Melanocyl Solution contains Methoxsalen 1% w/v, a photosensitizing agent primarily used in the management of vitiligo and psoriasis. Methoxsalen belongs to the class of psoralens and acts by intercalating into DNA, thereby enhancing the skin’s sensitivity to ultraviolet A (UVA) radiation. This mechanism facilitates repigmentation in depigmented areas by stimulating melanocyte activity when combined with controlled UVA exposure, commonly referred to as PUVA therapy. Melanocyl Solution is applied topically to affected skin regions prior to UVA irradiation, ensuring localized treatment and minimizing systemic absorption. It is indicated for patients with stable vitiligo and certain cases of psoriasis unresponsive to conventional therapies. Caution is advised in patients with a history of photosensitivity disorders, skin malignancies, or hepatic impairment. Adverse effects may include erythema, pruritus, burning sensation, and, rarely, phototoxic reactions. Proper dosing and timing of UVA exposure are critical to optimize therapeutic outcomes and reduce the risk of adverse events. Patients should avoid excessive sunlight exposure and use protective measures during treatment. Melanocyl Solution should be used under strict medical supervision, with periodic monitoring to assess efficacy and safety.