Benefits
Body weight and waist size in overweight adults
In 88 overweight or obese women on the same reduced-calorie diet, adding 3 g a day of cumin powder in yogurt for 3 months was followed by more weight loss (about 6.2 versus 4.2 kg) and larger drops in waist size and fat mass than plain yogurt. Only the researchers were blinded. A placebo-controlled capsule trial reporting weight loss is under a journal expression of concern.
Blood cholesterol and triglyceride levels
In the same 88-woman diet trial, cumin powder lowered total cholesterol (about 26 versus 1 mg/dL), LDL and triglycerides and raised HDL slightly more than plain yogurt. Two meta-analyses of small trials, mostly from Iran, also found lower total cholesterol, with less consistent results for LDL and triglycerides. A 56-person cumin oil trial found no difference in blood fats.
Fasting blood sugar and insulin markers
In 90 adults with type 2 diabetes on oral medicines, 100 mg a day of cumin oil for 8 weeks lowered fasting glucose, HbA1c and insulin more than placebo, while 50 mg a day changed little; several values in that paper are hard to reconcile. A meta-analysis of 8 placebo-controlled trials found no significant change in fasting glucose, insulin or HOMA-IR.
Antioxidant enzyme and oxidative stress markers
In 56 adults with metabolic syndrome, 75 mg of cumin oil three times a day for 8 weeks raised the antioxidant enzyme superoxide dismutase and total antioxidant capacity, and lowered malondialdehyde, a marker of fat oxidation, compared with placebo. These are blood lab markers from a single trial, which found no change in weight, glucose or blood fats.
Return of bowel function after abdominal surgery
In 72 hospital patients analyzed after abdominal surgery in Iran, two 250 mg capsules of cumin seed extract given within hours of the operation were followed by earlier passing of gas (about 9 versus 12 hours) and an earlier first bowel movement (about 17 versus 26 hours) than placebo, with less bloating. This was one study in a hospital setting.
Digestive comfort: traditional use and one uncontrolled study
Cumin has a traditional use as a carminative for gas and bloating. In 57 Iranian adults with irritable bowel syndrome (50 analyzed), 20 drops a day of a cumin extract containing 2% essential oil for 4 weeks was followed by less abdominal pain and bloating, and symptoms partly returned after stopping. There was no placebo or control group, so natural change and expectation cannot be ruled out.
Reaction speed in healthy older adults
In a 12-week placebo-controlled study of 38 healthy adults aged 65 to 86 in Japan, one capsule a day supplying 25 mg of cuminaldehyde improved psychomotor speed and reaction time scores versus placebo, but not memory or the other test scores. The cumin group started with slower reaction times, and a spice company that employed three authors co-funded the study.
Mechanism of action
Cuminaldehyde and the essential oil
Most of cumin's aroma and much of its studied activity is attributed to cuminaldehyde, the main compound in the essential oil. Cumin seeds yield only a few percent of oil, so oil capsules are far more concentrated than the spice. Trial authors note that most earlier cumin research was in laboratory animals.
Proposed slowing of carbohydrate-handling enzymes (lab work)
In laboratory work cited by trial authors, cuminaldehyde inhibits the enzymes alpha-glucosidase, which helps break down carbohydrates in the gut, and aldose reductase. This is offered as a possible explanation for blood sugar findings; it was not measured in the human trials cited here.
Gut muscle relaxation (proposed)
Trial authors describe cumin as antispasmodic and anti-flatulent and propose that it blocks cholinergic receptors on gut smooth muscle. That is the usual explanation for its traditional use for gas and cramping. No human study cited here measured gut muscle activity directly.
Clinical trials
Randomized, double-blind, placebo-controlled 3-arm trial in Iran: Cuminum cyminum capsules, orlistat 120 mg or placebo, three times daily for 8 weeks; the abstract does not state the cumin dose. Reported results: weight -1.1 kg on cumin and -0.9 kg on orlistat versus +0.2 kg on placebo (P = 0.002), BMI -0.4 versus +0.1 (P = 0.003), and lower serum insulin on cumin than on orlistat or placebo (P = 0.02). (Taghizadeh et al. 2015, Ann Nutr Metab)
78 adults aged 18 to 60 (18 men, 60 women), 26 per group.
In 2023 the journal published an expression of concern citing discrepancies in group sizes and differences from the trial registration in participant demographics and start date. An Iranian national ethics committee is investigating, and the journal asks readers to interpret the data with caution until it concludes.
Randomized trial in Iran, single-blind (researchers, not participants): 3 g/day of cumin powder in low-fat yogurt at lunch and dinner for 3 months versus the same yogurt without cumin; both groups followed the same reduced-calorie diet and counseling. Per-protocol analysis: 100 enrolled, 88 analyzed; 3 women left the cumin group after developing a cumin allergy. Change in fasting glucose did not differ (P = 0.18). Registered IRCT2013021112429N1; no funding source or conflicts reported. (Zare et al. 2014, Complement Ther Clin Pract)
88 overweight or obese women aged 20 to 60 (analyzed).
Compared with plain yogurt, the cumin group lost more weight (6.2 versus 4.2 kg), BMI (2.35 versus 1.31 points), waist size (8.0 versus 5.9 cm) and fat mass (5.5 versus 3.8 kg), with no difference in fat-free mass. Total cholesterol fell by 26.5 versus 0.9 mg/dL and LDL by 9.6 versus 0.4 mg/dL; triglycerides fell more and HDL rose slightly more with cumin.
Randomized, double-blind, placebo-controlled trial in Urmia, Iran: cumin essential oil 100 mg/day, 50 mg/day or a paraffin placebo for 8 weeks, added to stable oral diabetes medicines. Capsules were made by Barij Essence, whose analysis listed thymoquinone and safranal (compounds typical of black seed and saffron) among the components. Several reported values, including HOMA-IR and QUICKI, are physiologically implausible, so the results need confirmation. No funding source stated; the authors declared no conflicts. (Jafari et al. 2017, J Tradit Complement Med)
99 adults with type 2 diabetes not using insulin, 33 per group; 90 analyzed.
The three groups differed significantly in fasting glucose, HbA1c, insulin, hsCRP and TNF-alpha. Almost all of the change was in the 100 mg group: fasting glucose fell by about 56 mg/dL, against changes of about 6 mg/dL or less in the other groups, and HbA1c from 7.09% to 5.31%. HOMA-B and QUICKI did not differ.
Randomized, triple-blind, placebo-controlled trial in Tabriz, Iran, in adults with metabolic syndrome: 75 mg cumin essential oil soft gels or placebo three times daily for 8 weeks, reported in two papers. The main paper found no between-group difference in weight, waist, blood glucose, insulin resistance, blood fats or systolic pressure; diastolic pressure ended 4.0 mmHg lower on cumin (81.4 versus 84.1 mmHg), although neither group changed significantly from baseline. (Morovati et al. 2019, Phytother Res)
56 adults aged 18 to 60 in Iran.
In the companion paper, cumin oil raised the antioxidant enzyme superoxide dismutase and total antioxidant capacity and lowered malondialdehyde, a marker of oxidative damage to fats, compared with placebo (P < 0.01). These are blood lab markers; the abstract's printed interval for malondialdehyde (-0.66 to 0.06) crosses zero despite the reported P value.
Double-blind, randomized, placebo-controlled trial in Iran: Barij Essence cumin capsules (stated to contain 25 mg saponin) or placebo three times daily before meals for 6 months. Changes in BMI, triglycerides, total cholesterol, LDL, ALT, fasting glucose and ultrasound fat grade did not differ from placebo; HDL rose more on cumin. No external funding was reported. (Shavakhi et al. 2015, Adv Biomed Res)
100 adults with biopsy-diagnosed nonalcoholic steatohepatitis; 81 completed.
The trial found no overall difference from placebo in the liver outcomes it measured, apart from a larger fall in the liver enzyme AST. Nausea was reported by 6 people on cumin and 2 on placebo and vomiting by 2 on cumin; overall side-effect rates were similar.
Triple-blind trial in Iran with allocation by minimization: two 250 mg capsules of ethanol extract of cumin seed, 4 and 5 hours after surgery, versus corn-starch placebo; funded by Rafsanjan University of Medical Sciences. (Amin et al. 2024, BMC Complement Med Ther)
74 adults undergoing abdominal surgery; 72 analyzed.
Mean time to passing gas was 9.0 hours on cumin versus 11.7 hours on placebo, and time to first bowel movement 17.0 versus 26.0 hours. Abdominal pain, bloating, nausea and vomiting in the first 24 hours were less frequent with cumin. This tested a short in-hospital use, not daily supplement use.