Fenugreek is one of the most popular supplements used to increase milk supply, and while some studies show promising results, women taking thyroid medication should avoid it or carefully monitor their thyroid levels if they choose to use it.
As we’ve written about before (Do Supplements Really Work To Increase Milk Supply?), there are a number of supplements promoted to breastfeeding mothers to improve their milk production, with varied results. Fenugreek has been used for many years to promote wellness, increase milk supply and help with inflammation (particularly arthritis and urethritis). It’s a member of the pea family, sometimes used in artificial maple flavoring and a common ingredient in Indian and Chinese cooking.
A meta-analysis (which is a study that looks at all of the studies together to draw a conclusion) showed that it was superior to placebos and can help increase a woman’s milk supply, within as little as 24-72 hours. There are many different ways to take it: teas, capsules, liquid, seeds and powders. The recommended dose of fenugreek is 2-3 capsules (580-610 mg per capsule) 3-4 times per day, and it may be discontinued once milk supply has increased to the desired level.
It’s not clear exactly how fenugreek works, but some have proposed that it increases sweating and the breast is essentially a large sweat gland. Others have suggested that it increases certain naturally occuring hormones that stimulate milk production.
Fenugreek is listed as generally recognized as safe (GRAS) by the Food and Drug Administration.
While there is little published research on the side effects of fenugreek, some generalized side effects that have been reported include nausea, headaches, vomiting, increased gas and gastrointestinal motility with loose stools. Some women have reported increased breast congestion and a maple-like taste to breast milk. As with all dietary supplements, it’s important for mothers to be aware of side effects and to monitor themselves and their infants. They should discuss supplements that they are taking with their primary care providers and lactation consultants.
That’s especially important for women who take thyroid medication, who should be careful when taking fenugreek and consider monitoring their thyroid functions carefully while taking it. Some women who have trouble conceiving are placed on thyroid medication if their doctors detect hypothyroidism (and underactive thyroid gland), which is often continued during pregnancy. Many women with normal thyroid levels and no difficulties with conception develop thyroid abnormalities during pregnancy and are placed on levothyroxine (or equivalent) medication. Other women experience changes in their thyroid hormones during pregnancy.
While there isn’t much published research on the efficacy and safety of taking fenugreek in women with thyroid conditions, animal studies have shown that fenugreek decreased blood T3 levels when given to mice and rats and also created hypoglycemic effects (low blood sugar). It’s not clear why, but the ingestion of fenugreek by mice and rats inhibited T3 synthesis in mice and rats (References 1 and 3). Another study similarly found that fenugreek when administered to rats showed changes in T3, T4, glucose levels as well as G-6-phosphatase levels ( References 2 and 4).
Based on data from animal studies, it’s recommend to proceed with caution and perhaps even avoid fenugreek if you are struggling with regulation of thyroid levels after pregnancy and during lactation. I would also recommend that if someone is taking fenugreek regularly, even if they have never been found to have had a thyroid problem, that they have their thyroid functions tests measured just to be safe.
Bottom Line: Fenugreek is listed as generally recognized as safe (GRAS) by the FDA and as long as mothers are aware of the possible side effects, this is a good option to try to increase supply. However, mothers with thyroid conditions should proceed cautiously and consult with their physician before taking a fenugreek supplement.
Panda S, Tahiliani P., Kar A, Inhibition of Triiodothyronine Production by Fenugreek Seed Extract in Mice and Rats. Pharmacological Research, Vol 40., no 5, 1999
Tahiliani P., Kar A., The Combined Effects of Trigonella and Allium Extracts in the Regulation of Hyperthyroidism in Rats. Phytomedicine 10:665-68, 2003
Tahiliani P., Kar A., Mitigation of Thyroxine-Induced Hyperglycemia by Two Plant Extracts. Phytotherapy Research 17, 294-96, 2003
El-Wakf A., Hassan H., Mahmoud A., Habza M. Fenugreek Potent Activity Against Nitrate-Induced Diabetes in Young Rats and Adult Male Rtas. Cytotechnology 67:437-47, 2015.