Bay leaf: one small diabetes trial and a leaf you take out of the pot

The main human evidence for bay leaf is one 2009 trial in Pakistan. Forty adults with type 2 diabetes, already on sulfonylurea and metformin, took 1, 2 or 3 g a day of ground bay leaf in capsules for 30 days. Fasting glucose fell by 21 to 26% in all three groups, with no significant change on placebo. There were 10 people per group, the paper does not describe blinding, and we found no replication since. Participants reported no significant side effects, but the paper does not say whether anyone had low blood sugar or how side effects were recorded, and 10 people per group for 30 days cannot settle that. The US National Center for Complementary and Integrative Health advises people with diabetes to talk with their health care provider before taking a supplement, because some supplements can interact with medicines, and not to take one instead of diabetes medicine. The same trial reported LDL cholesterol down 32 to 40%, an effect so large from a gram or two of leaf that it needs repeating before anyone relies on it. Capsules of ground leaf are also a different exposure from cooking, where a whole leaf simmers in the pot and comes out before serving. Dried bay leaf lists 43 mg of iron per 3.5 oz (100 g). A crumbled teaspoon weighs 0.6 g and gives about 0.26 mg.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Dried bay leaf lists 43 mg of iron per 3.5 oz (100 g), but a crumbled teaspoon weighs 0.6 g, so a dish gets about 0.26 mg from it, and usually the leaf is removed before eating. — USDA SR Legacy record Spices, bay leaf (FDC 170917) and CoFID 2021 Bay leaf, dried (13-806) Evidence E source
  Per 100 g: iron 43 mg (USDA and CoFID agree), calcium 834 mg (CoFID 830), fiber 26.3 g, vitamin B6 1.74 mg; per 1 tsp crumbled (0.6 g): iron about 0.26 mg, calcium about 5 mg (recalculated)

What it does to your health

• In a 30-day RCT in 40 people with type 2 diabetes, 1 to 3 g a day of ground bay leaf in capsules lowered fasting glucose by 21 to 26%, with no change on placebo. — 40 adults aged 40 or more with type 2 diabetes (18 men, 22 women) on sulfonylurea and metformin, randomized to 1, 2 or 3 g/day ground bay leaf or corn-flour placebo for 30 days, then 10-day washout, Peshawar, Pakistan (n = 40) Evidence B source
  Fasting serum glucose down 21 to 26% after 30 days in all three bay leaf groups; no significant change with placebo
• The same trial reported LDL cholesterol falling by 32 to 40% after 30 days of bay leaf capsules. — 40 adults with type 2 diabetes, 1, 2 or 3 g/day ground bay leaf or placebo for 30 days (n = 40) Evidence B source
  LDL cholesterol down 32 to 40% after 30 days, significant in all three groups from day 20; still 35% lower 10 days after stopping in the 3 g group
• In a crossover RCT in 12 men with overweight, adding 6 g of a 13-spice blend that included bay leaf to a fatty meal reduced a marker of post-meal inflammation. — 12 nonsmoking men aged 40 to 65 with overweight or obesity and at least one CVD risk factor, high-fat high-carbohydrate meal with 0, 2 or 6 g spice blend (n = 12) Evidence B source
  IL-1beta secretion from stimulated blood cells attenuated at 240 min with 6 g blend, not with 2 g

Safety, limits and interactions

• The EU food safety agency notes that bay laurel leaf oil contains about 3% methyleugenol, a compound that is genotoxic and carcinogenic in rodents. — EFSA FEEDAP Panel assessment of laurel leaf oil from Laurus nobilis leaves, six production batches Evidence E source
  Methyleugenol 3.1% of the oil on average (range 2.3 to 4.0%)

Who this works differently for

• Those results come from people already on diabetes drugs: the trial added bay leaf on top of sulfonylurea and metformin, with no one on insulin or statins. — 40 adults with type 2 diabetes aged 40 or more, BMI up to 35, not on insulin, on sulfonylurea and metformin (n = 40) Evidence B source
  Bay leaf effects measured in addition to unchanged diabetes medication
• In the 30-day trial of 1 to 3 g a day of ground bay leaf in 40 people on sulfonylurea and metformin, participants reported no significant side effects. The paper does not say whether anyone had low blood sugar or how side effects were recorded. — 40 adults with type 2 diabetes on sulfonylurea and metformin, 1, 2 or 3 g/day ground bay leaf in capsules or placebo for 30 days, medication unchanged (n = 40) Evidence B source
  All capsules consumed; no significant side effects reported; no problems associated with 1 to 3 g a day; hypoglycemia not reported either way
• The US National Center for Complementary and Integrative Health advises people with diabetes to talk with their health care provider before taking a dietary supplement, because some supplements can interact with medicines, and not to take a supplement instead of diabetes medicine. — people with type 2 diabetes considering dietary supplements Evidence E source
  Talk with a health care provider before taking a supplement; some supplements can interact with medicines; do not replace diabetes medicine with a supplement

What is still unknown

• EFSA had no individual consumption data for bay leaf and relied on a flavor handbook estimate of 0.27 mg per kg body weight a day for laurel leaves and berries. — EFSA FEEDAP Panel, consumer safety section of the laurel leaf oil opinion Evidence E source
  Exposure estimate 0.27 mg/kg bw per day for laurel leaves and berries; no individual consumption figures
• Most of the rest of the bay leaf evidence is animal work: 1 g of dried bay leaf per kg of feed lowered cholesterol and glucose in 120 growing rabbits. — 120 New Zealand white male rabbits aged 35 days, four groups of 30, with or without added pig fat and 1 g/kg dried bay leaf (n = 120) Evidence D source
  Lower glucose, total and LDL cholesterol, triglycerides, ALT and AST, higher HDL with bay leaf meal

The bottom line

Bay leaf also appears in a trial of a 13-spice blend. In 12 men aged 40 to 65 with overweight and at least one cardiovascular risk factor, 6 g of the blend added to a fatty meal dampened IL-1beta release from stimulated blood cells at 240 minutes, and 2 g did not. Bay leaf was one of 13 spices, so its own share cannot be separated, and this was a secondary lab measure. Most of the remaining evidence is animal work. In 120 growing rabbits, 1 g of dried bay leaf per kg of feed lowered glucose and total and LDL cholesterol, which points the same way as the human trial without showing that it applies to people. We found no study on how bay leaf is absorbed or on what cooking changes in it. Beyond that one trial we found no safety data on ground bay leaf in capsules. The one regulatory flag concerns the oil. EFSA notes that laurel leaf oil contains about 3.1% methyleugenol (range 2.3 to 4.0%), a compound genotoxic and carcinogenic in rodents. That opinion concerns the concentrated essential oil used as a feed additive, not a leaf simmered in a stew. EFSA had no individual consumption data for bay and relied on a flavor handbook estimate of 0.27 mg per kg body weight a day for laurel leaves and berries, which shows how little is measured. The diabetes results were measured on top of sulfonylurea and metformin, and they say nothing about people on insulin or without diabetes. We found no study on bay leaf in pregnancy, in children or on allergy, so we cannot say whether capsule doses are safe for them.

Sources

1. bayl-r2-01 · USDA FoodData Central SR Legacy and CoFID, dataset
   Spices, bay leaf (FDC 170917, SR Legacy, Spices and Herbs): iron 43 mg per 100 g = 239% DV; vitamin B6 1.74 mg = 102% DV; fiber 26.3 g = 94% DV; calcium 834 mg; portion 1 tsp, crumbled 0.6 g; CoFID 13-806 Bay leaf, dried: Iron 43.00 mg, Calcium 830 mg; Foundation samples 0
   USDA FoodData Central, SR Legacy, FDC 170917; CoFID 2021, code 13-806 · checked 2026-09-29
2. bayl-r2-02 · randomized controlled trial in humans
   All three levels of bay leaves tested led to decreased fasting serum glucose (Table 1) ranging from 21 to 26% after 30 days.
   J Clin Biochem Nutr, 2009 · checked 2026-09-29
3. bayl-r2-03 · randomized controlled trial in humans
   The largest decrease in cholesterol was in the LDL cholesterol with decreases of 32 to 40% after 30 days and decreases in all three groups were significant after only 20 days (Table 3).
   J Clin Biochem Nutr, 2009 · checked 2026-09-29
4. bayl-r2-05 · randomized controlled trial in humans
   A HFCM containing 6 g spice blend attenuated HFCM-induced postprandial IL-1β secretion in men with overweight/obesity.
   J Nutr, 2020 · checked 2026-09-29
5. bayl-r2-06 · EFSA scientific opinion
   Laurel leaf oil contains methyleugenol (3.1% on average, range: 2.3–4.0%), a compound with experimentally proven genotoxicity and carcinogenicity in rodents (IARC, 2018).
   EFSA Journal, 2023 · checked 2026-09-29
6. bayl-r2-04 · randomized controlled trial in humans
   Subjects continued their normal diets and their diabetic medications throughout the study. The subjects were taking sulfonylurea and metformin drugs. Subjects were not on statin drugs.
   J Clin Biochem Nutr, 2009 · checked 2026-09-29
7. hf2-bayl-1 · randomized controlled trial in humans
   Compliance was considered excellent as all capsules were consumed and subjects reported no significant side effects. Subjects continued their normal diets and their diabetic medications throughout the study. The subjects were taking sulfonylurea and metformin drugs. ... There were also no problems with compliance or problems associated with the consumption of 1 to 3 g of bay leaves per day.
   J Clin Biochem Nutr, 2009 · checked 2026-10-08
8. hf2-bayl-2 · agency guidance
   If you have diabetes, talk with your health care provider before taking a dietary supplement. Some supplements can interact with medicines, and some have been linked to kidney disease—a particular concern for people with diabetes because diabetes is the leading cause of kidney disease. ... Don’t take a dietary supplement instead of your diabetes medicine.
   NIH National Center for Complementary and Integrative Health, 5 Things To Know About Type 2 Diabetes and Dietary Supplements · checked 2026-10-08
9. bayl-r2-07 · EFSA scientific opinion
   Although individual consumption figures are not available, the Fenaroli's handbook of flavour ingredients (Burdock, 2009) cites values of 0.27 mg/kg bw per day for laurel (parts used: leaves and berries) (FEMA 2124), of 0.0029 mg/kg bw per day for laurel bay leaves extract (FEMA 2613) and 0.0027 mg/kg bw per day for laurel bay leaves oil (FEMA 2115).
   EFSA Journal, 2023 · checked 2026-09-29
10. bayl-r2-08 · animal study
    The dietary integration with dried bay leaves meal have resulted in a significant decrease in the blood lipid profile, glycemic profile and liver enzymes, with reduced levels of ALT and AST, glucose, total cholesterol, LDL cholesterol, triglycerides and increased HDL cholesterol.
    J Anim Physiol Anim Nutr (Berl), 2017 · checked 2026-09-29