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Alfalfa (Sprout & Leaf)

Medicago sativa
Evidence Level
Limited
2 Clinical Trials
5 Documented Benefits
2/5 Evidence Score

Alfalfa (Medicago sativa) is a deep-rooted legume traditionally used as a nutritive tonic and modern dietary supplement. The leaf and sprouts supply chlorophyll, carotenoids, vitamin K, calcium, magnesium, and phytoestrogenic isoflavones such as coumestrol and formononetin. It has a long folk history as a spring tonic, a cholesterol remedy, a galactogogue and a menopause remedy, none of which has been confirmed in a controlled trial of alfalfa on its own. Human evidence is thin and comes almost entirely from alfalfa seed rather than the leaf or sprout material most supplements contain: an uncontrolled 15-patient study used 120 g of heat-treated seed a day, and a 60-man randomized trial used 6 g of seed powder a day. No published trial has tested the 5 to 10 g leaf doses that are commonly sold. Two safety points matter more here than any benefit. Alfalfa seed and sprouts contain L-canavanine, which reproduced a lupus-like syndrome in monkeys and has been reported in human cases of lupus flare, so Health Canada contraindicates alfalfa herb above 900 mg a day in anyone with a history of systemic lupus erythematosus. And raw sprouts are a recurring source of Salmonella and E. coli O157:H7 outbreaks, so the FDA advises children, older adults, pregnant women and people with weakened immune systems not to eat them raw.

Studied Dose The doses actually tested in people are both alfalfa seed, not leaf: 40 g of heat-treated seed three times a day (120 g a day in total) for 8 weeks in the 1987 lipid study, and 6 g a day of seed powder for 12 weeks in the 2024 semen-quality trial. Commercial leaf products are usually sold at 5 to 10 g of dried leaf a day, or 500 to 1,000 mg of extract two or three times a day, and no trial has tested those amounts. Health Canada permits 9 to 30 g of dried herb top or leaf a day as a nutritive tonic, and contraindicates more than 900 mg a day for anyone with a history of systemic lupus erythematosus.
Active Compound Saponins, isoflavones (coumestrol, formononetin, genistein), chlorophyll, carotenoids, and vitamin K1. Alfalfa seed and sprouts also contain L-canavanine, which is not a benefit-bearing compound: it is the constituent linked to lupus-like autoimmunity. Alfalfa seed carries 6 to 16 mg of canavanine per gram of dry seed, stored almost entirely in the cotyledons, and the level falls as the seedling grows, so mature leaf carries far less than seed or sprouts do.

Benefits

LDL fell 18% in one small uncontrolled study of alfalfa seed

The one substantial human lipid study gave 15 patients with hyperlipoproteinemia 40 g of heat-prepared alfalfa seeds three times a day, 120 g in total, for 8 weeks. In the 11 patients with type II disease, median total cholesterol fell 17% and LDL cholesterol fell 18%, and apolipoprotein B fell 34%. There was no placebo group and no control arm, so part of that change could reflect the study itself rather than the seeds, and all values returned to baseline once the seeds were stopped. An earlier report by a different group found falling cholesterol in three volunteers eating alfalfa seed for three weeks, also with no control. The proposed mechanism is that alfalfa saponins bind cholesterol and bile acids in the gut so less is reabsorbed. No human study has tested alfalfa leaf or sprouts on blood lipids.

Supported by Trial 1

Provides nutritive minerals and vitamins

Alfalfa leaf supplies vitamin K1, calcium, magnesium, trace minerals, carotenoids and chlorophyll. The amount depends heavily on the form: USDA data put raw alfalfa sprouts at 30.5 micrograms of vitamin K1 per 100 g, which is about 10 micrograms in a one-cup serving. Dried leaf and pressed leaf tablets are far more concentrated, because the water has been removed, and they do not declare a vitamin K figure on the label. Anyone taking warfarin needs to treat alfalfa leaf products as a vitamin K source and not as a neutral green.

Supported by Trial 2, Trial 1

Menopause: tested only as a sage plus alfalfa combination

The single human study behind this claim gave 30 menopausal women a preparation made from sage leaf and alfalfa leaf extracts together, with no placebo group and no comparison arm. Hot flushes and night sweats stopped in 20 women and improved in the other 10. Because sage was given at the same time, and sage has hot-flush data of its own, nothing in that result can be assigned to alfalfa. No trial of alfalfa by itself has been published for menopausal symptoms. Alfalfa does contain the phytoestrogens coumestrol and formononetin, which bind estrogen receptors weakly, but that is chemistry rather than an effect measured in women taking alfalfa alone.

Supported by Trial 2

Antioxidant compounds, with no human antioxidant measurements

Alfalfa leaf contains chlorophyll, carotenoids and flavonoids, and these scavenge free radicals in test-tube assays. Health Canada allows a source-of-antioxidants claim on alfalfa herb on that compositional basis. No study has measured any marker of oxidative stress in a person taking alfalfa, so there is nothing to report about what it does to antioxidant status in a human body.

Supported by Trial 2, Trial 1

Traditional spring tonic use, untested

Alfalfa leaf has been taken as a spring tonic for its fibre, chlorophyll and bitter compounds, and folk sources describe a mild diuretic effect. None of this has been measured in a human study, and there is no evidence that alfalfa changes how the liver or kidneys clear anything.

Supported by Trial 2, Trial 1

Mechanism of action

1

Cholesterol binding via saponins

Alfalfa saponins form insoluble complexes with intestinal cholesterol and bile acids, reducing their reabsorption. This drives hepatic conversion of cholesterol into new bile acids. The step from that mechanism to a measured LDL drop in people rests on one uncontrolled study of alfalfa seed, and the saponin load of a leaf tablet is not the same as that of 120 g of seed a day.

2

Estrogen receptor binding by alfalfa isoflavones

Coumestrol and formononetin bind weakly to estrogen receptors, coumestrol with a preference for ER beta. That is receptor chemistry measured in the laboratory. No estrogen-dependent outcome has been measured in a person taking alfalfa on its own, so this is a proposed mechanism rather than an explanation of a demonstrated effect.

3

Vitamin K1 contribution

Alfalfa leaf carries phylloquinone (vitamin K1), the cofactor for gamma-carboxylation of clotting factors and of bone proteins such as osteocalcin. That is also the mechanism of the warfarin interaction: warfarin works by blocking vitamin K recycling, so extra vitamin K1 pushes the INR down and weakens anticoagulation. Raw sprouts are a mild source at about 30 micrograms per 100 g, but dried leaf and leaf tablets are much more concentrated and rarely declare their vitamin K content on the label.

4

Antioxidant scavenging by chlorophyll and carotenoids

Chlorophyll derivatives and carotenoids in alfalfa scavenge reactive oxygen species in laboratory assays and may bind certain dietary mutagens in the gut. Whether that changes antioxidant status in a person taking alfalfa has not been measured.

Clinical trials

1
Small trial on alfalfa seeds and lipids
PubMed

Open, uncontrolled study with no placebo arm. Heat-prepared alfalfa seeds, 40 g three times a day at mealtimes (120 g a day in total), for 8 weeks with the diet otherwise unchanged. Molgaard, von Schenck and Olsson, Atherosclerosis 1987.

15 patients with hyperlipoproteinemia: 8 type IIa, 3 type IIb and 4 type IV.

In the type II patients, median total cholesterol fell from 9.58 to 8.00 mmol/l (17%) and LDL cholesterol from 7.69 to 6.33 mmol/l (18%) at 8 weeks, with apolipoprotein B down 34%. Apolipoprotein A-I did not change. In two patients LDL cholesterol fell less than 5%. Body weight rose slightly, which the authors put down to the calories in 120 g of seed a day. All lipoprotein values returned to pretreatment levels after the seeds were stopped. With no control group, no randomisation and 15 patients, this is a preliminary observation rather than a demonstration of effect, and it used seed rather than the leaf or sprout material sold as alfalfa supplements.

2
Sage plus alfalfa combination in menopausal women, uncontrolled
PubMed

Open study of a plant product made from Salvia officinalis (sage) leaf and Medicago sativa (alfalfa) leaf extracts, taken for about 3 months. No placebo group and no alfalfa-only arm. De Leo and colleagues, Minerva Ginecologica 1998.

30 menopausal women with hot flushes and night sweats.

Hot flushes and night sweats disappeared completely in 20 of the 30 women, 4 had good improvement and 6 had some reduction. In the 8 women given TRH testing, prolactin and TSH responses rose after 3 months and the authors read this as a slight central antidopaminergic action; basal estradiol, LH, FSH, prolactin and TSH were unchanged. Because every woman received sage as well as alfalfa and there was no placebo group, none of this can be attributed to alfalfa.

Side effects and drug interactions

Common Potential side effects

Gastrointestinal upset such as gas or loose stools with high intake.
Photosensitivity is documented in animals rather than in people. Cattle, horses, sheep and laying hens fed alfalfa hay, silage or leaves have developed photosensitisation, and albino rats fed lucerne leaf protein concentrate did too; chlorophyll breakdown products are the suspected cause. No human case from an alfalfa supplement has been published.
Lupus-like autoimmune reactions attributed to L-canavanine. Cynomolgus monkeys fed alfalfa seeds or sprouts developed the blood and antibody abnormalities of systemic lupus erythematosus, and feeding L-canavanine on its own reactivated the syndrome in monkeys that had already had it. Human evidence is case-level: a volunteer eating alfalfa seed for a cholesterol study developed pancytopenia, and lupus flare has been reported with alfalfa tablets. A Swedish case-control study of 85 women with new lupus specifically asked about alfalfa sprout consumption, and sprouts are not among the risk factors it reports as significant, so this is not a demonstrated common-population risk. Health Canada contraindicates alfalfa herb above 900 mg a day for anyone with a history of systemic lupus erythematosus, and NIH's LactMed notes that worsening of lupus has been reported. Canavanine is concentrated in seed and sprouts, at 6 to 16 mg per gram of dry seed, and falls as the plant grows, so mature leaf carries far less; autoclaving the seed abolished the effect in the monkey experiments.
Foodborne illness from raw sprouts. Sprouting conditions let any Salmonella or E. coli O157:H7 present on the seed multiply past 10 million organisms per gram without changing how the sprouts look, and chlorine or other disinfectant washes do not eliminate them. The FDA advises children, older adults, pregnant women and people with weakened immune systems not to eat raw or lightly cooked sprouts of any kind, including alfalfa; cooking sprouts thoroughly kills the bacteria.
Allergic reactions in those sensitive to legumes.

Important Drug interactions

Warfarin and other vitamin K antagonists: alfalfa leaf supplies vitamin K1, which pushes the INR down and weakens anticoagulation. NIH's LactMed monograph states that alfalfa should be avoided by people taking warfarin, and Health Canada tells anyone on blood thinners to consult a practitioner before using alfalfa above 900 mg a day. Raw sprouts are a modest source at roughly 10 micrograms of vitamin K1 per cup, but dried leaf and leaf tablets are much more concentrated and rarely declare their vitamin K content, which makes the dose unpredictable rather than merely high.
Possible additive effects with estrogen-based hormone therapies.
Immunosuppressants after organ transplant: a case report in the American Journal of Transplantation describes late acute rejection of a kidney transplant in a woman who had been taking herbal medicines, with alfalfa and black cohosh identified as the herbs. Two herbs were taken together and the authors describe the link as possible rather than established, so this is one case and not a demonstrated interaction. Transplant recipients should not add alfalfa without asking their transplant team.
Blood-glucose-lowering medications: this caution rests on animal data only. Alfalfa leaf in the diet reduced the rise in blood glucose in streptozotocin-diabetic mice, and alfalfa sprout extracts lowered glucose in diabetic rats. Blood glucose has not been measured in a person taking alfalfa, so any effect in people is of unknown size. Anyone on insulin or an oral glucose-lowering drug should monitor as a precaution.

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Frequently asked questions about Alfalfa (Sprout & Leaf)

What is alfalfa used for?

Alfalfa is a nutrient-rich legume and herb used as a green superfood and supplement, valued for vitamins (including vitamin K), minerals, and chlorophyll. It is mostly used for general nutrition. The cholesterol claim rests on one uncontrolled 15-patient study of 120 g of alfalfa seed a day, not on the leaf tablets usually sold. Claims that it alkalises the body have no basis: blood pH is tightly regulated and food does not move it.

What is alfalfa good for?

It is used mainly as a general nutritional supplement and a source of vitamin K1, carotenoids and minerals. The cholesterol evidence is one uncontrolled study of alfalfa seed at 120 g a day, and the menopause evidence is a sage plus alfalfa combination, so neither supports the leaf tablets on the shelf. Its vitamin K1 content matters for anyone taking warfarin.

How much alfalfa should I take?

It is sold as tablets, powder and tea. Health Canada permits 9 to 30 g of dried herb top or leaf a day as a nutritive tonic, and applies the lupus contraindication and the blood-thinner caution to any product above 900 mg a day. No trial has established an effective dose of alfalfa leaf for any outcome: the two human trials used alfalfa seed, at 120 g a day and 6 g a day.

Is alfalfa safe?

Alfalfa leaf is generally well tolerated, and the FDA treats it as generally recognised as safe as a food. Three cautions matter. It supplies vitamin K1, so it interferes with warfarin, and NIH's LactMed says people on warfarin should avoid it. Its seeds and sprouts contain L-canavanine, which produced a lupus-like syndrome in monkeys and has been linked in human case reports to lupus flare and to one case of pancytopenia, so Health Canada says do not use more than 900 mg a day if you have a history of systemic lupus erythematosus. And raw sprouts have caused repeated Salmonella and E. coli outbreaks, so the FDA tells children, older adults, pregnant women and immunocompromised people not to eat them raw. Health Canada also advises against alfalfa supplements during pregnancy and breastfeeding.

What is Alfalfa?

Alfalfa (Medicago sativa) is a deep-rooted legume traditionally used as a nutritive tonic and modern dietary supplement. The leaf and sprouts supply chlorophyll, carotenoids, vitamin K, calcium, magnesium, and phytoestrogenic isoflavones such as coumestrol and formononetin.

What is the recommended dosage of Alfalfa?

The clinically studied dose is The doses actually tested in people are both alfalfa seed, not leaf: 40 g of heat-treated seed three times a day (120 g a day in total) for 8 weeks in the 1987 lipid study, and 6 g a day of seed powder for 12 weeks in the 2024 semen-quality trial. Always follow the product label and check with a healthcare provider for personal advice.

Is Alfalfa safe, and does it have side effects?

For most healthy adults, Alfalfa is well tolerated at studied doses. Reported effects can include: Gastrointestinal upset such as gas or loose stools with high intake. Photosensitivity is documented in animals rather than in people. Cattle, horses, sheep and laying hens fed alfalfa hay, silage or leaves have developed photosensitisation, and albino rats fed lucerne leaf protei… It may also interact with some medications. Alfalfa is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Alfalfa interact with any medications?

Possible interactions include: Warfarin and other vitamin K antagonists: alfalfa leaf supplies vitamin K1, which pushes the INR down and weakens anticoagulation. NIH's LactMed monograph states that alfalfa should be avoided by people taking warfarin, and Health Canada tells anyone on blood thinners to consult… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Alfalfa?

NutraSmarts rates the evidence for Alfalfa as Limited (2 out of 5). It is backed by 2 clinical trials and 16 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(16 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Mölgaard J, von Schenck H, Olsson AG. Alfalfa seeds lower low density lipoprotein cholesterol and apolipoprotein B concentrations in patients with type II hyperlipoproteinemia. Atherosclerosis. 1987;65(1-2):173-9. doi: 10.1016/0021-9150(87)90019-0.PubMedUsed to support: Fifteen patients with hyperlipoproteinemia took 40 g of heat-prepared alfalfa seeds three times a day, 120 g in total, for 8 weeks with the diet otherwise unchanged. In the type II patients, median total cholesterol fell 17% (9.58 to 8.00 mmol/l) and LDL cholesterol 18% (7.69 to 6.33 mmol/l), and apolipoprotein B fell 34%; apolipoprotein A-I did not change. Two patients had less than a 5% LDL response. Body weight rose slightly, which the authors attributed to the calories in the seeds, and all lipoprotein values returned to pretreatment levels after the seeds were stopped. The study was open and uncontrolled with no placebo group, and it used seed rather than leaf or sprouts.
  2. De Leo V, Lanzetta D, Cazzavacca R, Morgante G. [Treatment of neurovegetative menopausal symptoms with a phytotherapeutic agent]. Minerva Ginecol. 1998;50(5):207-11..PubMedUsed to support: Thirty menopausal women took an open-label preparation made from sage (Salvia officinalis) leaf and alfalfa (Medicago sativa) leaf extracts for about three months, with no placebo group and no alfalfa-only arm. Hot flushes and night sweats disappeared completely in 20 women, 4 improved markedly and 6 improved somewhat. In the 8 women tested, TRH-stimulated prolactin and TSH responses rose, which the authors interpreted as a slight central antidopaminergic action, while basal estradiol, LH, FSH, prolactin and TSH were unchanged. Because sage and alfalfa were given together and there was no control arm, the result cannot be attributed to alfalfa.
  3. Swanston-Flatt SK, Day C, Bailey CJ, Flatt PR. Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice. Diabetologia. 1990;33(8):462-4. doi: 10.1007/BF00405106.PubMedUsed to support: Mouse study. Dried alfalfa leaf supplied in the diet at 6.25% by weight, or as a decoction in place of drinking water, reduced the rise in blood glucose as streptozotocin diabetes developed and briefly blunted the fall in plasma insulin. Ten other traditional plants were tested alongside it. Nothing was measured in people, and no human study has tested alfalfa on blood glucose.
  4. Seida A, El-Hefnawy H, Abou-Hussein D, Mokhtar FA, Abdel-Naim A. Evaluation of Medicago sativa L. sprouts as antihyperlipidemic and antihyperglycemic agent. Pak J Pharm Sci. 2015;28(6):2061-74..PubMedUsed to support: Rat study published in a minor pharmacy journal. In streptozotocin-diabetic rats, a methanolic extract of alfalfa sprouts at 500 mg/kg a day, together with its petroleum ether fraction at 32.5 mg and its butanol fraction at 60 mg, lowered triglycerides, total cholesterol, LDL and VLDL over 4 weeks compared with rosuvastatin; the petroleum ether fraction was the most active, at a 12.23% reduction. The ethyl acetate fraction was the most active against blood glucose compared with metformin. Nine compounds were isolated from the active fractions. No human data followed, and 500 mg/kg in a rat is far above anything a person takes.
  5. Malinow MR, Bardana EJ Jr, Goodnight SH Jr. Pancytopenia during ingestion of alfalfa seeds. Lancet. 1981;1(8220 Pt 1):615. Case report letter..PubMedUsed to support: A case report of pancytopenia developing in a volunteer who was eating alfalfa seeds. This human observation is what prompted the primate feeding experiments on alfalfa and lupus.
  6. Malinow MR, McLaughlin P, Bardana EJ Jr, Craig S. Elimination of toxicity from diets containing alfalfa seeds. Food Chem Toxicol. 1984;22(7):583-7. doi: 10.1016/0278-6915(84)90230-8.PubMedUsed to support: Cynomolgus macaques fed autoclaved alfalfa seeds for up to a year showed none of the lupus-like blood and antibody changes that raw seeds produced in earlier experiments, and the autoclaved seeds still lowered cholesterol. Heat treatment therefore separates the cholesterol effect from the autoimmune effect in this primate model.
  7. Roberts JL, Hayashi JA. Exacerbation of SLE associated with alfalfa ingestion. N Engl J Med. 1983;308(22):1361. Case report letter..PubMedUsed to support: A case report letter describing exacerbation of systemic lupus erythematosus associated with alfalfa ingestion. Case reports show that the association has been observed in people; they do not establish how often it happens or in whom.
  8. Malinow MR, Bardana EJ Jr, Pirofsky B, Craig S, McLaughlin P. Systemic lupus erythematosus-like syndrome in monkeys fed alfalfa sprouts: role of a nonprotein amino acid. Science. 1982;216(4544):415-7. doi: 10.1126/science.7071589.PubMedUsed to support: Cynomolgus macaques fed alfalfa sprouts developed the blood and antibody abnormalities seen in human systemic lupus erythematosus. Feeding L-canavanine sulfate on its own then reactivated the syndrome in monkeys in which it had already been induced by alfalfa seeds or sprouts, which identifies canavanine as the responsible constituent. This is primate evidence, not human evidence.
  9. Malinow MR, McLaughlin P, Stafford C. Alfalfa seeds: effects on cholesterol metabolism. Experientia. 1980;36(5):562-4. doi: 10.1007/BF01965801.PubMedUsed to support: Plasma cholesterol fell in three human volunteers eating diets containing alfalfa seeds for three weeks, with no signs of toxicity on the serum tests done at the time. The rest of the paper is rat work, in which alfalfa seeds lowered plasma cholesterol, reduced intestinal absorption of both dietary and endogenous cholesterol, and increased faecal biliary excretion. Three uncontrolled subjects is the other half of the human lipid literature on alfalfa.
  10. Taormina PJ, Beuchat LR, Slutsker L. Infections associated with eating seed sprouts: an international concern. Emerg Infect Dis. 1999;5(5):626-34. doi: 10.3201/eid0505.990503.PubMedUsed to support: CDC review of Salmonella and E. coli O157:H7 outbreaks traced to raw seed sprouts. Pathogens can exceed 10 million per gram of sprouts grown from contaminated seed without any visible change in the sprouts, and treating seeds or sprouts with chlorinated water or other disinfectants fails to eliminate them. The authors advise that people at high risk of severe infection, specifically older adults, children and the immunocompromised, should not eat raw sprouts.
  11. Bengtsson AA, Rylander L, Hagmar L, Nived O, Sturfelt G. Risk factors for developing systemic lupus erythematosus: a case-control study in southern Sweden. Rheumatology (Oxford). 2002;41(5):563-71. doi: 10.1093/rheumatology/41.5.563.PubMedUsed to support: Case-control study of 85 women with newly diagnosed systemic lupus erythematosus and 205 matched controls in southern Sweden, whose questionnaire asked specifically about alfalfa (lucerne) sprout consumption. The factors reported as significantly associated with lupus were a history of hypertension (OR 3.7), drug allergy (OR 3.6), a sun-sensitive skin type (OR 2.3) and a family history of lupus (OR 6.8), while alcohol consumption was inversely associated. Alfalfa sprouts are not among the significant risk factors the study reports.
  12. Light TD, Light JA. Acute renal transplant rejection possibly related to herbal medications. Am J Transplant. 2003;2003;3(12):1608-9.PubMedUsed to support: Case report of late acute rejection of a kidney transplant in a middle-aged woman after exposure to two herbal medicines; the record identifies alfalfa (Medicago sativa) and black cohosh (Cimicifuga) as the herbs, both listed for adverse effects. Because two herbs were taken together and the authors describe the association as possible rather than established, this is a single case rather than a demonstrated interaction, but it is the reason transplant recipients on immunosuppressants are told not to add alfalfa without asking their transplant team.
  13. Akaogi J, Barker T, Kuroda Y, Nacionales DC, Yamasaki Y, Stevens BR, Reeves WH, Satoh M. Role of non-protein amino acid L-canavanine in autoimmunity. Autoimmun Rev. 2006;5(6):429-35. doi: 10.1016/j.autrev.2005.12.004.PubMedUsed to support: Review of the alfalfa and lupus evidence. The link was first noticed in a volunteer who developed lupus-like autoimmunity while eating alfalfa seed for a cholesterol study, and was then reproduced in monkeys fed alfalfa sprouts, with relapse on re-challenge with L-canavanine. The authors state that induction or exacerbation of lupus by alfalfa tablets has been reported in only a few cases and remains controversial, that epidemiological studies are sparse, and that mouse results differ by strain, with NZB/W F1, NZB and DBA/2 mice affected but BALB/c mice not. The proposed mechanism is that canavanine substitutes for arginine during protein synthesis and produces misfolded canavanyl proteins.
  14. Miersch J, Jühlke C, Sternkopf G, Krauss GJ. Metabolism and exudation of canavanine during development of alfalfa (Medicago sativa L. cv. verko). J Chem Ecol. 1992;1992;18(11):2117-29.PubMedUsed to support: Plant chemistry. L-canavanine was found in all 26 alfalfa cultivars examined, at 6 to 16 mg per gram of dry seed, where it made up more than 70% of total soluble nitrogen and was stored almost entirely in the cotyledons. It rose about threefold during the first 24 hours of sprouting and was then metabolised rapidly over the following weeks of seedling growth. This is why alfalfa seed and sprouts carry far more canavanine than mature leaf does.
  15. Drugs and Lactation Database (LactMed). Bethesda (MD): National Institute of Child Health and Human Development. Alfalfa. Drugs and Lactation Database (LactMed) [Internet], NCBI Bookshelf. 2021;Record updated 21 June 2021..PubMedUsed to support: NIH monograph on alfalfa. It states that no scientifically valid clinical trials support alfalfa as a galactogogue, that no data exist on excretion of alfalfa constituents into breastmilk or on safety in nursing mothers and infants, that alfalfa is generally recognised as safe as a food by the FDA, that worsening of systemic lupus erythematosus has been reported and is attributed to L-canavanine, and that because of its vitamin K content alfalfa should be avoided by people taking warfarin.
  16. Shahmirzadi AS, Shafi H, Shirafkan H, Memariani Z, Gorji N, Moeini R. 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. J Ethnopharmacol. 2024;322:117606. doi: 10.1016/j.jep.2023.117606.PubMedUsed to support: Double-blind randomized trial in 60 men with idiopathic infertility. Everyone took vitamin E 100 units; half also took 6 g a day of alfalfa seed powder and half took placebo, for 12 weeks. Sperm count rose from 36.2 to 48.5 million/ml on alfalfa versus 39.5 to 41.2 million/ml on placebo, normal morphology from 1.8% to 2.6% versus 2.0% to 2.6%, and motility from 36.5% to 39.7% versus 39.3% to 38.1%, all favouring alfalfa (p = 0.00, 0.01 and 0.04). Semen volume fell in both groups. There were four pregnancies in the alfalfa group and none on placebo. One man withdrew with abdominal bloating and one with a respiratory allergy. This is a single small trial, it used alfalfa seed rather than leaf or sprouts, and it has not been replicated.