Cysteamine hydrochloride (5%) over-the-counter Mechanism of action seems to involve inhibition of melanin synthesis pathway
Kojic acid (2%) OTC
Flutamide (1%)
Chemical peels
Microdermabrasion to dermabrasion (light to deep)
Galvanic or ultrasound facials with a combination of a topical crème/gel, either in an aestheticians office or as a home massager unit
Laser but not intense pulsed light (which can make the melasma darker)

Effectiveness
Evidence-based reviews found that the most effective therapy for melasma includes a combination of topical agents. Triple combination creams formulated with hydroquinone, tretinoin, and a steroid component have shown to be more effective than dual combination therapy or hydroquinone alone. More recently, a systematic review found that oral medications also have a role in melasma treatment, and have been shown to be efficacious with a minimal number and severity of adverse events. Oral medications and dietary supplements employed in the treatment of melasma include tranexamic acid, Polypodium leucotomos extract, beta‐carotenoid, melatonin, and procyanidin.Oral procyanidin combined with vitamins A, C, and E shows promise as safe and effective for epidermal melasma. In an 8-week randomized, double-blind, placebo-controlled trial in 56 Filipino women, treatment was associated with significant improvements in the left and right malar regions, and was safe and well tolerated.In all of these treatments, the effects are gradual and a strict avoidance of sunlight is required. The use of broad-spectrum sunscreens with physical blockers, such as titanium dioxide and zinc oxide, is preferred,  because UV-A, UV-B, and visible lights are all capable of stimulating pigment production.
Many negative side effects can go along with these treatments, and treatments often are unsatisfying overall. Scarring, irritation, lighter patches of skin, and contact dermatitis are all commonly seen. Patients should avoid other precipitants, including hormonal triggers. Cosmetic camouflage can also be used to hide melasma. See also
Linea nigra
List of cutaneous conditions

References
External links

DermNet colour/melasma