Hyperpigmented lesions, whether they are solar lentigo, freckles, or Melasma, are the source of frequent complaints by cosmetic patients. Cosmetic patients develop postinflammatory hyperpigmentation after chemical peels, laser treatments, or even after a bout of acne. Although there are many product choices available, the number of effective agents to treat hyperpigmentation disorders is relatively small. Unfortunately, most of these agents require months of use for improvement to be seen.
Hydroquinone (HQ) is used in over-the-counter (OTC) products (2% concentration or less); prescription drugs (4%), to produce skin lightening. For many years, HQ has been the main treatment modality for postinflammatory hyperpigmentation and melasma.
HQ is currently available as OTC in 2% concentrations and by prescription in 4% concentrations. Numerous concerns about the safety of HQ have emerged in recent years.
Aloesin is naturally derived from aloevera. It competitively inhibits tyrosine, and it inhibits melanin production (skin pigmentation) in skin.
Arbutin helps in skin depigmentation by affecting the tyrosine enzyme. Arbutin serves as an ingredient in various cosmetic products.
More than 4000 flavonoids have been identified in leaves, barks, and flowers. Flavonoids exhibit antioxidant properties but they can also directly inhibit tyrosinase. Resveratrol induces depigmentation also. Ellagic acid seems to be more effective than kojic acid or Arbutin and it is safer that Hydroquinone.
Hydrocoumarins 4 may be effective in preventing hyperpigmentation.
Kojic acid suppresses tyrosinase activity, mainly by chelating copper. This leads to a whitening effect on the skin. When used in cosmetic products, kojic acid enhances the product’s shelf life through its preservative and antibiotic actions.
Glabridin extract has been used to treat dermatitis, eczema, pruritus, cysts, and skin irritation. Glabridin is used in skin lightening products because it inhibits tyrosinase activity. Topical applications of 0.5% Glabridin have also been demonstrated to inhibit UVB-induced pigmentation. In Europe, licorice extract is widely used as an anti-inflammatory agent. Forms of licorice extract have been incorporated into skin care products to prevent inflammation.
Emblica in an extract from the edible phyllantus Emblica fruit and is thus 100% natural. Emblica combines all the important properties required for a skin lightening ingredient. Emblica is thought to have efficacy comparable to Hydroquinone and Kojic acid.
Niacinamide, also known as nicotinamide, is the biologically active amide of vitamin B3. Niacinamide exhibit anti-inflammatory, antioxidant, and immunomodulatory properties. Significant effects on hyperpigmentation have been demonstrated by a 5% Niacinamide formulation. The effects on pigmentation have been shown to be reversible.
Soy has Depigmenting activity; it has a capacity to prevent UV-induced pigmentation and lightening of pigmented spots. Soy use results in the improvement of skin tone, and additional photo aging characteristics, soy can cause significant improvement of mottled pigmentation, blotchiness, dullness, fine lines and improve the overall texture, overall skin tone, and overall appearance.
Soy contains isoflavones, which have antioxidant properties and have been found to confer cancer-preventing benefits.
Azelaic acid is useful adjunct in the treatment of postinflammatory pigment alteration. Azelaic Acid has been reported to be even more effective than topical HQ for patient with melasma, without the latter’s side effects. Azelaic acid is an excellent alternative for patients who cannot tolerate Hydroquinone.
Mequinol is a substrate to tyrosinase and acts as a competitive inhibitor of melanogenesis. Notable, 2% Mequinol & with 0.01% tretinoin has been proven to be effective in the treatment of solar lentigines.
Mon benzyl ether of hydroquinone is the substance used to cause permanent depigmentation of normal skin. It is often used in vitiligo patients to permanently depigment the skin surrounding depigmented areas when repigmentation is not feasible and the depigmented areas are disfiguring.