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Herb library · Herb · Medicago sativa

Alfalfa

A plant eaten as sprouts and sold as leaf and seed supplements. It is promoted to increase breast milk, with no valid trials behind that, and its human research is thin.

Traditional use

Alfalfa seeds were used in the folk medicine of Iran and in traditional Persian medicine for men's fertility. Today the leaves and sprouts are sold in supplements, including mixtures promoted to increase breast milk supply, and the sprouts are often eaten raw.

What studies show

  • Limited

    Male infertility: one randomized, double-blind trial of 60 men found that 6 g a day of alfalfa seed powder for 12 weeks, added to vitamin E, improved sperm count, movement and shape more than vitamin E alone. The authors say larger trials are needed.

  • Insufficient

    Breast milk supply: alfalfa is included in products promoted to increase milk, but LactMed says no scientifically valid clinical trials support this use.

Be careful of

Cautions

  • ConditionPeople with lupus: worsening of systemic lupus erythematosus has been reported, possibly because a compound in alfalfa (L-canavanine) stimulates the immune system (LactMed). A 2025 review also lists alfalfa among herbs that may flare autoimmune skin diseases.
  • InteractionAlfalfa contains vitamin K, and LactMed advises people taking warfarin to avoid it.
  • NoteRaw or lightly cooked sprouts, including alfalfa sprouts, can carry Salmonella, Listeria and E. coli. FDA advises children, older adults, pregnant women and people with weakened immune systems to avoid raw or lightly cooked sprouts of any kind.
  • PregnancyThere are no data on the safety of alfalfa supplements in nursing mothers or infants. Galactogogues should not replace an assessment of what is affecting milk supply (LactMed).
  • NoteAlfalfa is generally well tolerated and FDA considers it generally recognized as safe as a food. In the seed trial, one man withdrew with bloating and one with a respiratory allergy.
  • Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.

Sources

  1. Alfalfa (LactMed, Drugs and Lactation Database) (opens in a new tab) · NIH · read September 25, 2026
  2. Effect of Medicago sativa seed powder (plus vitamin E vs. vitamin E alone) on semen analysis in men with idiopathic infertility: a double blind randomized clinical trial (opens in a new tab) · NIH · read September 25, 2026
  3. Identifying immunostimulatory herbal supplements that may flare autoimmune skin diseases: a systematic scoping review (opens in a new tab) · NIH · read September 25, 2026
  4. Selecting and Serving Produce Safely (opens in a new tab) · FDA · read September 25, 2026

Reviewed September 25, 2026.