Topical Phenylalanine
Melanocytes may still be present in long-standing (>25 years) depigmented skin of patients with vitiligo. L-phenylalanine uptake and turnover in the pigment forming melanocytes is vital for initiation of melanogenesis. Phenylalanine hydroxylase activities increase linearly with inherited skin color yielding eightfold more activities in black skin compared to white skin.

Camacho and Mazuecos performed an uncontrolled retrospective survey of a group of 193 patients (171 participants after screening) with evolving vitiligo who were treated with oral (50 or 100 mg/kg daily) and topical (10% gel) phenylalanine plus sun exposure. When the study closed, 100% repigmentation was achieved in 122 patients on the face, 35 on the trunk, and 33 on the limbs. Patients who were treated during the months of high solar radiation (and therefore also used the topical phenylalanine) achieved greater repigmentation. No side effects were reported.

Arch Dermatol. 1999; 135:216-217
Treatment of vitiligo with oral and topical phenylalanine: 6 years of experience.Click here to access the PubMed abstract

J Drugs Dermatol 2002 Sep; 1(2):127-31
Oral and topical L-phenylalanine, clobetasol propionate, and UVA/sunlight--a new study for the treatment of vitiligo.Click here to access the PubMed abstract

Mol Genet Metab 2005 Dec; 86(4):27-33
Decreased phenylalanine uptake and turnover in patients with vitiligo.Click here to access the PubMed abstract