Medically reviewed by Dr. Reina Punj, MBBS, PG Diploma in Endocrinology (University of South Wales), Lead Physician, Excelgenics Clinical Panel.
The main benefit of flaxseed oil is nutritional: it is the richest common food source of alpha-linolenic acid (ALA), an essential plant omega-3 fat, which makes it especially useful for vegetarians. Beyond that, the research on flaxseed oil benefits is modest and mixed: studies suggest a small effect on blood pressure, but flaxseed oil on its own has not been shown to lower cholesterol. Flaxseed oil capsules and pills deliver the same ALA in much smaller, measured amounts. Here is what the evidence says, how oil compares with ground seeds, and how to take it safely.
What is flaxseed oil?
Flaxseed oil (also called linseed or alsi oil) is pressed from the seeds of the flax plant. One tablespoon contains about 7.3 g of ALA, more than any other common food. Adults need an adequate intake of about 1.1 g of ALA a day for women and 1.6 g for men (US figures from the NIH Office of Dietary Supplements).
ALA is the only omega-3 fat that is strictly essential, because the body cannot make it. It is not the same as EPA and DHA, the omega-3s in fish oil. The body can convert some ALA into EPA and DHA, but the process is very limited, with reported rates of less than 15%. So flaxseed oil is a good source of ALA, but not a substitute for EPA and DHA. Our Vegan Omega-3 Supplements Guide explains the difference in detail.
Flaxseed oil benefits: what the research shows
Cholesterol
In Europe, ALA is authorised to be described as contributing to the maintenance of normal blood cholesterol levels, with the beneficial effect obtained from a daily intake of 2 g of ALA. This is a recognised role of the nutrient ALA at that intake.
Studies of flaxseed oil itself are less encouraging. A 2009 meta-analysis of 28 studies found that whole flaxseed was linked to small reductions in total and LDL cholesterol, but flaxseed oil showed no significant effect on either. A 2025 review that graded the human evidence for flaxseed oil supplements also concluded that it did not improve blood lipids.
Blood pressure
A 2016 meta-analysis of 15 trials (about 1,300 people) found that flaxseed supplements were linked to small reductions in blood pressure, of roughly 2–3 mmHg. When the authors looked at the form used, flaxseed powder lowered both the top (systolic) and bottom (diastolic) numbers, while flaxseed oil lowered only the diastolic number. The 2025 evidence-graded review also reported a blood pressure reduction with flaxseed oil, although in one comparison the effect was weaker than with whole flaxseed. These are small average effects found in research studies. They do not mean flaxseed oil can replace blood pressure treatment, and anyone with high blood pressure should follow their doctor's advice.
Heart health more broadly
A 2012 meta-analysis of 27 observational studies (about 251,000 people) found that people with higher dietary ALA intake had a moderately lower risk of cardiovascular disease. This shows an association, not cause and effect, and does not show that an ALA supplement reduces risk.
Other claimed benefits
Claims about flaxseed oil for weight loss, joints, skin, hair and hormones mostly rest on laboratory or animal work, or on very small trials. The NCCIH notes that flaxseed oil does not seem to help with weight loss. For the evidence on hair specifically, see flaxseed oil for hair: what the evidence really says.
Flaxseed oil vs ground flaxseed
| Flaxseed oil | Ground flaxseed | |
|---|---|---|
| ALA | Concentrated: about 7.3 g per tablespoon | Present, in smaller amounts |
| Fibre | None | Yes |
| Lignans | Not typically, unless ground seed is added | Yes: flaxseed is the richest dietary source |
| Cholesterol research | No significant effect in a 2009 meta-analysis | Small reductions in the same meta-analysis |
If your interest is the whole package of flaxseed, including fibre and lignans, ground flaxseed in food is the more complete option. Grinding the seeds helps the body absorb their lignans. If your aim is simply ALA in a convenient form, oil or capsules make sense.
Flaxseed oil capsules and pills: benefits vs bottled oil
The benefits of flaxseed oil pills come from the same ALA as bottled oil, but the amounts are very different. A tablespoon of oil gives about 7.3 g of ALA; a capsule containing 560 mg of flaxseed oil gives an estimated ~300 mg. Capsules are convenient, measured and tasteless, and avoid an open bottle of oil. Bottled oil gives far more ALA per serving and can be used cold in food, for example drizzled over salads, raita or dal after cooking.
Omegaco Flaxseed Oil Omega-3 Capsules provide 560 mg of cold-pressed flaxseed oil per capsule (an estimated ~300 mg ALA) in a plant-based vegetarian capsule, with no preservatives and no fish derivatives. It contains no EPA or DHA, and its ALA content is well below the 2 g a day linked to the cholesterol role described above, so that role does not apply to it. Most of your ALA should still come from food.
How to take and store flaxseed oil
- Capsules: follow the dose on the label and take them with a meal that contains some healthy fat.
- Bottled oil: use it cold, added to food after cooking, and follow the storage instructions on the bottle. ALA is a polyunsaturated fat, and the oil can go rancid; if it smells sharp, fishy or like paint, throw it away.
- Combine with food sources: ground flaxseed, chia seeds and walnuts all add ALA.
- Time of day: omega-3 capsules are usually taken with a meal. For questions about timing, see can we take omega-3 at night?
Flaxseed oil safety and side effects
- Digestive effects: higher doses can cause bloating, fullness or diarrhoea.
- Blood thinners: flaxseed oil might add to the effect of anticoagulant or antiplatelet medicines. Speak to your doctor before use if you take them.
- Pregnancy and breastfeeding: little is known about the safety of flaxseed oil supplements at these times, so avoid them unless your doctor advises it.
- Length of use: the NCCIH says oral flaxseed oil in limited amounts may be safe for up to 6 months; review longer-term use with your doctor.
- Medicines and conditions: if you take regular medicine or have a diagnosed condition, check with your doctor or pharmacist first.
For how flaxseed oil compares with fish oil, read flaxseed oil vs fish oil: can a plant-based omega compete?
Frequently asked questions
What are the benefits of flaxseed oil capsules?
Flaxseed oil capsules provide ALA, an essential omega-3 fat, in a convenient, measured form, which is useful if you rarely eat flaxseed, chia or walnuts. They do not provide EPA or DHA, fibre or lignans, and the research benefits linked to whole flaxseed do not automatically apply to them.
Are there flaxseed oil benefits for females?
There is no good evidence of benefits specific to women. Women have a lower ALA adequate intake (1.1 g a day) and, in small studies, young women converted more ALA to EPA and DHA than men, possibly because of oestrogen. Pregnant or breastfeeding women should avoid flaxseed oil supplements unless a doctor advises them, and should ask their doctor whether they need EPA and DHA.
Are there flaxseed oil benefits for males?
Again, there is no good evidence of male-specific benefits. Men have a higher ALA adequate intake (1.6 g a day) and, in small studies, converted less ALA to EPA and DHA than women.
Can I take flaxseed oil every day?
Yes, at the dose on the label, for most adults. The NCCIH suggests limited amounts may be safe for up to 6 months, so discuss longer use with your doctor, especially if you take blood thinners.
Is flaxseed oil as good as fish oil?
They are not interchangeable. Flaxseed oil provides ALA; fish oil provides EPA and DHA. Because conversion is limited, research on fish oil should not be applied to flaxseed oil.
References
- National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. ods.od.nih.gov
- Linus Pauling Institute, Oregon State University. Essential Fatty Acids. lpi.oregonstate.edu
- Linus Pauling Institute, Oregon State University. Lignans. lpi.oregonstate.edu
- Commission Regulation (EU) No 432/2012, list of permitted health claims (alpha-linolenic acid). eur-lex.europa.eu
- Pan A, Yu D, Demark-Wahnefried W, Franco OH, Lin X. Meta-analysis of the effects of flaxseed interventions on blood lipids. American Journal of Clinical Nutrition. 2009;90(2):288–297. doi:10.3945/ajcn.2009.27469
- Ursoniu S, Sahebkar A, Andrica F, et al. Effects of flaxseed supplements on blood pressure: a systematic review and meta-analysis of controlled clinical trial. Clinical Nutrition. 2016;35(3):615–625. doi:10.1016/j.clnu.2015.05.012
- Nie Y, Wang Y, Hui J, et al. The impact of flaxseed (Linum usitatissimum L.) oil supplementation on human health: a human-centric evidence-graded approach. Nutrients. 2025;17(11):1791. doi:10.3390/nu17111791
- Pan A, Chen M, Chowdhury R, et al. α-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis. American Journal of Clinical Nutrition. 2012;96(6):1262–1273. doi:10.3945/ajcn.112.044040
- National Center for Complementary and Integrative Health (NIH). Flaxseed and Flaxseed Oil. nccih.nih.gov
This article is for general education and is not medical advice. Food supplements are not intended to diagnose, treat, cure or prevent any disease. Consult a qualified healthcare professional before starting any supplement, particularly if you are pregnant, breastfeeding, have a medical condition or take medication.
