How to Evaluate A Skincare Product
Look at the Label
Analyze Your Results
Know what to look for.
The study was large. The larger the study, the more likely it is that the results are applicable to the population in general. Think of flipping a coin; the more times you flip it, the more likely you are to have gotten heads half the time and tails half the time. Many skincare studies have only five or ten participants, which is unfortunate. I give far less weight to these than to studies with thirty or more subjects.
The study was randomized. The study subjects should be randomly assigned to treatment or control groups, not “selected.” This prevents scientists from studying an anti-aging cream and putting twenty-year-olds in the “treatment” group and eighty-year-olds in the “control” group and saying the treatment group looked significantly younger after eight weeks.
The study was placebo-controlled. The placebo effect has been well-documented. However, in a placebo-controlled study, all of the patients (even in the control group) get something, so you can measure whether it was the treatment itself that was effective, and not just the perception of being treated.
The study was published in a peer-reviewed journal. While there surely are great studies conducted outside the realm of published scientific research, well-versed scientists tend to give more weight to the studies in the journals than studies in company brochures or press releases. The peer review process keeps science honest by subjecting researchers’ work to criticism from their peers. That’s why it’s hard to find “Nine out of ten women report softer skin” in the headline of a science research journal article as often as in product advertisements.
The study was done on humans, not animals or tissue samples. It can be difficult to obtain these studies, but they are the holy grail of dermatological science. The problem is that if it is believed a treatment may cause a detrimental condition, researchers would rather harm animals or tissue cultures than actual humans. It is more reasonable to look for human (in vivo) studies when you are looking for a potential benefit rather than harm. For instance, human studies have verified the benefits of niacinamide, retinoids, and sunscreen in fighting signs of aging over time.
The study tested ingredients at reasonable concentrations. One of the reasons the FDA allows parabens to be used in skincare is that the amount of parabens in products is extremely low compared with the amount of parabens tested in studies. Some of the studies that demonstrated that “parabens could cause cancer” exposed mice to 25,000 times the typical dose in a skincare product–even if some types of parabens remain in the system for three years, this is still over 1000 times the amount of parabens you would ever have in your system. Always keep dosage in mind.
The study’s results have been replicated. Quote Divine Caroline, “If one person tells you that you’re a horse, he’s crazy. If three people tell you that you’re a horse, there’s a conspiracy afoot. If ten people tell you that you’re a horse, buy a saddle.” The same goes for dermatological science: When one study touted retinol for its anti-aging properties, it was a brilliant suggestion. When retinol’s smoothing and wrinkle-fighting abilities were verified by thousands of studies, it is considered to be a gold standard by many dermatologists. In other words, repeatability equals reliability.