Fish Oil for Hot Flashes: What Two Placebo-Controlled Trials Found
Menopause & HormonesArticleCompare the participants, preparation and symptom counts before interpreting a drop in hot flashes after starting capsules.
In this article
If you are considering fish oil for hot flashes, ask which symptom the supplement is meant to change and which trial supports that use. Bring the full product label, including the amounts of EPA and DHA, to the discussion.
The larger trial found similar improvement with placebo
The 2014 MsFLASH trial1 randomized 355 women aged 40–62, 177 to omega-3s and 178 to placebo. The healthy, sedentary perimenopausal or postmenopausal participants averaged 7.6 hot flashes or night sweats daily at baseline. A separate randomization assigned yoga, exercise or usual activity.1
The supplement supplied 1.8 grams of omega-3s daily for 12 weeks; the matching placebo contained olive oil. Average daily symptom frequency fell by 2.5 episodes with omega-3s and 2.7 with placebo. The between-group comparison was not statistically significant, P=0.28. Neither symptom bother nor the sleep and mood measures improved significantly compared with placebo. The trial received federal funding; Nordic Naturals donated capsules and placebo.1
A lower count after starting a supplement does not by itself establish that the supplement caused the change. In this trial, the placebo group also improved substantially.
Why the smaller positive trial needs context
An earlier trial published in 2009 randomized 120 women aged 40–55 who had moderate to severe psychological distress to an EPA-enriched preparation or placebo for eight weeks. The hot-flash analysis included only the 91 women who had hot flashes, 45 taking the active preparation and 46 placebo.2
They averaged 2.8 hot flashes daily at baseline. Frequency fell by 1.58 a day with the supplement and 0.50 with placebo, a significant difference. However, changes in hot-flash intensity and menopause-specific quality of life did not differ significantly between groups. The authors called for confirmation in a study designed for women with more troublesome hot flashes.2
These trials enrolled different populations and used different preparations. Their results do not identify an effective dose for the hot flashes of an individual reader. They also do not show that increasing a dose after an unhelpful trial will produce relief.12
Read the EPA and DHA amounts
The NIH3 Office of Dietary Supplements explains that 1,000 milligrams of fish oil might contain about 180 milligrams of EPA and 120 milligrams of DHA, although products vary widely. The total oil weight on the front of a bottle is therefore different from its EPA and DHA content. Check the serving size and amounts on the back.3
NIH3 lists usually mild adverse effects including unpleasant taste, bad breath, heartburn, nausea, gastrointestinal discomfort and diarrhea. It also advises discussing medicine interactions with a clinician. If you take warfarin or a similar anticoagulant, ask the prescriber or pharmacist whether monitoring is needed; the fact sheet notes that most research has not found a significant change in anticoagulant status in people taking warfarin at the doses studied.3
Those details help assess a product’s contents and risks. They do not establish that the product treats hot flashes.
Ask about options supported for hot flashes
The Menopause Society’s 2023 nonhormone therapy statement describes omega-3 evidence as mixed and inconclusive and does not recommend it for vasomotor symptoms. Its recommended nonhormone options include menopause-focused cognitive behavioral therapy, clinical hypnosis and several prescription treatments.4
Tell the clinician whether your priority is fewer daytime episodes, fewer night awakenings or less interference with work. Ask which options fit your history, what benefit to expect and when to review the choice. If omega-3 was prescribed for another condition, discuss that separate purpose before changing it.
My Body Changed. Now What? includes “Try It” in Chapter 5, “The Heat.” Its diary prompts record flash counts, waking from night sweats, symptom bother, the change being tried and its start date. Bring that record alongside the supplement label.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please don't ignore professional advice or delay getting care because of something you read here. If you think you may be having a medical emergency, call 911 or your local emergency number right away. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- Cohen and colleagues, Menopause, 2014Efficacy of omega-3 for vasomotor symptoms treatment: a randomized controlled trial (opens in a new tab)abcd
- Lucas and colleagues, Menopause, 2009Effects of ethyl-eicosapentaenoic acid omega-3 fatty acid supplementation on hot flashes and quality of life among middle-aged women: a double-blind, placebo-controlled, randomized clinical trial (opens in a new tab)abc
- National Institutes of Health, Office of Dietary SupplementsOmega-3 Fatty Acids: Health Professional Fact Sheet (opens in a new tab)abcd
- The North American Menopause Society, 2023The 2023 nonhormone therapy position statement of The North American Menopause Society (opens in a new tab)↩
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