Evidence (or Lack Thereof) Behind Retinoids

Many over-the-counter (OTC) cosmetic products contain retinoids and are promoted (advertised) as anti-aging products.  This article (first reference below) in the February issue of the Aesthetic Surgery Journal is a review of the evidence behind retinoids in cosmeceutical products.  It turns out there isn’t much.

First, let’s begin with some definitions:

Retinoids include Vitamin A and its derivatives which may be either natural or synthetic.

Cosmeceutical products are formulations which are not classified as prescription medications. 

Retinoids which are prescription medications include tretinoin, isotretinoin, alitretinoin, tazarotene, and adapalene.  Because they are classified as prescription medications, these do not qualify as cosmeceuticals.

This is an important distinction as there is a large body of evidence to support tretinoin in the treatment of photoaging.  This article focused on the cosmeceutical retinoids.

The article looks at retinyl-acetate and retinyl-palmitate, both vitamin A ester derivatives; retinol, a precursor to retinaldehyde and retinoic acid; and topical retinaldehyde.

The authors conclusions:

There is a substantial amount of evidence supporting the efficacy of tretinoin in the treatment of photoaging. The evidence supporting retinoid-based cosmeceuticals, however, remains sparse. There are a number of in vitro studies, with a smaller number of in vivo studies. Based on the hierarchical levels of evidence (with well-designed, randomized, controlled trials providing the highest level), retinaldehyde appears to be the only retinoid-based cosmeceutical to be effective in the treatment of photoaging. A large, randomized, controlled trial assessing retinyl propionate concluded that it had no significant effect on photoaging. There is evidence from a small, randomized, controlled trial showing that retinol has effects on human skin and supporting its potential as an agent against photoaging.

However, large-scale clinical studies would need to be undertaken to investigate this further. Therefore, we conclude that products containing retinyl-acetate or retinyl-palmitate are unlikely to have a significant beneficial effect, but retinaldehyde-containing cosmeceuticals have evidentiary support for their benefits in patients with aging skin. Retinol has potential benefit, but more research is needed.

 

 

 

 

REFERENCE

Cosmeceuticals:  The Evidence Behind the Retinoids; Aesth Surg Journ Vol 30, No 1, February 2010; Babamiri, Kajal MD, Nassab, Reza MBChB

Clinical Review: Topical Retinoids; Medscape article, December 2003; Sheri L. Rolewski

Retinoids: Progress in Research and Clinical Applications; Plastic and Reconstructive Surgery. 98(1):180, July 1996; Ship, Arthur G.

Treatment of Photodamaged Skin with Topical Tretinoin: An Update; Plastic and Reconstructive Surgery. 102(5):1672-1675, October 1998; Heffel, Dominic F.; Miller, Timothy A.

Cosmetic Dermatology: Principles and Practice; Plastic and Reconstructive Surgery. 113(3):1064-1065, March 2004; Chavis, Dion D.