JAK Inhibitors For Alopecia: Efficacy & Safety
Reviewed by Katelyn Hagerty, FNP
Written by Our Editorial Team
The first JAK inhibitor for alopecia has been approved by the FDA, and it looks like an effective option for treating certain types of hair loss, such as alopecia areata.
However, these medications aren’t for everyone, and there are a few things you should know if you’ve read media headlines about JAK inhibitors and have questions about how they might fit into your hair loss prevention routine.
We’ve also explained JAK inhibitors for hair loss, including how these new medications work and why they might be worth considering if you have hair loss from moderate to severe alopecia areata.
The Basics of Hair Loss
There are several types of hair loss that can occur in adults. Of these, male pattern baldness, or androgenetic alopecia, is by far the most common, with up to 50 percent of men affected by the age of 50.
One less common type of hair loss is alopecia areata — a form of hair loss that’s caused by your immune system attacking your hair follicles. This type of hair loss can lead to small, round areas of hair loss — referred to as patches — developing on your scalp, face and body.
If you have alopecia areata, you may have heard of medications called Janus Kinase inhibitors (JAK inhibitors). These medications are used to treat inflammatory and autoimmune conditions, such as psoriatic arthritis.
Over the last few years, researchers have studied JAK inhibitors as a treatment for alopecia areata, and some medications have displayed promising results in clinical trials.
More recently, a JAK inhibitor called baricitinib (sold as Olumiant®) was approved by the Food and Drug Administration (FDA) to treat hair loss caused by alopecia areata.
What is Alopecia Areata?
Before we get into the specifics of JAK inhibitors, let’s briefly go over what alopecia areata is, as well as how it differs from the male pattern baldness most of us think of when we hear someone mention hair loss.
Alopecia areata is an autoimmune disease. It occurs when your immune system targets, attacks and damages your hair follicles — the tiny, tunnel-like structures inside your skin from which hair grows.
When your immune system targets your hair follicles, excessive inflammation can cause hair to suddenly shed.
Unlike male pattern baldness, which typically involves a receding hairline or bald patch and can be measured using the Norwood Scale, alopecia areata generally causes your hair to fall out in small patches about the size of a quarter.
Alopecia areata can vary in severity. For some people, it involves small patches of hair loss that are limited to the scalp. For others, it can progress to complete loss of facial and body hairs — a disease that’s referred to as alopecia universalis.
Our guide to alopecia areata goes into greater detail about alopecia areata, as well as the ways in which it differs from other types of hair loss.
Alopecia Areata and Conventional Hair Loss Treatments
Most of the time, hair loss in men can be treated using hair regrowth medications like finasteride and minoxidil.
Finasteride works by reducing the production of dihydrotestosterone (DHT), a hormone that can cause your hair follicles to miniaturize and shed. As your DHT levels decrease, your hair loss will slow, or even stop — and many men with signs of male pattern baldness can experience regrowth of hair.
But because alopecia areata isn’t triggered by DHT, medications like finasteride aren’t effective at stopping this form of hair loss.
Minoxidil works by improving blood flow to your scalp and moving your hair follicles into a state of active growth. Used on a frequent basis, it can also produce scalp hair regrowth in men with a receding hairline, bald spot or central scalp hair loss.
Minoxidil does have some effects for the treatment of alopecia areata. For example, in one clinical study, experts found that it produced noticeable regrowth of hair in patients with alopecia areata.
However, it’s currently recommended that minoxidil should be used in conjunction with other treatments for alopecia areata.
Put simply, conventional hair loss treatments — the types you might use if you notice a receding hairline or mild thinning — work well for male pattern baldness, but simply aren’t the best treatments for alopecia areata.
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How JAK Inhibitors Work for Alopecia Areata
Enter Janus Kinase inhibitors, or JAK inhibitors. These medications work through a complicated process that reduces your immune system’s ability to target certain areas of your body and cause autoimmune disease symptoms.
There are numerous JAK inhibitors on the market, some of which are used to treat patients with rheumatoid arthritis. These include Tofacitinib (sold under the brand name Xeljanz®), baricitinib (Olumiant) and upadacitinib (Rinvoq®).
Recently, the medication baricitinib, or Olumiant, was approved by the FDA for the treatment of adults with severe alopecia areata. The medication is the first of its type that’s approved to treat this form of hair loss not just on the scalp, but throughout the entire body.
Like other medications that receive FDA approval, baricitinib went through a complex series of clinical studies and safety assessments to determine not just that it’s effective, but also that it’s safe for people affected by alopecia areata to use on an ongoing basis.
In a series of randomized, placebo-controlled studies, a team of researchers found that people with alopecia areata experienced improvements in hair regrowth with baricitinib compared to a non-therapeutic placebo.
They also found that 4mg of baricitinib — the highest dose used in the studies — produced more of an improvement in human hair follicle regrowth than the lower 2mg dose.
In an interview with Yale News in 2022, Dr. Brett King, an associate professor of dermatology at Yale Medical School who was involved in the trials, stated that prior to FDA approval, access to JAK inhibitors for alopecia areata had been limited for patients.
The FDA’s recent approval of these medications is likely to dramatically expand access for the millions of Americans who live with alopecia areata, as well as give healthcare providers an extra degree of confidence when using this type of medication as a treatment approach.
Although baricitinib is currently the only JAK inhibitor that’s approved by the FDA as a treatment for hair loss, other medications in this class have also been studied.
For example, in a systematic review and meta-analysis published in the journal Frontiers in Pharmacology in 2022, researchers assessed the effectiveness of several selective inhibitors of JAK enzymes as hair loss treatments.
Using systems such as the Severity of Alopecia Tool (SALT), they found that JAK inhibitors had a good response rate. And though side effects were typically uncommon, mild and manageable, they did note that reports of adverse events varied across the studies they reviewed.
They concluded that JAK inhibitors are “efficacious and generally well-tolerated” as options for treating alopecia areata when used orally.
Are JAK Inhibitors Safe When Used for Hair Loss?
In order to gain FDA approval, medications don’t just need to demonstrate efficacy — they also need to show a good safety profile.
Like other medications, JAK inhibitors may cause side effects. According to the FDA, the most frequently reported side effects of baricitinib (Olumiant) include:
Skin issues, such as acne
Upper respiratory tract infections
Increased creatinine phosphokinase levels
Lower respiratory tract infections
Elevated liver enzyme levels
Urinary tract infections (UTIs)
Inflamed hair follicles (folliculitis)
Anemia (low red blood cells)
Low white blood cell count
High cholesterol levels
Genital yeast infections
Shingles (herpes zoster)
Baricitinib (Olumiant) should also not be used with some other medications, including other JAK inhibitors, biologic immunomodulators or other medications that suppress the immune system.
It’s also important to note that JAK inhibitors have several black box warnings, the strongest type of warning from the FDA.
If you have alopecia areata, your healthcare provider will discuss potential side effects, drug interactions and long-term safety with you before prescribing any type of JAK inhibitor, to make sure you can use this type of medication safely. Together, you and your doctor can weigh the potential risks and benefits of this medication for your particular situation.
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The Bottom Line on JAK Inhibitors for Hair Loss
If you’re affected by alopecia areata, using a JAK inhibitor such as baricitinib (sold as Olumiant) may help you to avoid developing patchy hair loss and regrow hair that you’ve lost as a result of your immune system attacking your hair follicles.
JAK inhibitors are fairly new medications for hair loss, and you may need to talk to a healthcare provider that specializes in the treatment of patients with alopecia areata in order to access this type of medication.
You can do this by talking to your primary care provider and asking for a dermatology referral, or by scheduling an appointment with a healthcare provider in your area who specializes in treating autoimmune hair loss.
However, there are a few things that you should keep in if mind if you’re considering this type of medication for hair loss:
Not everyone experiences improvements. Research suggests that up to nearly two in every five people experience significant hair regrowth with Olumiant. In other words, it works in some cases, but not for everyone.
JAK inhibitors aren’t proven to treat male pattern baldness. This type of medication is only approved for severe alopecia areata, not the male pattern hair loss that can cause a receding hairline.
We offer these medications as part of our range of hair loss treatments for men, with finasteride available following a consultation with a healthcare provider who will determine if a prescription is appropriate.
Interested in learning more before you get started? Our guide to the best treatments for thinning hair covers all of the essentials about eliminating shedding and maintaining your hair as you get older, from medications to healthy habits and more.