LEVEL 1
Ingredients & Evidence
"Clinically tested," "scientifically proven," "dermatologist recommended" — cosmetic advertisements are filled with words designed to inspire trust. When you see these phrases, it's easy to feel reassured that it must be a legitimate product.
But let's pause and think. What exactly does "clinically tested" mean? Can you really trust those results?
First, it's important to know that there is no legal definition for the phrase "clinically tested" in cosmetics. While pharmaceutical clinical trials have strict rules, for cosmetics, what qualifies as a "clinical test" is ambiguous. Even having 10 people try a product and collecting their impressions could potentially be called a "clinical test." What matters is not the phrase "clinically tested" itself, but the substance of the testing behind it.
Scientific evidence has levels of reliability. The lowest is in vitro (test tube experiments). These involve applying ingredients to cells in a dish and observing the response. Numbers like "200% increase in collagen production" usually come from this level. However, conditions in a test tube are completely different from actual skin. The next level is in vivo (living body experiments). These involve applying products to actual human skin and measuring changes. The most reliable is RCT (Randomized Controlled Trial). This method randomly divides subjects into groups, includes a control group (placebo), and verifies the effect.
Another critical factor in judging a test's reliability is the number of subjects (sample size) and the test duration. Even if a product claims "users felt an effect," whether that was a 2-week study of 10 people or a 3-month study of 200 people makes a huge difference in reliability. Generally, to properly evaluate cosmetic effectiveness, at least 30 subjects and a test period of 8 weeks or more is considered desirable. Also, be cautious of numbers like "92% of users were satisfied." These are subjective impressions, which differ from objectively confirmed effects measured with instruments.
Another thing to remember is that research data on an ingredient and the effectiveness of a product containing that ingredient are not necessarily the same. For example, even if research says "Vitamin C has brightening effects," that is under specific concentrations and conditions. How much is actually formulated in the product, whether stability is maintained, and whether it's in a form that reaches the skin — all of these affect the outcome dramatically. Judging by ingredient name alone is like judging a dish's taste by looking only at the ingredients without the recipe.
You don't need to be suspicious of everything, but keeping these three perspectives in mind will significantly improve your skincare choices. First, "What was the test conducted on?" (test tube? animals? humans?). Second, "How many people, for how long?" (sample size and duration). Third, "Who conducted it?" (an independent institution or the manufacturer itself?). Brands that disclose this information demonstrate integrity by that alone. Moving from "it seems good somehow" to "choosing with evidence" — that one step will transform your skincare.
