscreen showed a signifi cant reduction in the appearance of wrinkles and sunspots with no irritation.


Conversely, the retinol-sunscreen combination appeared to exacerbate skin irritation and lessened the skin benefi ts. Retinyl propionate appears to offer dermatologists a milder, more tolerable form of retinoid that can improve the look of photoaged skin, while guarding against additional sun damage and irritation.

Niacinamide

Topical niacinamide, a water-soluble derivative of vitamin B3, provides a host of dermatological therapeutic benefits. Clinical research provides grow ing evidence for its positive eff ects on skin health, from helping maintain barrier integrity to diminishing the signs of aging, including:

(1) reducing fine lines and wrinkles;
(2) reducing texture problems by diminishing the appearance of pores and
(3) improving skin tone by reducing the appearance of hyperpigmentation, skin yellowing and red blotchiness.

Niacinamide is also well-tolerated and compatible with other anti-aging technologies, making it an ideal choice for skin care. In fact, it has recently been shown that the use of niacinamide-containing moisturizer during topical tretinoin therapy mitigates the severity of side eff ects and augments the treatment response.

The effects of niacinamide on skin cells in culture have been explored extensively. Niacinamide has been shown to be a key player in the normalization of age-associated depletions of nicotinamide coenzymes. This is of particular importance for aged skin since systemic and intracellular concentrations of the nicotinamide coenzymes NADH and NADPH decline with age in human and animal models. These cofactors are critical drivers of both catabolic and anabolic processes within cells including the production and maintenance of the dermis. In particular, niacinamide supplementation has been shown to stimulate collagen synthesis in human dermal fibroblasts, an effect that would be of particular signifi cance in aged and
photodamaged skin.

Multiple clinical studies have demonstrated the positive eff ects of niacinamide- containing moisturizers on the
appearance of wrinkles and fi ne lines in aging skin. In one, a 12-week randomized, split-face trial, 50 female subjects applied blind-coded product followed by image analysis. Signifi cant improvements were seen in several facial parameters including appearance of fi ne lines and wrinkles (p=0.06 at week 8 and 0.0005 at week 12).

In another study, 40 female subjects applied blind-coded products in a split-face design for 12 weeks. Significant
improvements in skin texture including fi ne line appearance were observed in niacinamide-treated skin
at both four and 12 weeks of treatment (p<0.1, <0.05, respectively).


Human Skin Texture study CONTINUES HERE.