Like many skin lightening products on the market, Cosmelan is directed at those with more than just simple age spots they want to get rid of, although it does claim to treat these too. As a ‘depigmentation’ product, it helps to eliminate the dark patches on the skin caused by an over-production of melanin (pigmentation). Very often people with darker skin tones suffer from this, although it can be caused simply by hormonal changes and over-exposure to the sun.
While many brands of lightener do work to a certain extent, some take longer than others, and often it is those that have a faster effect that contain harsher ingredients. The brand Cosmelan is a mixture of both safer and more controversial ingredients, the latter being Kojic Acid, Phytic acid and Azelaic acid. Kojic acid in particular is thought to be a carcinogenic, i.e. cancer-causing ingredient, and can actually cause more sensitivity to the sun in some users. Phytic acid, which is found in soy, is said to inhibit the uptake of certain minerals while Azelaic acid, often used to treat Rosacea, can result in skin irritation and burning sensations. The ingredient Arbutin, which is also in this formula, is generally deemed to be safe, and is an anti-oxidant that also helps block the formation of Tyrosinase (part of the melanin production process).
While this brand is certainly not as harsh as some on the market, it would always be recommended to test the cream on a small patch of skin first, and not proceed if any sign of irritation occurs.