Tecfidera (dimethyl fumarate) for multiple sclerosis

Last updated June 12, 2025, by Lindsey Shapiro,PhD
Fact-checked by Ines Martins, PhD

What is Tecfidera for MS?

Tecfidera (dimethyl fumarate) is an approved oral therapy indicated for adults with relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), and active secondary progressive MS (SPMS).

Taken twice daily as capsules, Tecfidera has been shown in clinical trials to reduce relapse rates, slow the development of brain lesions, and delay disability progression.

The disease-modifying therapy contains an inactive molecule called dimethyl fumarate that is converted to its active form, monomethyl fumarate (MMF), once inside the body. It’s not entirely clear how MMF works to reduce MS disease activity, but it’s generally believed to change the activity of immune cells in ways that reduce MS-driving inflammation. It also has antioxidant properties that could protect nerve cells against damage.

The brand name medication is marketed by Biogen, but there are several generic versions available in the U.S. Biogen also markets a newer MS therapy called Vumerity (diroximel fumarate), which delivers a similar amount of MMF as Tecfidera, but has been shown to have fewer gastrointestinal side effects.

Therapy snapshot

Who can take Tecfidera?

Tecfidera is approved in the U.S. for adults with CIS, RRMS, and active SPMS.

It is contraindicated for people with a history of hypersensitivity reactions — a type of exaggerated immune response that includes allergic reactions — to dimethyl fumarate or any other ingredient in the medication.

The therapy is also approved for treating MS in dozens of other countries=, but indications may vary. For example, in the European Union, Tecfidera is solely approved for RRMS, but can be used in patients as young as 13.

How is Tecfidera administered?

Tecfidera comes in delayed-release oral capsules, which must be swallowed whole twice per day, with or without food.

The recommended maintenance dose is 480 mg, or 240 mg twice daily, but patients usually start with 120 mg twice daily for the first week.

If patients fail to tolerate the maintenance dose, they may temporarily decrease their daily dosage at a doctor’s discretion. A doctor may also recommend taking Tecfidera with food or aspirin if a person experiences flushing, or reddening of the skin, a common side effect of the medication.

Tecfidera in clinical trials

Tecfidera’s approval in the U.S. was supported mainly by data from two large Phase 3 clinical trials, which collectively involved more than 2,400 adults with RRMS. In both studies, participants were randomly assigned to receive Tecfidera or a control treatment (placebo or an approved MS therapy) for about two years.

• The DEFINE trial (NCT00420212) showed that Tecfidera significantly reduced relapse rates compared with a placebo and decreased the number of new and enlarging lesions, as well as the number of lesions with active inflammation, visible on MRI scans. Significantly fewer people given Tecfidera experienced a confirmed worsening of disability compared with those on a placebo.
• In the CONFIRM trial (NCT00451451), Tecfidera also significantly reduced relapse rates compared with a placebo, and the reduction was generally greater than that observed with the approved injectable therapy glatiramer acetate (sold as Copaxone, among others). It also reduced brain lesions compared to the placebo, although no differences were observed with disability worsening.
• The ENDORSE Phase 3 extension study (NCT00835770) involving DEFINE and CONFIRM participants generally showed that relapse rates remained low over up to 13 years of follow-up, and most hadn’t experienced confirmed disability progression.

Other Phase 2 and Phase 3 studies have demonstrated Tecfidera’s possible benefits in children with RRMS, ages 10-17. Data from the Phase 3 CONNECT trial (NCT02283853), which showed that Tecfidera outperformed the MS therapy Avonex (interferon beta-1a) at preventing brain lesion development and reducing relapse rates, supporting its approval in the EU for children, ages 13 and older.

Tecfidera side effects

The most common side effects of Tecfidera include:

• flushing
• abdominal pain
• diarrhea
• nausea.

These symptoms usually ease or resolve over time, but they may be severe in some patients. If they continue to be intolerable or lead to more serious complications, Tecfidera may have to be discontinued.

Other less common, but serious side effects also may occur with Tecfidera. They include:

• anaphylaxis, a severe allergic reaction that may cause swelling of the tongue and throat, and be life-threatening
• serious infections, including progressive multifocal leukoencephalopathy, a potentially fatal brain infection
• low immune cell counts, which may be prolonged and severe
• liver injury
• serious gastrointestinal reactions, some of which may lead to death.

Signs of any of these problems could mean Tecfidera has to be paused or stopped permanently. A doctor will keep an eye out for them throughout treatment.

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