Much Ado About Nothing: Cosmetics Testing with a Placebo

By: Johann W. Wiechers, PhD, JW Solutions

Posted: February 23, 2009

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Since that time, every properly performed and valid clinical study must be placebo-controlled. In addition, it must be performed double-blind so that both the investigator and the subject do not know which treatment is administered, to eliminate any form of bias. This non-bias allows investigators to be completely sure about the true biological effects of a treatment, and it does not confuse the data by allowing a suggestive component to play any role.

Henry K. Beecher, in his 1955 paper “The Powerful Placebo,” attributed nearly 30% of overall therapeutic benefits to the placebo effect. Although the paper published in the Journal of the American Medical Association described medicinal research, in cosmetics, suggestion is definitely and deliberately a part of the equation.

Recently, I was called in as an expert witness for a case where the cosmetic effects of a product were measured. Bold claims were made that were fully justified by the data. It was argued that the study results were not valid because the test was performed on untreated skin instead of against placebo. Was this proper science or not? This is an impossible question.

The starting position for a clinical cosmetic efficacy trial is always the cosmetic claim that the cosmetic company wants to make. If they claim that the product is better at providing X than the leading product on the market, then they need to test it against that product and measure the development of X in both cases. If they claim that their active ingredient is causing X, as is often done by suppliers, then they should test it against the placebo so that the only difference between the active formulation and the placebo formulation is the active ingredient.

However, if the claim is that the complete formulation is causing X, then X should be tested with and without the use of the product for which the claim is made. In other words, it should be tested against nothing; or if the company wants to make things more difficult, it should be tested against the current usual routine of the volunteers (without defining or describing it). This is exactly what some companies do not understand. They think that every product should be tested against a placebo; i.e. the same formulation without the active ingredient, irrespective of the circumstances (read the claim). Understandable but wrong.