However, even to the untrained eye, one type of hyperpigmentation may stand out among the rest: the “melasma mustache,” as many call it. Here, we’ll explain what causes this concentrated hyperpigmentation and what to do about it. “Although melasma can occur in men, it’s much more common in women and more common in those taking oral contraceptive pills and during pregnancy,” board-certified dermatologist Rebecca Marcus, M.D., tells mbg. Clinical studies1 show that UV radiation is the most common initial trigger of melasma, as well as the main factor exacerbating preexisting patches. “Even a tiny bit of sun can cause melasma to flare in those who are susceptible, and even heat, in the absence of sun, has been known to cause a flare,” Marcus says. Hormones are also a common cause of this kind of hyperpigmentation (which is why it’s commonly triggered by birth control pills and pregnancy), though it’s unclear if the upper-lip area is more frequently affected by one of these triggers or the other. However, if you are only experiencing hyperpigmentation above the lip, you may want to look into your skin care practices as well—hair removal methods included. “I believe that melasma flares in the upper-lip area are frequently triggered by hair removal. Whether laser (heat plus light) or mechanical trauma from waxing or threading, certain hair removal modalities can trigger inflammation that may lead to a melasma flare-up,” Marcus explains. So while the exact reason for the melasma mustache is still slightly unknown (especially if other patches of hyperpigmentation aren’t present), hair removal may be something to consider. If you want to lighten your melasma patches at home, mustache area included, look for brightening topicals. “Lightening agents such as tranexamic acid, hydroquinone, kojic acid, and even vitamin C can be helpful,” Marcus explains. (You could also opt for hydroquinone’s plant-based alternative, alpha arbutin.) Kojic acid, specifically, has been shown to work wonders in fading dark spots in clinical studies2. What’s more, this ingredient doubles as an antioxidant, which can enhance the brightening effect. In fact, one study3 showed that participants with melasma have also been found to have higher markers of oxidative stress when compared to healthy volunteers—so the antioxidant boost in kojic acid may be even more beneficial than you think. Kojic acid isn’t quite as popular as vitamin C in the world of skin care products (as of now); however, the Multi-Bright Tranexamic Acid 5% Serum by Naturium is a kojic acid winner for skin brightening. According to the reviews, it’s A+ for melasma patches in particular. A healthy reminder: “Sunscreen is an absolute must, as even a small amount of UV exposure can cause melasma to flare or rebound after treatment,” Marcus says. In other words: All your at-home work and in-office treatments will go to waste if you don’t protect your skin afterward.