Coriander seed: one small diabetes trial and a lot of animal work

One randomized, double-blind trial (level B, a single study) used 1000 mg of coriander seed powder a day in capsules for 6 weeks in 40 adults with type 2 diabetes in Iran, and fasting glucose fell by 25.85 mg/dL and LDL cholesterol by 15.95 mg/dL against placebo. It ran at a single center, and 4 of 44 people dropped out. Everyone stayed on metformin or glibenclamide, so the fall came on top of those medicines, and body weight did not change. That dose is what the study used, not a safe or recommended amount. No upper limit for the powder is known to us. We have no card on whether adding it to glucose-lowering medicines can push blood sugar too low, so anyone on such medicines should talk to whoever prescribes them before adding capsules. Nobody has repeated it on a larger group, and 6 weeks says nothing about a year. The seed itself is dense on paper. Composition tables list 41.9 g fiber and 16.32 mg iron per 3.5 oz (100 g), though the UK and USDA records match to the hundredth, so they are almost certainly one measurement copied twice. A spice is eaten by the pinch, and per 3.5 oz (100 g) figures overstate what reaches a plate. We found no data on how much of that iron or calcium the body absorbs. Allergy is the caution the data supports: one case report describes anaphylaxis from coriander hidden in a flavored beer.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• The UK composition table lists coriander seeds at 41.9 g fiber, 16.32 mg iron, 709 mg calcium and 1270 mg potassium per 3.5 oz (100 g). — CoFID record 13-875 Coriander seeds (n = 1 record) Evidence E source
  Per 100 g: AOAC fiber 41.9 g, fat 17.8 g, protein 12.4 g, calcium 709 mg, iron 16.32 mg, magnesium 330 mg, potassium 1270 mg, zinc 4.7 mg, copper 0.97 mg, manganese 1.90 mg, sodium 35 mg
• The USDA reference record for coriander seed gives the same fiber, iron and copper values as the UK table, so the two do not count as independent measurements. — USDA SR Legacy FDC 170922 Spices, coriander seed (n = 1 record) Evidence E source
  Per 100 g: fiber 41.9 g, iron 16.32 mg, copper 0.975 mg (CoFID 41.9 g, 16.32 mg, 0.97 mg)

What it does to your health

• In a randomized trial of 40 adults with type 2 diabetes, 1000 mg of coriander seed powder a day for 6 weeks lowered fasting glucose by 25.85 mg/dL and LDL cholesterol by 15.95 mg/dL versus placebo. — 40 adults aged 30-60 with type 2 diabetes on metformin or glibenclamide, Tabriz, Iran; 500 mg capsules twice daily for 6 weeks (n = 40) Evidence B source
  Vs placebo: fasting glucose -25.85 mg/dL, insulin -0.60 uU/mL, HOMA-IR -1.30, total cholesterol -38.65 mg/dL, triglycerides -22.10 mg/dL, LDL-C -15.95 mg/dL (all P<0.001 except insulin P=0.003); no change in weight
• In a randomized trial of 80 hyperlipidemic patients, 2 g a day of coriander seed powder for 40 days improved lipids and systolic pressure, but the abstract gives no effect sizes. — 80 hyperlipidemic patients in 4 groups of 20 (garlic, coriander seed, mixture, placebo); 40 days of intervention plus 20 days follow-up (n = 80) Evidence B source
  Direction only: total cholesterol, LDL, triglycerides, systolic BP and BMI decreased and HDL increased (p<0.05); magnitudes not reported in the abstract
• In a pilot randomized trial in women with sensitive skin, 200 mg of virgin coriander seed oil a day for 56 days cut stripping-induced redness from 2.32 to 1.67 units, with no change on placebo. — Women aged 18-65 with sensitive, reactive skin; 30 per group, 20 (oil) and 18 (placebo) completed day-56 stress tests (n = 60) Evidence B source
  Redness delta a*: oil 2.32 to 1.67 a.u. at D56 (p<0.001 vs D0); placebo 2.78 to 2.61 a.u. (ns); between groups P=0.005 at D56

Safety, limits and interactions

• In the same 6-week trial of 1000 mg coriander seed powder a day, all 40 patients with type 2 diabetes completed it without any adverse events. — 40 adults with type 2 diabetes, 20 per group, 6 weeks (n = 40) Evidence B source
  0 adverse events reported in either group
• A case report describes anaphylaxis in a young woman from coriander added to beer as flavoring, where the spice acted as a hidden allergen. — One young woman, case report (n = 1) Evidence D source
  Anaphylaxis after coriander-flavored beer; first reported case of beer anaphylaxis due to coriander

Who this works differently for

• Skin-prick test records from a French allergy data bank found sensitization to coriander-family spices in 32% of prick tests in children and 23% in adults. — 589 food allergy cases in the CICBAA data bank, France; prick tests to native spices (n = 589) Evidence D source
  Apiaceae sensitization (coriander, caraway, fennel, celery): 32% of prick tests in children, 23% in adults; spice allergy 2% of all food allergies, 6.4% in adults; 1 coriander allergy

What is still unknown

• Lab and animal data dominate the evidence for coriander's heart benefits: of 18 studies in a 2021 review, 12 were animal studies and only 2 were clinical. — 18 studies on cardiovascular effects of Coriandrum sativum, searched to August 2021 (n = 18 studies) Evidence D source
  12 in vivo, 2 in vitro, 2 clinical, 2 mixed in vivo and in vitro

The bottom line

The wider heart reputation rests on thin ground. A 2021 review of 18 studies on coriander and the cardiovascular system found 12 done in animals, 2 in cells, 2 mixed, and only 2 in people. A second randomized trial gave 80 people with high blood lipids 2 g of seed powder a day for 40 days, in groups of 20. Its abstract reports a direction without sizes, and we could not reach the full text, so the result cannot be weighed. Coriander seed oil is a different product from the seed. In a pilot trial in women with sensitive skin, 200 mg of the oil a day for 56 days cut skin redness after tape stripping from 2.32 to 1.67 units, against 2.78 to 2.61 on placebo, with a gap between groups at P=0.005. A third of the volunteers dropped out during COVID-19, and the oil maker sponsored the study. Who should take care. In the 6-week diabetes trial, all 40 people finished with no adverse events, though with 20 people on coriander for six weeks a rare reaction such as allergy would not show up. Allergy is the real caution. One case report describes anaphylaxis in a young woman after a beer flavored with coriander, where the spice was a hidden ingredient. In a French allergy data bank of 589 food allergy cases, skin tests reacted to the coriander family, which includes caraway, fennel and celery, in 32% of tests in children and 23% in adults. A positive skin test is sensitization, which is not the same as allergy. We have no card on pregnancy, kidney disease or interactions with medicines, and the lack of a card is not evidence of safety. Coriander seed capsules and oil are dietary supplements, which in the US the FDA does not approve as medicines before they are sold. Anyone who takes medicines, especially for blood sugar, is pregnant or has a chronic illness should talk to whoever treats them before taking them.

Sources

1. crsd-r5-01 · CoFID 2021, dataset
   Coriander seeds (CoFID 13-875, group H): AOAC fibre 41.9 g; Fat 17.8 g; Protein 12.4 g; Water 8.9 g; Calcium 709 mg; Iron 16.32 mg; Magnesium 330 mg; Potassium 1270 mg; Zinc 4.7 mg; Copper 0.97 mg; Manganese 1.90 mg; Sodium 35 mg per 100 g
   CoFID 2021, Public Health England, code 13-875 (OGL v3.0) · checked 2026-10-02
2. crsd-r5-02 · USDA SR Legacy, dataset
   Spices, coriander seed (FDC 170922, sr_legacy, Spices and Herbs): Fiber, total dietary 41.9 g; Copper 0.975 mg; Iron 16.32 mg per 100 g
   USDA SR Legacy, FDC 170922 Spices, coriander seed · checked 2026-10-02
3. crsd-r5-03 · randomized controlled trial
   The key metabolic outcomes revealed marked improvements in the coriander group compared to the placebo: FBS decreased by 25.85 mg/dL (P<0.001), insulin by 0.60 µU/mL (P=0.003), and HOMA-IR by 1.30 units (P<0.001; Table 4). Lipid profile modifications included reductions in the levels of TC (−38.65 mg/dL), TG (−22.10 mg/dL), and LDL-C (−15.95 mg/dL) (P<0.001).
   Prev Nutr Food Sci, 2025 (PMC12765609) · checked 2026-10-02
4. crsd-r5-05 · randomized controlled trial
   The groups were randomly assigned to three supplements i.e. garlic powder (GP), coriander seed powder (CSP) and mixture (1:1 dry weight basis) of GP and CSP at a dose rate of 2 g/day. The fourth group was kept as placebo.
   Pak J Pharm Sci, 2018 · checked 2026-10-02
5. crsd-r5-06 · randomized controlled trial
   A statistically significant decrease was observed in the CSO group over time (D0: 2.32 ± 0.25 a.u., n = 30; D28: 1.95 ± 0.19 a.u., P = 0.044 versus D0, n = 30; D56: 1.67 ± 0.25 a.u., p < 0.001 versus D0, n = 20). Furthermore, there were significant differences between groups at D28 (P = 0.019) and D56 (P = 0.005).
   Food Nutr Res, 2022 (PMC9004245) · checked 2026-10-02
6. crsd-r5-04 · randomized controlled trial
   Finally, 40 T2DM patients (20 per group) completed this double-blind trial without any adverse events.
   Prev Nutr Food Sci, 2025 (PMC12765609) · checked 2026-10-02
7. crsd-r5-08 · case report
   We report on a case of a young woman who experienced anaphylaxis due to coriander-flavoured beer. This is the first case of beer anaphylaxis due to coriander, which had been added to the beer as aromatising substance.
   BMJ Case Rep, 2018 · checked 2026-10-02
8. crsd-r5-07 · case series
   Frequent sensitization to Apiaceae is observed: coriander, caraway, fennel, celery: 32% of prick-tests in children, 23% of prick-tests in adults.
   Allerg Immunol (Paris), 2002 · checked 2026-10-02
9. crsd-r5-09 · review
   Twelve in vivo, two in vitro, and two clinical studies in addition to two mixed in vivo and in vitro studies were retrieved.
   Molecules, 2021 · checked 2026-10-02