Did you know? Retinol is technically an alcohol! :o)
Through multiple double-blind, controlled clinical trials, retinol was shown to:
- Improve wrinkles on cheek, under the eyes, on the forehead and crow’s feet by inducing collagen and GAG synthesis.
- Brighten skin and lighten brown spots and mottled pigmentation.
- Increase the elasticity of the skin below the eyes and at the jaw line, as well as the skin’s overall firmness.
- Reduce skin roughness, possibly via the same mechanisms as wrinkle effacement.
Retinol is pretty unstable (though newer, more stable forms of retinol have become available) look for products in light and air tight containers. Jars and clear bottles are not recommended! Far more important is the delivery system of retinol and what other ingredients the retinol is paired with. Often you’ll see retinol products in a base of silicones as they are excellent “carriers” for this ingredient but may cause breakouts for those sensitive to silicones.
According to Paula’s Choice, naturally derived retinol comes only from animal sources, and is too unstable for inclusion in skin-care formulas.
There is limited scientific evidence for the cosmetic retinyl esters (acetate, linoleate, proprionate, palmitate) and it is thought that little is converted to the active retinoic acid form. However these esters are found in human skin and retain some of the properties of the stronger retinoids.
All studied retinoids are antioxidants, moisturising, reduce hyperpigmentation and reduce collagen breakdown. The retinyl esters have anti inflammatory properties.
Retinol actively increases collagen production and glycosaminoglycan synthesis, thickening the upper and lower layers of the skin so is considered anti ageing. It is believed to have 5% to 10% of the potency of prescription retinoic acid. In addition retinaldehyde has antibacterial and comedolytic properties so may be particularly useful in acne vulgaris.
What’s the difference between Retinal and Retinol?
Retinal has a slightly different molecular structure than retinol. They are believed to have nearly identical functions on and in skin.
Does retinol become deactivated when used in conjunction with benzoyl peroxide?
The deactivation was a concern with older retinol products, but the latest versions are able to withstand this combination. The tricky thing is some people’s skin won’t like the combination when applied at the same time, so you may need to separate application to minimize or eliminate side effects like redness or flaking.
Is retinyl palmitate the same as retinol?
In 2008, there were 1,778 cosmetic products containing retinyl palmitate in the US FDA’s Voluntary Cosmetic Registration Program, compared to 160 products containing retinol, 28 products containing retinyl acetate and 3 products containing retinoic acid. The concentration of retinyl palmitate in cosmetic products ranges from 0.1% to 10%, but is generally less than or equal to 1%.
For a comprehensive review, see this PDF.
In short, retinyl palmitate is partially hydrolyzed to retinol in the skin, and both penetrate well, especially in oil-in-water creams.
Retinol and retinyl palmitate are determined to be “safe as used” (retinol: ≤1% leave-on skin, ≤0.1% near eye; retinyl palmitate ≤2% leave on, ≤0.5% near eye).
Retinyl palmitate is more thermally stable than retinol, and is therefore frequently used as a retinoid in cosmetic products. It is however more photochemically labile than retinol, which is problematic. The addition of sunscreens such as butyl methoxy dibenzoylmethane and antioxidants such as vitamin C, vitamin E and butyl hydroxytoluene (BHT) helps increase the stability of retinyl palmitate in cosmetic formulations.
To be pharmalogically active, retinyl palmitate must be enzymatically converted in the skin to retinol, but there are multiple conversion steps for this to take place. Because of the multiple conversion steps, higher concentrations of retinyl palmitate as compared to retinol or retinal are required in cosmetic formulations to produce similar cellular and molecular changes in the skin.