Question: Which ingredients in beauty products should we steer clear of?
Dr. So: There are a lot. First off, some products in the market contain tretinoin in higher concentrations. These products aren’t well-regulated. Patients end up using them on their own without the advice of a physician, and end up burning their skin. Since they’re ill-advised and don’t protect their skin from the sun, they end up with melasma-like pigmentation on the face. In short, tretinoin is a good product, but you have to use it under the supervision of a physician.
Second, there are certain products containing mercury that can whiten the skin fast—really fast. But mercury is toxic to the body.
Steroids can also lighten the skin. Topical steroids constrict the blood vessels, which gives you lighter-looking skin. In actuality, the skin doesn't lighten at all. The proper way to lighten the skin is to reduce its melanin pigment, not to constrict the blood vessels. Patients who use vessel-constricting products end up having stretch marks eventually. Then, they have stretch marks to contend with, and stretch marks are forever there.
To an extent, hydroquinone can also be harmful if used over a long period of time because if melanin-producing cells are all gone, you don’t have melanin to protect your skin. Melanin isn’t our enemy; it helps us protect our skin from serious diseases, like cancer. For example, in darker-complexioned Asians, skin cancer is less common compared to patients with red hair, who are really white.