By the age of 25 and over the skin will exfoliate every 28 days or so. And at 30, every 40-42 days. The resulting build up of dead skin cells can leave the skin looking dull.
The year before menopause, women actually have an INCREASE in estrogen, which can lead to irregular bleeding, mood swings, and other problems.
Retinol enhances the skin's barrier function, aids in collagen production, regulates oil production, reduces skin dryness, and increases skin oxygenation. Topical steroids like cortisone will thin the skin when used for prolonged periods. Retinol will actually thicken thin skin.
Retinoids are the prototype of all Cosmeceuticals, and improves wrinkles, acne, pigments, dryness and redness.