Yes, Neosoralen (Trioxsalen) is effective for treating vitiligo, but only when combined with Ultraviolet A (UVA) light therapy (PUVA). It works by making your skin more sensitive to light to stimulate repigmentation. Regarding the dosage, you must not self-medicate. The choice between 5mg, 25mg, or other doses depends strictly on your body weight and your dermatologist's specific phototherapy protocol. Taking the incorrect dose can cause severe skin burns or treatment failure. Please consult your dermatologist to get the precise dose and monitoring schedule required for safe and effective treatment.