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Home / All About Herbs / About Flaxseed (and Flaxseed Oil) Monograph


© 2018 Steven Foster

A flaxseed monograph for the home

Latin Name: Linum usitatissimum

Common Names: flaxseed, flax, linseed

This flaxseed monograph provides basic information about flaxseed and flaxseed oil—common names, usefulness and safety, and resources for more information.


Flaxseed Basics

  • Over the thousands of years it’s been cultivated, flaxseed has had a variety of health and industrial uses. Around 500 B.C., Hippocrates wrote about flaxseed being a laxative, and pioneers in North America made flaxseed dressings for cuts and burns. Fiber from the plant is made into linen, and oil from the seed is used in paints, among other products.
  • Today, flaxseed and flaxseed oil are used as dietary supplements for constipation, diabetes, cholesterol, cancer, and other conditions.
  • Flaxseed is made into tablets, extracts, powder, and flour. The oil is also put in capsules.

Flaxseed in Health Research

  • There have been a number of studies in people of flaxseed and flaxseed oil, including their effect on hot flashes.

Flaxseed Research Summary

  • Flaxseed contains fiber, which generally helps with constipation. However, there’s little research on the effectiveness of flaxseed for constipation.
  • Studies of flaxseed and flaxseed oil to lower cholesterol levels have had mixed results. A 2009 research review found that flaxseed lowered cholesterol only in people with relatively high initial cholesterol levels.
  • Flaxseed doesn’t decrease hot flashes, studies from 2010 and 2012 suggest.
  • NCCIH is funding preliminary research on the potential role of substances in flaxseed for ovarian cancer, cardiovascular disease, metabolic syndrome, diabetes, asthma, and inflammation.

Flaxseed Safety

  • Don’t eat raw or unripe flaxseeds, which may contain potentially toxic compounds.
  • Flaxseed and flaxseed oil supplements seem to be well tolerated in limited amounts. Few side effects have been reported.
  • Avoid flaxseed and flaxseed oil during pregnancy as they may have mild hormonal effects. There’s little reliable information on whether it’s safe to use flaxseed when nursing.
  • Flaxseed, like any fiber supplement, should be taken with plenty of water, as it could worsen constipation or, in rare cases, cause an intestinal blockage. Both flaxseed and flaxseed oil can cause diarrhea.

Flaxseed References


PubMed Articles About Linum usitatissimum

Source: National Center for Biotechnology Information (NCBI)[Internet]. Bethesda (MD): National Library of Medicine (US), National Center for Biotechnology Information; [1988] – [cited 2018 Apr 5]. Available from:

Aitken-Saavedra, J., Chaves Tarquinio, SB., De Oliveira da Rosa, WL., Fernandes da Silva, A., Almeida Machado, BM., Santos Castro, I., Oliveira Wennesheimer, A., Morales-Bozo, I., Uchoa Vasconcelos, AC., Neutzling Gomes, AP., (2021) Effect of a Homemade Salivary Substitute Prepared Using Chamomile (.) Flower and Flax () Seed to Relieve Primary Burning Mouth Syndrome: A Preliminary Report.

To evaluate (1) the effect of a salivary substitute prepared using chamomile (.) flower and flax () seed to relieve Primary burning mouth syndrome (BMS) symptoms, (2) their effect on the inhibition of matrix metallopeptidase 2 (MMP2) and MMP9 metalloproteinases, and (3) their potential cellular cytotoxic effect. 40 women aging >40 years with diagnosis of primary BMS. Center of Diagnosis of Diseases of the Mouth, Federal University of Pelotas, Brazil. This was an open clinical trial where primary BMS patients used the homemade salivary. At the first appointment, after 30 and 60 days, the authors evaluated the pattern and intensity of BMS and xerostomia symptoms, and then determined and compared the unstimulated salivary flow rate (SFR), viscosity, and salivary pH. MMP2 and MMP9 activities in saliva and cytotoxicity were assessed using different concentrations of chamomile flower and flax seed separately. Subjects used the homemade salivary substitute for 3 months and were instructed to rinse their mouth three to four times daily for 1 min. A numeric rating scale to evaluate the intensity of burning sensation and xerostomia symptoms, salivary flow rate (SFR) to determine salivary volume, dynamic rheology technique for viscosity and a digital meter for salivary pH. MMP2 and MMP9 activities in saliva and cytotoxicity were assessed by zymography and cell viability assay respectively. After treatment, severity of BMS symptoms decreased, the SFR increased, salivary viscosity decreased, and severity of xerostomia sensation (in patients who reported having this symptom) improved ( < 0.05). Chamomile flower and flax seed had no effect on inhibiting MMP2 and MMP9 activities, and neither showed cellular cytotoxic effects. This homemade salivary substitute is an economical, viable, easily manipulated, noncytotoxic, and a practical alternative to relieve BMS symptoms.

Vuksan, V., Choleva, L., Jovanovski, E., Jenkins, AL., Au-Yeung, F., Dias, AG., Ho, HV., Zurbau, A., Duvnjak, L., (2018) Comparison of flax (Linum usitatissimum) and Salba-chia (Salvia hispanica L.) seeds on postprandial glycemia and satiety in healthy individuals: a randomized, controlled, crossover study.

Flax and Salba-chia seeds have risen in popularity owing to their favorable nutrient composition, including a high fiber content. Despite having comparable nutritional profiles, preliminary observations suggest differences in gelling properties, an attribute that may alter the kinetics of food digestion. Thus, we compared the effect of two seeds on postprandial glycemia and satiety scores.

Santiago, A., Ryland, D., Cui, S., Blewett, H., Aliani, M., (2019) Effect of milled flaxseed and storage conditions on sensory properties and selected bioactive compounds in banana and cinnamon muffins used in a clinical trial.

Muffins containing 0, 20, and 30 g of flaxseed were developed for a randomized, controlled cross-over trial on low-density lipoprotein (LDL) cholesterol lowering. The effect of milled flaxseed and storage (-20 °C for 1 and 6 months) of banana and cinnamon muffins on sensory attribute intensities, selected physical properties, bioactive concentrations, and acceptability by two groups - clinical trial participants and consumers - was investigated.

Setayesh, M., Sadeghifar, AR., Nakhaee, N., Kamalinejad, M., Rezaeizadeh, H., (2019) A Topical Gel From Flax Seed Oil Compared With Hand Splint in Carpal Tunnel Syndrome: A Randomized Clinical Trial.

This study compared the therapeutic effect of flax seed oil topical gel and hand splint in the treatment of carpal tunnel syndrome. This study was a randomized clinical trial. Forty-nine patients, 96 hands, with mild to moderate idiopathic carpal tunnel syndrome were divided into 2 groups randomly. One group was treated by topical gel and the other group by hand splint. Intensity of symptoms and function before and after intervention was measured via Boston Carpal Tunnel Questionnaire. After intervention, the ANCOVA showed a significant difference between the symptom and function scores of the 2 groups. In both cases, recovery was higher in the gel group ( P < .001). The topical use of flax seed oil gel is more effective in the improvement of symptoms and function of patients with mild to moderate carpal tunnel syndrome as compared with hand splint, and it can be introduced as an effective treatment.

Ebrahimi, F., Farzaei, MH., Bahramsoltani, R., Heydari, M., Naderinia, K., Rahimi, R., (2021) Plant-derived medicines for neuropathies: a comprehensive review of clinical evidence.

Neuropathy is defined as the damage to the peripheral or central nervous system accompanied by pain, numbness, or muscle weakness, which can be due to congenital diseases or environmental factors such as diabetes, trauma, or viral infections. As current treatments are not sufficiently able to control the disease, studies focusing on the identification and discovery of new therapeutic agents are necessary. Natural products have been used for a long time for the management of different neurological problems including neuropathies. The aim of the present study is to review the current clinical data on the beneficial effects of medicinal plants in neuropathy. Electronic databases including PubMed, Scopus, and Cochrane Library were searched with the keywords 'neuropathy' in the title/abstract and 'plant' or 'extract' or 'herb' in the whole text from inception until August 2017. From a total of 3679 papers, 22 studies were finally included. Medicinal plants were evaluated clinically in several types of neuropathy, including diabetic neuropathy, chemotherapy-induced peripheral neuropathy, carpal tunnel syndrome, and HIV-associated neuropathy. Some studies reported the improvement in pain, nerve function, nerve conduction velocity, and quality of life. Cannabis sativa (hemp), Linum usitatissimum (linseed oil), capsaicin, and a polyherbal Japanese formulation called Goshajinkigan had the most evidence regarding their clinical efficacy. Other investigated herbal medicines in neuropathy, such as Matricaria chamomilla (chamomile), Curcuma longa (turmeric), and Citrullus colocynthis (colocynth), had only one clinical trial. Thus, future studies are necessary to confirm the safety and efficacy of such natural medicines as a complementary or alternative treatment for neuropathy.