Benefits
Insulin and blood sugar markers in placebo-controlled trials
In adults with type 2 diabetes on medicine, 3 g/day for 10 weeks lowered HbA1c by 0.4 points and fasting insulin more than placebo. A 3-month trial in adults with liver fat also lowered insulin and HOMA-IR. A prediabetes trial and a tea trial found no blood sugar difference, and a pooled analysis of 6 trials found lower HOMA-IR and HbA1c but no change in fasting glucose or insulin.
Triglycerides and other blood lipids
With 3 g/day, one trial reported triglycerides 39.9 mg/dL lower than placebo after 10 weeks, and another a 35.7 mg/dL fall versus 9.7 mg/dL on placebo over 3 months. A pooled analysis of 12 trials found smaller drops in triglycerides and total cholesterol, while LDL and HDL did not change; a trial in women with prediabetes found no lipid difference from placebo.
Inflammation markers such as CRP, IL-6 and TNF-alpha
Compared with placebo, 3 g/day lowered hs-CRP in women with prediabetes after 8 weeks, and lowered hs-CRP, IL-6 and TNF-alpha in adults with liver fat after 3 months. Pooled analyses agree on CRP and IL-6, but a tea-based trial found no change, and these are blood markers rather than measures of how people feel.
Liver enzyme ALT and ultrasound liver fat grade
In one double-blind trial of 87 adults with overweight and liver fat on ultrasound, 3 g/day for 3 months lowered the liver enzyme ALT and improved the ultrasound fat grade more than placebo, while AST and body weight did not differ. The paper reports unusually narrow confidence intervals, and no independent group has repeated the result.
Blood pressure in controlled trials
In placebo-controlled trials in women with prediabetes and in a tea trial in adults with raised blood sugar, blood pressure did not differ from control. One pooled analysis reports drops of under 1 mmHg. An often-quoted Indian study of 20 adults found lower readings after 12 weeks, but it had no control group.
Body weight and waist size
A pooled analysis of 6 trials using 3 g/day for 8 weeks to 3 months found no effect on body weight, BMI or waist size. In a 16-week trial in women on a calorie-reduced diet, both groups lost weight and weight did not differ from placebo, though that trial's table reported a BMI difference that does not fit its weight data. Fat loss has been shown only in mice fed far larger amounts.
Mechanism of action
Aroma oil rich in 1,8-cineole and alpha-terpinyl acetate
Green cardamom oil is mostly oxygenated monoterpenes. In one lab comparison, 1,8-cineole was the main compound and alpha-terpinyl acetate made up about 29% of the green cardamom oil, while black cardamom oil had more geraniol. Proportions vary between samples.
Gut and blood-vessel tissue effects in lab studies
In animal tissue, a crude cardamom extract stimulated some gut tissue through a cholinergic route and relaxed other gut and blood-vessel tissue in a way that resembled calcium-channel blockers, and it lowered blood pressure in anesthetized rats. These are lab findings and have not been shown at food or supplement amounts in people.
SIRT1 and irisin as proposed signals
Two Iranian trials found higher blood SIRT1 and one found higher irisin with cardamom than placebo. The authors proposed these signaling proteins as links to the insulin and liver changes, but the trials measured them only in blood and did not test cause and effect.
Energy use in mice at high intakes
Mice fed diets containing 3% to 12% cardamom seed for 14 weeks burned more energy and stored less fat, with changes in brain appetite and hormone signals. The human equivalent of those intakes is many times the 3 g/day used in trials, where body weight did not change.
Clinical trials
Parallel, double-blind, randomized, placebo-controlled trial in Iran in adults with type 2 diabetes taking diabetes medicine; 3 g/day of green cardamom or rusk powder as placebo. Total, LDL and HDL cholesterol did not differ between groups. (Aghasi et al. 2019, J Sci Food Agric)
83 overweight or obese adults (41 cardamom, 42 placebo) given 3 g/day for 10 weeks.
Compared with placebo, the cardamom group had lower HbA1c (by 0.4 percentage points), fasting insulin, HOMA-IR insulin resistance and triglycerides (by 39.9 mg/dL), and higher SIRT1. The cholesterol fractions listed in the design did not differ.
Double-blind, randomized, placebo-controlled trial at the National Iranian Oil Company hospital in Tehran in adults with non-alcoholic fatty liver disease on ultrasound; funded by a Tehran University of Medical Sciences PhD grant; registered IRCT2015121317254N4. Weight, BMI, AST, fasting blood sugar and total cholesterol did not differ between groups. Both reports give confidence intervals that are unusually narrow for groups of about 43 people (for example, an insulin change of -2.7 with a 95% CI of -2.75 to -2.64, and an ALT change of -12.7 with a 95% CI of -13.6 to -11.7), so the precision of these results is uncertain. (Daneshi-Maskooni et al. 2018, Nutr Metab (Lond))
87 overweight or obese adults (43 cardamom, 44 placebo) taking two 500 mg capsules of whole green cardamom or toast flour three times a day with meals (3 g/day) for 3 months.
Compared with placebo, cardamom lowered hs-CRP, TNF-alpha, IL-6 and ALT, improved the ultrasound liver fat grade and raised SIRT1. The second report from the same trial found lower fasting insulin, HOMA-IR and triglycerides and higher HDL cholesterol, QUICKI and irisin; the LDL difference fell to a trend after adjustment. No side effects were reported in the cardamom group.
Randomized, double-blind, placebo-controlled trial in Tehran in women with prediabetes, raised blood lipids and overweight or obesity; funded by Tehran University of Medical Sciences; registered IRCT2014060817254N2. Blood pressure, blood sugar measures and blood lipids did not differ from placebo; the authors stated the effects on these were not different from placebo. (Kazemi et al. 2017, J Sci Food Agric)
80 overweight or obese women (40 per group) taking three 1 g capsules of whole green cardamom or rusk powder daily with meals for 2 months.
After covariate adjustment, cardamom lowered hs-CRP, the hs-CRP:IL-6 ratio and malondialdehyde compared with placebo; the abstract lists only these three markers as significant. The companion report on the same women found no between-group difference in the other outcomes listed in the design. Side effects in the cardamom group were diarrhea in 2 women, mild skin inflammation in 1 and a sore tongue (glossitis) in 1.
Double-blind, randomized, placebo-controlled trial in Kermanshah, Iran, in women with polycystic ovary syndrome and obesity; all followed a calorie-reduced diet; funded by Kermanshah University of Medical Sciences; registered IRCT20200608047697N1. The full-text table compares the groups only at the end of the study: fasting insulin (P = 0.001) and HOMA-IR (P = 0.025) were lower with cardamom, but HbA1c (P = 0.821), weight (P = 0.156) and waist (P = 0.366) did not differ, although the abstract describes improved glycemic indices. (Cheshmeh et al. 2022, Genes Nutr)
194 women who completed (99 cardamom, 95 starch placebo); dose given as 3 g/day of cardamom capsules in the abstract.
At the end, the full-text table shows lower androstenedione, DHEA and LH and higher FSH with cardamom than placebo, and both groups lost weight on the diet. Some of the table does not fit together: BMI and body fat differed between groups while weight and waist did not, and LH and ghrelin already differed at baseline. The methods describe the dose as three 1000 mg capsules three times a day, not the 3 g/day in the abstract, and the placebo as tablets.
Randomized controlled trial in Isfahan, Iran, in adults with type 2 diabetes; five groups drank three glasses of black tea daily with cardamom, cinnamon, ginger, saffron or nothing added. Blood sugar control, inflammation and oxidative stress markers, blood pressure and body measurements did not differ from tea alone. No blinding is described. (Azimi et al. 2014, Rev Diabet Stud)
204 adults across the five groups; the cardamom group took 3 g/day with tea.
The abstract reports significant effects on total, LDL and HDL cholesterol for the spice groups compared with tea alone, without giving separate figures for cardamom. The other outcomes in the design did not differ.
Systematic review and random-effects meta-analysis of randomized controlled trials searched to July 2023. (Zhang et al. 2024, Nutr Res)
989 adults in 12 trials.
Compared with control, cardamom lowered total cholesterol (by 8.56 mg/dL), triglycerides (by 14.09 mg/dL), hs-CRP and IL-6. HDL and LDL cholesterol and some oxidative stress indicators did not change significantly. The authors called for larger, better-designed trials.
Laboratory and animal work with a crude cardamom extract, including isolated guinea pig, rabbit and rat tissues and live rats and mice; the extract lowered blood pressure in anesthetized rats at 3 to 100 mg/kg. Not a human study. (Gilani et al. 2008, J Ethnopharmacol)
Animal tissues, rats and mice; no people.
The extract stimulated some gut tissue through a cholinergic route and relaxed other gut and blood-vessel tissue in a way that resembled calcium-channel blockers. It also increased urine output in rats and lengthened drug-induced sleep in mice. These are lab signals, not evidence of effects in people at food or supplement amounts.
Mouse feeding study with diets containing 3%, 6% or 12% cardamom seed; outcomes included fat mass, liver and muscle mitochondria and hormone signals. The authors' own conversion equals about 14.5 to 58.3 g of seed a day for a 60 kg adult. (Delgadillo-Puga et al. 2023, Int J Mol Sci)
Mice; no people.
Cardamom-fed mice gained less weight than controls despite eating slightly more, carried less fat and more lean mass, and burned more energy. The amounts were many times higher than the 3 g/day used in human trials, and human trials have not found a weight difference.