Baricitinib: How did a drug for arthritis end up helping people regrow hair from alopecia areata?

Baricitinib was originally approved as a treatment for rheumatoid arthritis, an autoimmune disease that causes inflammation and joint damage. Its medical use seemed confined to inflammatory disorders. However, in 2022, the U.S. Food and Drug Administration (FDA) approved it as the first systemic treatment for severe alopecia areata. This unexpected turn raises a natural question: How did a joint medication end up helping people with alopecia areata regrow their hair?

Alopecia areata is an autoimmune disease where the immune system, which normally defends the body against viruses and bacteria, mistakenly attacks hair follicles—the structures from which hair grows. This disrupts the natural growth cycle and causes sudden hair loss in round patches on the scalp, eyebrows, or eyelashes. In some cases, hair loss remains localized. But in its severe form, the disease progresses and causes the loss of 50% or more of the scalp hair or even all body hair. This severe version can profoundly affect not only personal image but also emotional health.

For years, available treatments only addressed symptoms or had limited long-term effectiveness. Corticosteroids or immunosuppressants were used, which offered temporary improvement but came with significant side effects. Researchers looked for treatments that target the immune cause more directly. Baricitinib was one of them. Baricitinib is a strong immunosuppressant. Its FDA label carries a boxed warning for serious infections, death from any cause, cancer, major cardiovascular events (such as heart attack and stroke) and blood clots. The label says to test for tuberculosis before starting, to avoid live vaccines, and that the drug may cause harm to an unborn baby; it also advises not to breastfeed during treatment. Regrowth is usually lost when it is stopped.

How is it different from minoxidil, the most well-known hair loss treatment?

Minoxidil is a topical treatment applied directly to the scalp. It’s approved for genetic hair loss (androgenetic alopecia) and is thought to act partly on blood flow and the growth phase of hair follicles, though its exact mechanism is not fully known. This stimulates hair growth in people with a genetic predisposition, but it doesn’t treat the underlying cause when hair loss is due to an immune system attack, as in alopecia areata. Baricitinib, on the other hand, works from the inside and targets the immune cause of the disease. It’s an oral pill that changes how the immune system behaves. Instead of stimulating hair growth from the outside like minoxidil, baricitinib dampens the immune signalling behind the hair loss. This makes it especially relevant for people with severe alopecia areata, where minoxidil alone usually yields poor results.

An overactive cellular pathway: explaining the JAK-STAT system in plain language

Our body works through a large network of signals. When something goes wrong, those signals can become excessive or faulty. In alopecia areata, certain immune cells send harmful messages that lead the body to attack its own hair follicles. Baricitinib blocks one of those communication channels, known as the JAK-STAT pathway. If we think of this pathway as a game of telephone between cells, baricitinib is like cutting the call so the "attack" message doesn’t go through. As a result, in people who respond, the attack on hair follicles is reduced and they can start producing hair again. This doesn’t happen overnight, but over time the scalp may begin to show signs of recovery in those who respond to the treatment.

From lab to scalp: what do the studies say?

The use of baricitinib for alopecia areata rests on clinical trials. A key study was published in 2022 in the New England Journal of Medicine and funded by Eli Lilly, the manufacturer of baricitinib. This research included two randomized, double-blind clinical trials: BRAVE-AA1 and BRAVE-AA2. A total of 1,200 adults with severe alopecia areata (with at least 50% hair loss) participated. Both trials lasted 36 weeks. Researchers compared baricitinib at 2 mg and 4 mg daily doses to a placebo (a pill with no active ingredient). The results were evaluated using the Severity of Alopecia Tool (SALT), a validated scale that measures the percentage of hair loss.

At week 36 in BRAVE-AA1, about 39% of those taking 4 mg of baricitinib daily had 80% or more scalp coverage, compared with about 6% in the placebo group (about 36% vs 3% in BRAVE-AA2). In the trials, acne, raised creatine kinase (a muscle enzyme) and raised LDL and HDL cholesterol were more common with baricitinib than with placebo. Later data from the same trials showed that most responders who stayed on treatment kept their regrowth through 104 weeks (Senna et al., 2024), but about 80% of the 40 responders switched to placebo lost their benefit by week 152 (King et al., 2024). Based on these results, in June 2022, the FDA approved baricitinib for adults with severe alopecia areata. It was the first time an oral systemic medication (one that affects the whole body) was authorized for this disease. This approval marks a milestone, recognizing alopecia areata as a serious condition that deserves specific therapeutic options—not just cosmetic or palliative solutions.

While about a third of trial patients responded well, it’s important to understand that baricitinib is not a permanent cure. It works while it’s being taken.

If the treatment is stopped, hair loss can return. Additionally, not everyone responds the same: some people experience partial or delayed regrowth, and others don’t respond at all. Researchers are currently studying what factors predict a good response, including the duration of alopecia, level of inflammation, and genetic markers. Baricitinib’s use has opened a new line of research into autoimmune diseases affecting skin and hair. Studies are underway to assess its effectiveness in younger populations, in combination with other treatments like laser therapy or minoxidil, and its long-term use. Other JAK inhibitors are also being tested for different skin conditions, which could expand the range of treatment options available.

Baricitinib on the market: how is it sold and under what names?

Baricitinib is sold under the brand name Olumiant®, produced by pharmaceutical company Eli Lilly. Although it has been approved for rheumatoid arthritis since 2018, its specific indication for alopecia areata was added in 2022. The drug is available by prescription only and isn’t approved in all countries for the same indications. In some places, it’s still used "off-label" (for a different use than officially approved). Anyone considering this treatment should always do so under the guidance of a dermatologist or specialist in autoimmune diseases.

References

King B, Ohyama M, Kwon O, et al. Two Phase 3 Trials of Baricitinib for Alopecia Areata. N Engl J Med. 2022;386(18):1687-1699. https://pubmed.ncbi.nlm.nih.gov/35334197/

King B, Ko J, Kwon O, et al. Baricitinib Withdrawal and Retreatment in Patients With Severe Alopecia Areata: The BRAVE-AA1 Randomized Clinical Trial. JAMA Dermatol. 2024;160(10):1075-1081. https://pubmed.ncbi.nlm.nih.gov/39141364/

Senna M, Mostaghimi A, Ohyama M, et al. Long-term efficacy and safety of baricitinib in patients with severe alopecia areata: 104-week results from BRAVE-AA1 and BRAVE-AA2. J Eur Acad Dermatol Venereol. 2024;38(3):583-593. https://pubmed.ncbi.nlm.nih.gov/38391212/

U.S. Food and Drug Administration. (2022, June 13). FDA Approves First Systemic Treatment for Alopecia Areata. https://www.fda.gov/news-events/press-announcements/fda-approves-first-systemic-treatment-alopecia-areata

U.S. National Library of Medicine. OLUMIANT (baricitinib) tablets, prescribing information. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=866e9f35-9035-4581-a4b1-75a621ab55cf