Researchers tested whether omega-3 fish oil supplements could help people with multiple sclerosis (MS) feel less tired, move more easily, and reduce inflammation in their bodies. Over 12 weeks, 68 MS patients either took fish oil pills or fake pills. While both groups showed some improvement in brain health markers, the fish oil didn’t work better than the placebo. Interestingly, women’s bodies responded differently to the supplements than men’s did. The study suggests that while fish oil is healthy, it may not be a special treatment for MS symptoms.

The Quick Take

  • What they studied: Whether taking omega-3 fish oil supplements for 12 weeks could help people with MS by reducing tiredness, boosting activity levels, and lowering inflammation in the body
  • Who participated: 68 people diagnosed with multiple sclerosis were split into two groups—one took fish oil pills (1000 mg twice daily) and the other took fake pills that looked identical
  • Key finding: Fish oil supplements didn’t work better than placebo pills. Both groups improved slightly in brain health markers, but the improvement was the same in both groups. Women’s bodies showed a different inflammation response than men’s, which was unexpected
  • What it means for you: If you have MS, taking fish oil supplements probably won’t reduce your fatigue or help you exercise more, based on this study. However, this is just one study, and fish oil has other health benefits, so talk to your doctor before stopping any supplements

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of medical research. Researchers randomly divided 68 MS patients into two equal groups. One group received omega-3 fish oil capsules (1000 mg taken twice daily), while the other group received identical-looking placebo capsules containing paraffin oil. Neither the patients nor the researchers knew who was getting the real fish oil—this is called “double-blind” and helps prevent bias.

The study lasted 12 weeks. Before and after the treatment period, researchers measured specific blood markers (BDNF and hs-CRP) that relate to brain health and inflammation. They also asked patients about their tiredness levels, how much they exercised, and their diet.

This design is strong because it controls for the placebo effect—the tendency for people to feel better just because they’re receiving treatment. By comparing the fish oil group to an identical-looking fake pill group, researchers can see if the fish oil itself made a difference.

The randomized controlled trial design is important because MS is a complex disease where many factors affect how people feel day-to-day. Without a placebo comparison, it would be impossible to know if improvements came from the fish oil or from other factors like better sleep, less stress, or natural disease fluctuations. The double-blind aspect prevents both patients and doctors from unconsciously influencing results based on their expectations.

This study has several strengths: it used a proper control group, was double-blind, and measured objective blood markers in addition to patient-reported symptoms. However, 12 weeks is a relatively short time period, and 68 participants is a moderate sample size. The study didn’t report dropout rates or side effects, which would have been helpful. The journal (Food Science & Nutrition) is peer-reviewed but has a lower impact factor than some medical journals, meaning the findings should be considered preliminary rather than definitive.

What the Results Show

The main finding was that omega-3 fish oil supplementation did not significantly improve any of the measured outcomes. When researchers looked at BDNF (a protein important for brain health), both the fish oil group and the placebo group showed increases from the beginning to the end of the study. However, the increase was essentially the same in both groups, meaning the fish oil didn’t provide extra benefit.

Similarly, for hs-CRP (a marker of inflammation in the body), both groups showed minimal changes, and again, there was no significant difference between the fish oil group and the placebo group. The researchers used advanced statistical methods to account for starting differences between groups, and the results remained the same—fish oil made no significant difference.

For the practical outcomes that matter most to MS patients, fish oil also didn’t help. Fatigue levels didn’t improve more in the fish oil group compared to placebo, and physical activity levels remained similar in both groups. Patients in both groups reported roughly the same amount of exercise and tiredness before and after the 12-week period.

One interesting secondary finding emerged: women and men responded differently to the treatment. Women in the fish oil group showed a 1.5-fold greater reduction in inflammation markers (hs-CRP) compared to men. This suggests that fish oil might have different effects depending on biological sex, though this finding needs confirmation in larger studies. This difference was statistically significant (p = 0.005), meaning it’s unlikely to be due to chance alone.

Previous research has suggested that omega-3 fatty acids have anti-inflammatory and brain-protective properties in general. However, this study adds to growing evidence that supplements showing promise in laboratory or animal studies don’t always translate to real benefits in patients with complex diseases like MS. Some earlier small studies suggested fish oil might help MS symptoms, but this larger, well-designed trial found no benefit, suggesting those earlier results may have been due to placebo effect or study limitations.

Several limitations should be considered when interpreting these results. First, 12 weeks may not be long enough to see changes in MS—the disease progresses slowly, and longer studies might show different results. Second, the study included only 68 people, which is a moderate sample size; larger studies might detect small effects that this study missed. Third, the researchers didn’t report how many people dropped out or experienced side effects, which would provide important context. Fourth, the study measured blood markers and patient-reported symptoms but didn’t use advanced imaging to look at actual brain changes. Finally, MS is highly variable between individuals, so some people might benefit while others don’t—this study looked at average effects across the group.

The Bottom Line

Based on this study alone, omega-3 fish oil supplements are not recommended as a treatment for MS fatigue or to improve physical activity (confidence level: moderate). However, this is one study, and fish oil has other documented health benefits for heart and brain health in the general population. If you have MS, continue following your neurologist’s prescribed treatments. You can eat fish naturally rich in omega-3s (like salmon) as part of a healthy diet, but don’t expect it to specifically treat MS symptoms. Always discuss supplements with your doctor before starting or stopping them.

This finding is most relevant to people with MS who are considering fish oil supplements specifically to reduce fatigue or increase activity. It’s also important for healthcare providers treating MS patients. However, this doesn’t mean fish oil is bad—it just means it’s not a proven MS treatment. People without MS who take fish oil for general health can continue doing so based on other research. Pregnant women, people on blood thinners, and those with fish allergies should always consult their doctor about supplements regardless of this study.

If you were considering trying fish oil for MS symptoms, this study suggests you wouldn’t notice improvements within 12 weeks. However, other MS treatments often take weeks to months to show effects, so individual responses vary. Don’t expect dramatic changes in fatigue or activity levels from fish oil supplements based on current evidence.

Want to Apply This Research?

  • Track daily fatigue levels (1-10 scale) and minutes of physical activity weekly. If using an app, log these metrics every evening to identify patterns over 4-week periods rather than expecting quick changes
  • Instead of relying on fish oil supplements for MS symptom management, focus on proven strategies: maintain consistent sleep schedules, track activity to gradually increase movement, and monitor fatigue patterns to identify triggers. Use the app to log these behaviors and share data with your healthcare team
  • Create a 12-week baseline of your current fatigue and activity levels before trying any new supplement. Then, if you choose to take fish oil for other health reasons, continue tracking these MS-specific metrics to see if you personally notice any changes. Share your personal data with your neurologist to inform treatment decisions

This study suggests omega-3 fish oil supplements don’t significantly improve MS symptoms like fatigue or physical activity levels. However, this is one research study and should not replace medical advice from your neurologist or healthcare provider. Multiple sclerosis is a serious condition requiring professional medical management. Do not start, stop, or change any treatments or supplements without consulting your doctor first. If you’re considering fish oil or any supplement, discuss it with your healthcare team, especially if you take blood thinners or have other medical conditions. This information is for educational purposes only and is not medical advice.