The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
General: Flaxseed oil is most often used in a liquid form, which contains approximately 7 grams of ALA and approximately 130 calories per 15 milliliters or 1 tablespoon. Flaxseed oil is available in a capsule form, which often contains 500 milligrams of ALA per 1,000 milligrams capsule (10 calories).
Whole or bruised (not ground) flaxseed may be mixed with water or juice and ingested. Generally, one tablespoon in this form may be mixed with 6-12 ounces of liquid and taken up to three times daily. Some studies have used up to 60-80 grams per kilogram of soluble flaxseed mucilage or fiber. These forms of flaxseed should not be confused with preparations of flaxseed oil.
In several studies, adults have consumed up to 50 grams of ground raw flaxseeds daily for periods not exceeding four weeks. Generally, the higher the dose, the greater the risk of gastrointestinal side effects. A dose of 50 grams of flaxseeds daily may correlate with 250 grams of flaxseed flour. In large doses, or when taken without enough water, flaxseed may cause bowel obstruction. At high temperatures, such as cooking, flaxseed oil and powder or flour will degrade.
For breast cancer, 10-25 grams of flaxseed or 5-25 grams of ground flaxseed has been taken by mouth daily for up to 16 weeks.
For breast pain (mastalgia), a muffin containing 25 grams of flaxseed has been taken by mouth daily for six months.
For constipation, 2-3 tablespoons of bulk seed mixed in 10 times the amount of water or 45 grams of bulk seed daily has been taken by mouth. Up to 15 grams of fiber from a flax fiber supplement has been taken by mouth for two weeks.
For diabetes, three capsules containing lignan (0.6 grams per capsule, which provided a total of 360 milligrams of isolated flaxseed lignan) have been taken by mouth daily for 12 weeks. Additionally, 40-50 grams of flaxseed, 32 grams of milled flaxseed, 13 grams of flaxseed oil, or 10 grams of flaxseed powder has been taken by mouth for up to 12 weeks.
For dry eye syndrome, 1-2 grams of flaxseed oil capsules have been taken by mouth daily for 180 days.
For enlarged prostate (benign prostatic hypertrophy), 300 and 600 milligrams of a flaxseed lignan extract containing 33% secoisolariciresinol diglucoside (SDG) have been taken by mouth for four months.
For exercise performance enhancement, 30 milliliters of flaxseed oil has been taken by mouth daily for 12 weeks.
For heart disease, 10-30 milliliters of flaxseed oil (containing 4.5 -13.5 grams of ALA) has been taken by mouth daily for 10-12 months.
For high blood pressure, 15-60 milliliters of flaxseed oil or three tablets containing 550 milligrams of flax extract have been taken by mouth daily for up to six months.
For high cholesterol, 20-50 grams of flaxseed (whole, ground, or defatted), flaxseed oil containing 1-38 grams of ALA, 5.2-16 grams or 60 milliliters of flaxseed oil, 200-600 milligrams of flaxseed lignan, 10 grams of flaxseed powder, flaxseed oil extract, and flaxseed-containing muffins, breads, and margarine have been used taken by mouth daily for 2-52 weeks.
For irritable bowel syndrome, 24 grams (two tablespoons) of whole flaxseed or ground flaxseed has been taken by mouth daily for four weeks. One tablespoon of whole or bruised seed mixed with 150 milliliters of liquid has reportedly been taken by mouth 2-3 times daily.
For lupus, 30 grams of flaxseed has been taken by mouth daily for four weeks.
For menopausal symptoms, 5-45 grams of flaxseed, ground flaxseed, or two 500 milligram capsules have been taken by mouth daily for up to 12 months.
For metabolic syndrome, 3-12 capsules of flaxseed oil (550 milligrams of ALA per capsule), 30 grams of flaxseed or 550 milligrams of flax extract have been taken by mouth daily for up to six months.
For obesity, 30 grams of flaxseed flour (5 grams of ALA and omega-3), 60 grams of flaxseed, a 300 milliliter flax drink, or seven tablets with flax fiber extract have been taken by mouth for up to 12 weeks. A diet of animal products from animals fed 5% linseed, as well as plant products consisting of 5 grams of extruded linseed flour, and bread with 4% extruded linseed flour, has been consumed daily for 90 days.
For osteoporosis, 40 grams of flaxseed or ground flaxseed, 30 milliliters flaxseed oil, or 550 milligrams of flax extract have been taken by mouth daily for up to 12 months.
For polycystic ovarian syndrome, six capsules of flaxseed oil containing 545 milligrams of ALA (Barleans Organic Oils, Ferndale, WA) have been taken by mouth daily for six weeks.
For premature infants, 2.2 grams of ALA has been taken by mouth daily as flax oil from week 17-27 of gestation until delivery.
For pressure ulcers, FlaxAid dressings were applied daily to the skin for 12 weeks.
For prostate cancer, a diet supplemented with 30 grams of flaxseed has been taken by mouth for at least 21 days before surgery.
For skin conditions (sensitivity), two capsules of flaxseed oil were taken with breakfast and two with dinner daily for 12 weeks. Additionally, four capsules of flaxseed oil (555.32 milligrams per capsule) have been taken by mouth daily for 12 weeks. Additionally, 30-100 grams of flaxseed flour may be mixed with warm or hot water to form a moist compress up to three times daily.
Flaxseeds have been used for foreign body removal in the eye by placing a single whole flaxseed under the eyelid and allowing the foreign body or mucus to adhere to it. This process may be unsafe, and it is suggested that a healthcare professional be consulted for removal of foreign bodies from the eye.
Children (under 18 years old)
For attention-deficit hyperactivity disorder (ADHD), flax oil with 200 milligrams of ALA content, along with 25 milligrams of vitamin C, has been taken by mouth twice daily for three months.
For bipolar disorder, dosing gradually increasing by 1-2 grams to a maximum total dose of six capsules twice daily (up to 6.5 grams of ALA) has been taken by mouth for 16 weeks.
For premature infants, a pillow filled with flaxseed on the chest for 15 minutes twice daily has been used for the first five days of life.
This evidence-based monograph was prepared by The Natural Standard Research Collaboration