Background

Flaxseed oil comes from flaxseed (Linum usitatissimum). It is a good source of an essential omega-3 fatty acid called alpha-linolenic acid (ALA).

The alpha-linolenic acid and other chemicals in flaxseed oil seem to decrease swelling, which is why some people use it for conditions that involve inflammation, such as rheumatoid arthritis.

Flaxseed oil is used for heart disease, high blood pressure, high levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia), and many other conditions, but there is no good scientific evidence to support these uses.

Flaxseed oil has different effects than whole or ground flaxseed. See Flaxseed for more information.

Safety Safety definitions

When taken by mouth: Flaxseed oil is likely safe for most adults. Supplements containing 2 grams of flaxseed oil daily have been used safely for up to 6 months. Higher doses of up to 24 grams daily have also been used safely for up to 7 weeks. These larger doses can cause side effects such as loose stools and diarrhea. Allergic reactions are also possible.

When applied to the skin: Flaxseed oil is possibly safe when used short-term. Flaxseed oil has been used safely on the wrist for up to 4 weeks.

When applied into the eye: Flaxseed oil is possibly safe when applied into the eye short-term. Eye drops containing flaxseed oil have been used safely for up to 3 months. Redness and itching may occur in some people.

Special Precautions & Warnings:

Pregnancy: Flaxseed oil is possibly safe when taken by mouth in doses of up to 2 grams daily for up to 6 weeks during pregnancy. But using flaxseed oil during the second or third trimester has been linked with an increased risk of giving birth prematurely.

Breast-feeding: There isn't enough reliable information to know if flaxseed oil is safe to use when breast-feeding. Stay on the safe side and avoid use.

Children: Flaxseed oil is possibly safe for children when taken by mouth, short-term. Flaxseed oil has been safely taken by mouth for up to 3 months by children about 7-8 years old.

Surgery: Flaxseed oil might increase the risk of bleeding during and after surgery. Stop using it at least 2 weeks before a scheduled surgery.

Effectiveness

Dosing & administration

Flaxseed oil has most often been used by adults in doses of 1-2 grams by mouth daily for up to 6 months. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Interactions with pharmaceuticals

Ezetimibe (Zetia)

Interaction Rating=Moderate Be cautious with this combination.

Flaxseed oil contains alpha-linolenic acid. Taking flaxseed oil and ezetimibe together can prevent the body from absorbing alpha-linolenic acid from flaxseed oil. If you are taking ezetimibe, talk to your doctor before taking flaxseed oil.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating=Moderate Be cautious with this combination.

Flaxseed oil might lower blood pressure. Taking flaxseed along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Flaxseed oil might slow blood clotting. Taking flaxseed along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Interactions with herbs & supplements

Herbs and supplements that might lower blood pressure: Flaxseed oil might lower blood pressure. Taking it with other supplements that have the same effect might cause blood pressure to drop too much. Examples of supplements with this effect include andrographis, casein peptides, L-arginine, niacin, and stinging nettle.
Herbs and supplements that might slow blood clotting: Flaxseed oil might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Interactions with foods

There are no known interactions with foods.