Baricitinib and JAK inhibitors: the new treatment for alopecia areata

For decades, alopecia areata (those patches of sudden hair loss that sometimes progress until the scalp is left bare) had no systemic drug approved specifically for it. That changed in 2022. Baricitinib, a tablet already in use for other conditions, became the first systemic treatment approved for severe alopecia areata. Here we explain what it is, what the trials say and, above all, what they do not say.

The situation in Spain: authorised in adults and adolescents, funded in adults

Baricitinib (brand name Olumiant, from Eli Lilly / Incyte) is authorised in Spain for severe alopecia areata in adult patients and in adolescents aged 12 and over. The indication appears in the CIMA/AEMPS summary of product characteristics for the 2 mg and 4 mg tablets, and funding by the Spanish National Health System for this indication in adults was approved in 2023, together with its corresponding Therapeutic Positioning Report (IPT-185).

The recommended dose in alopecia according to the Spanish summary of product characteristics is 4 mg a day, reduced to 2 mg a day in patients at higher risk of venous thromboembolism, cardiovascular risk or malignancy, those over 65 or those with chronic infections. One caveat is worth flagging here: in the US label (FDA) the criterion is different, treatment starts at 2 mg a day and is increased to 4 mg if the response is insufficient. They are not the same scheme, so there is no point extrapolating the dose from one country to another.

As for under-18s, the current Spanish summary of product characteristics is now explicit: the indication includes adolescents aged 12 and over with severe alopecia areata, with a recommended dose of 4 mg a day in those weighing 30 kg or more. That extension came after a European procedure (we set this out further down).

What it is and how it works

Baricitinib is a selective, reversible oral inhibitor of the Janus kinases JAK1 and JAK2. In alopecia areata, the immune system mistakenly attacks the hair follicle through signals from certain cytokines (among them those of the interferon gamma and IL-15 pathways). Baricitinib blocks that signalling, which curbs the autoimmune attack and allows hair to grow back in a proportion of patients.

One technical point that matters: baricitinib acts on JAK1 and JAK2. It belongs to the same family as other JAK inhibitors used in alopecia, such as ritlecitinib (which acts on JAK3/TEC), but they are not mechanistically interchangeable. And the baricitinib trials were run against placebo, not head to head against other JAK inhibitors, so it cannot be claimed that one is superior to another.

What the trials found

The main evidence comes from two phase 3 randomised, double-blind, placebo-controlled trials published in the New England Journal of Medicine in 2022: BRAVE-AA1 (654 participants) and BRAVE-AA2 (546 participants), a programme of around 1,200 adult patients with severe alopecia areata. Participants were allocated in a 3:2:2 ratio to receive baricitinib 4 mg, baricitinib 2 mg or placebo.

The primary endpoint was the proportion of patients reaching a SALT score of 20 or less at week 36. The SALT score measures the percentage of scalp without hair, so a SALT of 20 or less means having at least 80% of the scalp covered. These were the results:

• BRAVE-AA1: 38.8% with 4 mg, 22.8% with 2 mg and 6.2% with placebo.
• BRAVE-AA2: 35.9% with 4 mg, 19.4% with 2 mg and 3.3% with placebo.
• The difference for the 4 mg dose versus placebo at week 36 was 32.6 percentage points in both trials (95% CI 25.6-39.5 in BRAVE-AA1; 25.6-39.6 in BRAVE-AA2).

Some honesty about the figures is needed here. That 38.8% or 35.9% is not a complete response or full regrowth: it is the proportion of patients who ended up with at least 80% of the scalp covered at 36 weeks. Put another way, with the 4 mg dose a little over a third of patients reached that threshold, and the rest did not. Nor is it correct to talk about a cure: the trials measured hair regrowth at 36 weeks, not a cure, and the condition can relapse when treatment is stopped.

Side effects and safety warnings

Baricitinib belongs to the JAK inhibitor class, and this class carries significant safety warnings from the EMA and the FDA. They relate to the risk of serious infections, venous thromboembolism, major adverse cardiovascular events and malignancies. That is precisely why the Spanish summary of product characteristics reserves the 2 mg dose (rather than 4 mg) for patients at higher risk of these problems: those over 65, those with cardiovascular or thromboembolic risk, those with a history of malignancy or those with chronic infections.

We do not give exact frequencies here for specific adverse reactions (such as acne, infections or laboratory abnormalities) because the tables in the summary of product characteristics combine data from different conditions (arthritis, atopic dermatitis and alopecia), and quoting a figure without verifying the exact source would be misleading. The authoritative source for those numbers is the full CIMA/AEMPS summary of product characteristics.

What about adolescents? Now included in the summary of product characteristics

On 26 February 2026, the EMA's Committee for Medicinal Products for Human Use (CHMP) issued a positive opinion on extending the use of baricitinib to adolescents aged 12 to under 18 with severe alopecia areata, on the basis of the paediatric BRAVE-AA-PEDS trial (in which 42% of those treated with 4 mg achieved at least 80% scalp hair coverage at week 36). That extension is now reflected in the current Spanish summary of product characteristics, which indicates baricitinib for severe alopecia areata in adults and in adolescents aged 12 and over. But it pays to be precise: the funding by the Spanish National Health System approved in 2023 referred to adults.

What is available in Spain today

There is now a first systemic drug authorised in Spain for severe alopecia areata in adults and in adolescents aged 12 and over, and publicly funded in adults since 2023. It is not a cure, it carries the safety warnings of its class, and the decision to prescribe it rests with a specialist, usually in a hospital setting.

And if what you have is not severe alopecia areata but ordinary hair loss, that can also be addressed medically today. In Spain that route is medical treatment for hair loss with a prior assessment, a prescription where appropriate from a registered doctor and ongoing follow-up by the medical team. You can check in a few minutes whether you are eligible.