Evidence-based cosmetics: new trend or old hat?

Simon Singh quotes this profound observation in his recent book “Trick or Treatment” (co-authored with Edzard Ernst MD)1 which examines in the most objective possible way the many remedies and treatments proposed as “alternative medicine”. In this book, the authors introduce the concept of evidence-based medicine and randomised controlled clinical trials, which constitute the gold standard of today’s approach to the development of new pharmaceutical drugs, new therapies and medical treatments. However, instead of boring the reader with a long theoretical presentation on how clinical trials should be conducted, or how to gather evidence, Singh and Ernst start off with a fascinating story on how the principles of controlled experiments (science) slowly gained ground over traditional methods of treatment, based on hearsay, opinions, anecdotes and irrational beliefs. Stories include: how a cure for scurvy was discovered, how bloodletting (which killed George Washington) lost its hold on the medical profession, how Florence Nightingale proved that hygiene in military hospitals saved more lives than amputation and how the connection between smoking and lung cancer was established against all the then-current medical opinion (and against political and commercial pressure). What does this have to do with the field of cosmetics, you may ask? Cosmetic products should not and do not ordinarily claim to treat, cure or prevent any disease or damage to the tissue of our bodies. Nevertheless, as the pressure for constant innovation increases, as claims designed to entice the consumer to purchase the latest anti-ageing formulas are becoming more and more daring, and as we continue to hear about the growing market of “cosmeceuticals” (also called “active cosmetics”, “dermocosmetics” etc.), the need to adopt the methods of evidencebased medicine and its philosophy for cosmetic purposes becomes easier to see. Of course, cosmetic products (which includes all categories of personal care, such as toiletries, skin care, body care, hair care, make-up and colour cosmetics) have, over the last 50 years come a long way, and claims such as: “The actives immediately penetrate deeply into the skin and clean and disinfect the skin from both inside and outside”, seen on an ointment from the 1950s, or: “Skin protecting vitamins that regenerate the skin and stimulate blood circulation”, which was still seen in the 1970s have been replaced by more subtle, less easily debunked statements. However, can we say that cosmetic claims of today as suggested by advertising and other promotional material are always based on the principles of evidence gathered in well-designed and pertinent studies? Is cosmetic research indeed a science? What should the criteria for evidencebased cosmetics be? Those are the topics we shall review in the following paragraphs.

A bit of history

Cosmetic products of all kinds have been used for thousands of years, all around the world. However, not until the second half of the 20th century did the aspects of safety and efficacy become major concerns; and still today, the authorities’ interest in this industry is by far higher for assuring the absolute safety of cosmetics than for checking wonderful sounding promises of efficacy. This situation may not last forever, as a trend in Asia has shown: in Korea any anti-wrinkle claim turns a formula into a “functional cosmetic” for which certain government imposed rules have to be obeyed. The Japanese quasi drug sector of products is also about to include new categories of clearly cosmetic claims for which pre-market registration is necessary. Will European and US regulations remain behind for long?