An arthritis medicine may offer a new treatment option for people experiencing severe alopecia areata, after two large clinical trials found significant hair regrowth among participants taking the drug.

The medicine, upadacitinib, is an oral drug that works by blocking Janus kinase (JAK) signalling involved in the immune system's inflammatory response. Researchers investigated whether this mechanism could also help control the immune attack on hair follicles that occurs in alopecia areata.

Alopecia areata is an autoimmune condition in which the immune system mistakenly attacks hair follicles, causing hair to fall out. Because the follicles are not usually permanently destroyed, hair can potentially regrow when the immune response is brought under control.

What Did the Trials Find?

The two Phase 3 randomised clinical trials included 1,399 people aged 12 to 64, including 118 adolescents. All participants had severe alopecia areata, with at least half of their scalp hair missing at the start of the trials.

Participants received either a daily 15 mg dose of upadacitinib, a daily 30 mg dose, or a placebo for 24 weeks. Researchers assessed hair regrowth using the Severity of Alopecia Tool (SALT) score. A score of 20 or lower indicates that a person has lost no more than 20% of their scalp hair, meaning at least 80% scalp hair coverage.

By week 24, around 45% of participants taking 15 mg achieved this level of regrowth in both trials. The results were even stronger among those taking 30 mg, with 55% and 54.3% reaching the target in the two studies. By comparison, just 1.5% and 3.4% of participants receiving placebo achieved at least 80% scalp hair coverage.

Some Participants Regrew All Their Scalp Hair

The results were not limited to substantial regrowth. Depending on the dose and trial, between 13.1% and 22.5% of participants taking upadacitinib achieved a SALT score of zero, meaning complete scalp hair coverage at week 24.

The highest figure was recorded among people taking the 30 mg dose in one of the trials. Complete regrowth was virtually absent in placebo groups.

The researchers also reported improvements in eyebrow and eyelash hair among participants receiving upadacitinib. Some responses were detectable as early as eight weeks after treatment began.

Is Upadacitinib Safe?

The researchers found that the safety profile of the two doses was consistent with what is already known about the medicine, with no new safety concerns identified during the trials.

Reported side effects occurring in more than 5% of participants in at least one treatment group included upper respiratory tract infections, acne, raised blood creatine phosphokinase levels, and nasopharyngitis. Serious adverse events occurred in 1.6% of people taking 15 mg, 2.3% taking 30 mg, and 0.4% receiving placebo.

However, upadacitinib is not simply a hair-loss medicine. It is an immunomodulating drug with established uses in inflammatory conditions, and treatment decisions should be made with a healthcare professional.

The findings, published in JAMA Dermatology, suggest the drug could become another option for adults and adolescents with severe alopecia areata. Upadacitinib was approved for this use in the European Union in July 2026, while its US application remained under review.

Longer-term research will be important to determine how durable the hair regrowth is and to further assess the medicine's risks and benefits. The trials were funded by AbbVie, which manufactures upadacitinib and participated in the research and analysis.

For people living with severe hair loss, however, the results offer a potentially significant development: in some patients, controlling the immune response may help restore much of the hair that alopecia areata has taken away.

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