Dimethyl fumarate: what it does, uses and safety

Dimethyl fumarate (DMF) is an oral medication used mainly to treat relapsing forms of multiple sclerosis and some cases of psoriasis. You may know it under brand names like Tecfidera (MS) or Skilarence (psoriasis). Doctors prescribe it because it can lower immune activity that drives inflammation in these conditions.

How do you take it? DMF comes as delayed‑release capsules, commonly 120 mg and 240 mg. For multiple sclerosis, treatment often starts with a lower dose for the first week or two and then increases—your clinician will give exact instructions. Take capsules whole with food to cut down on flushing and stomach upset. Don’t crush or chew the pill.

How dimethyl fumarate works

DMF activates cellular pathways that help protect cells from oxidative stress, mainly the Nrf2 pathway, and it reduces overactive immune responses. That’s a simple way to say it calms the immune system while boosting some protective processes. The result can be fewer relapses in MS and reduced skin inflammation in psoriasis for some people.

Side effects and monitoring

Common side effects are flushing and gastrointestinal issues—nausea, diarrhea, stomach pain. Flushing tends to be worse at the start and may ease over weeks. Serious but less common problems include low white blood cell counts (lymphopenia) and liver enzyme elevations. Because of this, doctors check blood counts and liver tests before starting DMF and at regular intervals afterward.

If you develop frequent infections, unexplained bruising, jaundice, or severe persistent diarrhea, contact your provider. Some patients discuss taking aspirin to reduce flushing, but don’t do that without medical advice. Pregnant or breastfeeding people should speak to their clinician—DMF is typically avoided unless benefits outweigh risks.

What about vaccines and other medicines? Live vaccines may be discouraged while immune function is lowered. Tell your doctor about all medications, herbal products, and supplements you take. Combining DMF with other strong immunosuppressants increases infection risk and usually requires close monitoring.

Want practical tips? Always follow the exact dosing plan. Take the pill with a meal that has some fat to reduce stomach upset. Keep scheduled blood work—early detection of low lymphocytes or liver issues is key. Store capsules at room temperature away from moisture and keep them out of reach of children.

Thinking of buying DMF online? Only use licensed pharmacies that require a prescription. Check pharmacy reviews, verify contact info, and avoid sites offering prescription meds without a prescription. When in doubt, ask your healthcare team for a trusted source.

Quick checklist before starting DMF: get baseline blood counts and liver tests, confirm pregnancy status, update vaccines (live vaccines may need timing), list all current medicines and supplements, discuss infection history, and agree on a follow‑up schedule. Having a clear plan helps catch problems early and lets you stay on treatment safely. Keep your prescriber updated regularly.

Questions about DMF and your situation are best handled by your neurologist or dermatologist. They’ll balance benefits and risks and set up the right monitoring plan for you.