Which anti-aging ingredients actually work?

What anti-aging ingredients in your skin care cream have actually been proven to be effective? Image source: Flickr Creative Commons-RahelSharon

I recently posted on the SkinCareAddiction section of Reddit, “Skin Care Addicts: I am one of the contributing editors of CentralSkin.com, suggest any topic or section related to skin care that you would like me to write about.” My post was very well received and nihilcupio, the Redditor whose suggestion received the most upvotes, requested an article about “anti-aging ingredients and which ones have any efficacy.” I think this is a great topic, especially considering that the average American woman uses 12 skin care products per day and an average man averages 6 per day. Since each product has dozens of ingredients, one can imagine how many different unique chemical ingredients the average American puts on their skin. To clarify which of these ingredients is useful for anti-aging and which are filler/clever marketing ploys, one has to look at the evidence.

Unfortunately, few skin care ingredients are vetted with the same clinical studies that medications, like blood pressure medications, are subject to. Nonetheless, I tried finding the scientific evidence behind the marketing claims. Here is the information.

What is skin aging and what are anti-aging ingredients?

First a few words on the term, “anti-aging.” Skin aging is the end process of repetitive sun damage which leads to thinning skin, wrinkles, changes in skin pigmentation, and the development of precancerous and cancerous skin lesions. On a molecular level, UV radiation from sun generates reactive oxygen species which can damage multiple components of your skin. In addition, UV radiation activates a certain set of enzymes called matrix metalloproteinases (MMPs) which chew up your collagen and elastic fibers, the components that provide firmness and stretchibility to your skin. One of the ways that skin protects itself from this damage is to produce natural antioxidants that neutralize the reactive oxygen species. The cosmetics industry touts anti-aging creams which contain vitamins and other anti-oxidants which supposedly reverse the signs of skin aging.

Common Cosmeceutical Active Ingredients

Retinoids and Vitamin A: Naturally occurring antioxidant in the skin and one of the few proven agents that repair photodamage.

Tretinoin (brand name Retin A) is the biologically active form of vitamin A and is only available with a prescription. It has been shown to improve skin roughness, fine facial wrinkles, and mottled hyperpigmentation. Nonetheless, it is associated with the side effects of skin irritation and skin redness.

Other less potent forms of vitamin A that are available OTC (over the counter) are retinol, retinaldehyde, and retinyl palmitate.

Retinol: the best studied OTC Vitamin A product that has been consistently shown to improve photo-aged skin and fine wrinkles after 12 and 24 weeks of treatment. However, this is not compared to the clinical strength Tretinoin, which presumably has much higher efficacy.

Retinaldehyde: Some studies show that it can produce significant improvement in both fine and deep wrinkles. ​

Retinyl Palmitate: Has not yet been shown to be an effective anti-aging treatment in clinical studies, despite some in vitro studies showing that it may protect skin cells from sun damage on the protein/DNA level.

α-Hydroxy Acids (AHAs)

This class of compounds are the agents used in chemical peels. AHAs work by thinning the top layer of the skin and encouraging the process of skin exfoliation. Refer to our previous articles to refresh your memory on exfoliation and its multiple benefits . OTC AHAs include glycolic acid, malic acid, lactic acid, citric acid, and hydroxyl fruit acid. OTC topical creams may have up to 10% concentration of AHA and one would need a prescription for stronger agents. Studies have shown AHAs to be effective in reversing markers of photoaging. A clinical trial evaluation 8% glycolic acid and 8% L-lactic acid creams found that both significantly improved the severity of photodamaged skin when used over a 22-week period. A study of high concentration 25% AHA lotion showed that it thickened the top layers of the skin (both epidermis and dermis) and increased the density of skin components collagen and elastic fibers.

Ascorbic Acid

Ascorbic acid, a lso known as Vitamin C, is used in the topical format for its antioxidant properties. Studies have shown that topical Vitamin C works on the molecular level by providing protection against both UVA and UVB rays, by increasing the production of collagen, the structural component of the skin, and by reducing the inflammatory process. However, many of the studies of topical Vitamin C were only conducted on the molecular level and further clinical outcome trials need to be conducted before the anti-aging activities of topical Vitamin C can be verified.

Vitamin E

Vitamin E is an anti-oxidant which in its most biologically active form α-tocopherol has been shown to reduce and prevent sunburn and neutralize free radicals. Interestingly, topical vitamin E and vitamin C may act synergistically to protect against UV radiation when applied together. Nonethless, no studies have definitively shown that Vitamin E improves photoaged skin clinically.

α-Lipoic Acid (ALA)

α-Lipoic Acid (ALA) is a compound with anti-inflammatory properties that acts as an exfoliant. 5% ALA applied topically for 12 weeks has been shown to improve fine wrinkles and reduce skin roughness.

​ Niacinamide

Niacinamide is a form of Vitamin B3 or niacin. Niacinamide is a strong antioxidant that has been shown to improve the lipid barrier in the outer surface of your skin (stratum corneum) and thereby reduce water loss/dehydration. Topical application of niacinamide has been shown to reduce fine lines and wrinkles, eliminate hyperpigmented spots and improve skin elasticity. Topical application of glucosamine (NAG), an essential component in certain biochemical pathways, has been shown to reduce skin wrinkles and hyperpigmentation when used in combination with niacinamide.

Stay tuned for a future article where we review the efficacy of some promising new ingredients used in skin care products including flavenoids, grape seed extract, tea polyphenols and derivatives of Coffee arabica berries.

Reference:

Nolan KA and Marumur ES. Over-the-Counter Topical Skincare Products: A Review of the Literature. Journal of Drugs in Dermatology 2012 Feb;11(2):220-224.