A once-daily pill has helped restore skin color in some people with vitiligo, a condition that causes white patches to appear on the skin.The development could offer an easier treatment option, particularly for people whose vitiligo affects large or hard-to-reach areas of their body.Unlike creams applied to individual patches, the tablet works throughout the body.Vitiligo develops when the immune system mistakenly attacks the cells that give skin its color. The condition is not contagious, but its visible patches can affect people's daily lives and mental health.People with vitiligo can experience stigma, anxiety, and social exclusion. Restoring skin color is therefore about more than appearance.Current treatments include creams and light therapy. These can help return color to the skin, but often require repeated treatment over many months. Applying creams can also be difficult when vitiligo covers large areas.A UV photograph of a hand with vitiligo. (Chip Bobbert/CC BY-SA 4.0)The new study, published in The Lancet, tested a drug called upadacitinib in 614 adults and teenagers aged 12 or older.The two trials were conducted at 138 institutions in 18 countries. All participants had the most common form of vitiligo, with patches affecting both their face and body.Participants were randomly assigned to take either 15 milligrams of upadacitinib or a placebo once a day for 48 weeks. Neither the participants nor the researchers assessing their skin knew who was receiving the real drug.In the first trial, 25 percent of patients taking upadacitinib regained at least 75 percent of the color lost from their face. Only 6 percent of those taking a placebo reached the same target.The second trial produced almost identical results. The target was reached by 23 percent of patients taking the drug, compared with 7 percent of the placebo group.Color also returned to other parts of the body. In the two trials, 19 percent and 21 percent of patients taking upadacitinib regained at least half of the color lost from affected areas. Only 6 percent of each placebo group experienced the same improvement.