What does the term, "clinically proven" mean when applied to a beauty product by its company? It's not clear what laws, if any, apply to such claims. Because there's no standard to be satisfied, the "clinically proven" label is almost always fairly meaningless. Usually, some type of study has been performed on the product, but specifics vary greatly.

A recent study of a drug "clinically proven" to protect your skin from the sun is a lesson in how this term is used and misused and what consumers should be on the lookout for when reading such claims.

... [F]our of the ten authors are employees of the company that makes the pill, that a fifth author was an employee at the time of the study...

Scientific studies rarely prove a cause and effect relationship. More often they find a relationship, a correlation. If people who are overweight are more likely to be seen in the emergency room for a heart attack, that's a correlation; it doesn't prove that weight caused the attack, but it does signal some kind of relationship. See our discussion, Well Informed: What Is Good Health Information to understand how the strength of these relationships is determined.

Sun Sensitivity is a nutritional supplement, a pill available in Europe and South America but not yet available in the United States. It contains lycopene, beta-carotene and a probiotic (Lactobacillus johnsonii). Lycopene is a red pigment found in tomatoes and beta-carotene is an orange pigment found in vegetables such as carrots.

According to the manufacturer, Sun Sensitivity is clinically proven to protect your skin from harmful UV rays while leaving you with a nice tan.

The manufacturers tested the effects of the pill on 139 adult women. Some women took the pill for 10 weeks while others did not. Separately, groups were exposed to mild artificial ultraviolet radiation, stronger UV radiation designed to simulate sunlight or to actual sunlight during the course of a summer and beyond.

Those who took the pill and were exposed to mild UV showed less buildup of inflammatory skin cells. Those who took the pill and were exposed to simulated sunlight required about 20% more UV radiation to cause sunburn and appeared to tan better than women with similar UV exposure who did not take the pill. And women who took the pill and then sun bathed as they normally do over the summer were examined by company-selected dermatologists who reported that the pill had been beneficial to their skin.

This is hardly proof, but taken at face value, the studies suggest that the pill may be beneficial to a user's skin. And these studies were sufficient to form the basis of a report published online by the British Journal of Dermatology on June 9, 2010, which stated on the first page that "the results support the use of the supplement."

This statement was later removed from the report. And statements that four of the ten authors are employees of the company that makes the pill, that a fifth author was an employee at the time of the study and that two other authors received consultancy fees were added.

The journal's editor has said that the original report contained no conflict of interest statement because "the authors stated very clearly that there was no conflict of interest." The original report did list the places of employment of all authors. It just didn't note the potential conflict of interest that this employment may have caused.

The report still says that the tanning pill increases the threshold for sunburns and "represents a complementary strategy to sun avoidance and sunscreen use for a global approach to photoprotection."

A major objection to the report's conclusion was because of the natural sunlight study. This was the largest of the three studies, with 80 women taking part. But results were never compared between women who took the pill and those who took a placebo pill. Instead, the study only looked at before and after skin differences within each group. And the differences were noted by the examinations of company-selected dermatologists.

Because of the tremendous amounts of money a product may earn, there is little question that having a company run studies on the products that it markets has some effect on the study results. What is hotly debated among researchers and the publishers of journals is whether financial conflicts of interest are altering study results and whether or not company-run studies are intrinsically believable. Most journals try to clearly list any potential conflicts of interests of the researchers in each article published.

Researchers give more credence to studies performed by less interested parties.

To the consumer, this basically comes down to whether company studies on their products are believable or not. When Sun Sensitivity is marketed in the U.S., it will simply be one more product whose effectiveness is being debated. But it's unlikely that the product will have been clinically proven to do anything.