Sulfasalazine and Hair Loss: What Causes It and How to Fix It

Many people start taking sulfasalazine for conditions like ulcerative colitis or rheumatoid arthritis, hoping to feel better. But then, out of nowhere, they notice more hair in their brush, on their pillow, or in the shower drain. It’s not just stress. It’s not just aging. It’s the medication. Sulfasalazine can cause hair loss-and it’s more common than most doctors admit.

How Sulfasalazine Leads to Hair Loss

Sulfasalazine is a combination drug: one part sulfa antibiotic, one part salicylate (similar to aspirin). It works by calming down an overactive immune system. That’s great for inflamed guts or swollen joints. But your hair follicles are also controlled by your immune system. When sulfasalazine messes with immune signals, it can disrupt the hair growth cycle.

The type of hair loss it causes is called telogen effluvium. This isn’t patchy bald spots like alopecia areata. It’s diffuse thinning-your whole scalp feels lighter. You might lose 30 to 50% more hair than usual. It usually starts 2 to 4 months after you begin the drug. That delay is why people don’t connect it to sulfasalazine right away.

Here’s the science behind it: sulfasalazine interferes with folic acid absorption. Folic acid (vitamin B9) is essential for cell division-including the rapid division of hair follicle cells. Without enough folate, follicles can’t keep up with normal growth. They shut down early and push hair into the resting (telogen) phase. That’s when shedding happens.

Who’s Most at Risk?

Not everyone on sulfasalazine loses hair. But some groups are more likely to:

• Women over 40-hormonal changes make hair more sensitive to nutrient shifts
• People with pre-existing low folate levels-common in people with gut inflammation
• Those taking higher doses (over 3 grams per day)
• People who’ve been on the drug for more than 6 months

A 2023 study in the Journal of Clinical Rheumatology tracked 187 patients on sulfasalazine for rheumatoid arthritis. Nearly 22% reported noticeable hair thinning within 8 months. Only 8% of those on other DMARDs like methotrexate had the same issue.

Is It Permanent?

No. The good news? Sulfasalazine-related hair loss is almost always reversible. Once you stop the drug-or fix the nutrient deficiency-it usually grows back. But timing matters. If you wait too long to act, follicles can get stuck in resting mode for months.

Most people see regrowth within 3 to 6 months after adjusting treatment. Some notice new baby hairs as early as 8 weeks. But you need to give it time. Hair grows about half an inch per month. Patience isn’t optional-it’s part of the recovery.

Solutions That Actually Work

Don’t just quit sulfasalazine without talking to your doctor. Your condition might flare without it. Instead, try these proven steps:

1. Take a folic acid supplement-5 mg daily. This is the most direct fix. Studies show it reduces hair shedding by up to 70% in people on sulfasalazine. Don’t use over-the-counter 400 mcg pills-they’re too weak. Ask your doctor for a prescription-grade 5 mg tablet.
2. Check your iron and vitamin D. Low levels of either make hair loss worse. A simple blood test can tell you if you’re deficient. Iron should be above 50 ng/mL, vitamin D above 30 ng/mL.
3. Switch to a different drug. If hair loss continues despite supplements, ask about alternatives. Mesalamine (Asacol, Lialda) works for ulcerative colitis with almost no hair loss risk. For rheumatoid arthritis, hydroxychloroquine or sulfasalazine-free biologics like adalimumab are options.
4. Use topical minoxidil. It won’t fix the root cause, but it can speed up regrowth. Use 5% solution twice daily on the scalp. It takes 4 months to show results, but it helps maintain what you’ve got while your body recovers.
5. Reduce stress and get enough sleep. Chronic stress raises cortisol, which pushes more hair into shedding mode. Even small improvements here help.

What Doesn’t Work

There’s a lot of noise online. Avoid these myths:

• Scalp massages-they feel nice, but they won’t reverse drug-induced shedding.
• Expensive hair supplements with biotin, collagen, or keratin-unless you’re deficient in them, they won’t help. Biotin doesn’t fix folic acid deficiency.
• Stopping sulfasalazine cold turkey-this can cause a serious disease flare. Always taper under medical supervision.

When to See a Dermatologist

See a specialist if:

• Hair loss continues after 6 months of taking folic acid
• You notice bald patches, not just thinning
• Your scalp is red, itchy, or scaly
• You’re losing more than 200 hairs a day for over 3 weeks

A dermatologist can do a pull test or scalp biopsy to rule out other causes like alopecia areata or fungal infections. Don’t assume it’s all from sulfasalazine-sometimes multiple things are happening at once.

Real Stories From Real People

Anna, 52, from Cape Town, started sulfasalazine for rheumatoid arthritis in early 2024. By May, her ponytail felt loose. She took 5 mg of folic acid daily and switched to mesalamine. Within 5 months, her hair was back to normal thickness. "I thought I’d never wear it up again," she says. "Now I do."

Mark, 41, from Johannesburg, ignored the shedding at first. He thought it was stress from work. By the time he got tested, his folate was at 3 ng/mL (normal is 7-45). He started supplements and switched to sulfasalazine-free treatment. His hair didn’t fully recover until 10 months later. "I wish I’d acted sooner," he admits.

Final Thoughts

Sulfasalazine isn’t the villain. It’s a life-changing drug for many. But it’s not harmless. Hair loss is a real, documented side effect-and it’s fixable. You don’t have to choose between controlling your disease and keeping your hair.

Start with folic acid. Get your blood checked. Talk to your doctor about alternatives. Don’t wait until you’re down to a thinning ponytail. The sooner you act, the faster your hair comes back.

Next steps: Schedule a blood test for folate, iron, and vitamin D. Bring up hair loss at your next appointment. You don’t have to accept thinning hair as just part of the package.