Benefits
Blood pressure support
Studied mostly as green coffee bean extract. A pooled analysis of 10 trials in 563 adults found systolic pressure about 3 mmHg and diastolic about 2 mmHg lower than on placebo, with larger effects in people with higher blood pressure and none seen in women. A trial in 28 adults with mild hypertension using 140 mg/day chlorogenic acid also lowered blood pressure.
Body weight and BMI in adults with overweight
Studied as green coffee bean extract. A pooled analysis of 3 small trials (103 adults, 1 to 8 weeks) using at least 500 mg/day chlorogenic acid found about 1.3 kg more weight loss than placebo. A larger pooled analysis of 16 trials found a small drop in BMI but no significant change in body weight or waist size; effects were larger when starting BMI was 25 or more.
Post-meal blood sugar response
In 15 overweight men, 1 g of chlorogenic acid lowered glucose and insulin 15 minutes into a glucose tolerance test, but not the total glucose response over 2 hours. In 30 adults with impaired glucose tolerance, 400 mg three times daily for 12 weeks lowered fasting glucose and raised an insulin sensitivity index within the chlorogenic acid group, with no change on placebo.
Mechanism of action
Glucose-6-phosphate transporter inhibition
In rat liver microsomes, chlorogenic acid blocked the transporter that carries glucose-6-phosphate into the enzyme system that releases glucose from the liver. Whether oral doses reach the liver at levels high enough to do this in people is not known.
Gut hormone and glucose absorption changes
In healthy volunteers, decaffeinated coffee rich in chlorogenic acid lowered the gut hormone GIP and raised GLP-1 after a glucose drink, a pattern consistent with slower glucose absorption in the intestine.
Colonic metabolism
In people without a colon, about 71% of the chlorogenic acids from a cup of coffee passed the small intestine unabsorbed. In people with an intact colon, gut bacteria convert them into compounds such as dihydroferulic and dihydrocaffeic acid that are absorbed and excreted in urine.
Clinical trials
Placebo-controlled, randomized trial of 140 mg/day chlorogenic acid from green coffee bean extract; the corresponding author worked for Kao Corporation. (Watanabe et al. 2006, Clin Exp Hypertens)
28 adults with mild hypertension.
Systolic and diastolic blood pressure fell significantly during the intake period in the chlorogenic acid group but not on placebo. BMI and pulse rate did not differ, and no apparent side effects were reported.
Systematic review and dose-response meta-analysis of randomized controlled trials. (Samavat et al. 2024, Diabetes Metab Syndr)
10 trials with 563 adults.
Green coffee bean extract lowered systolic pressure by 2.95 mmHg and diastolic by 2.15 mmHg versus control, with no effect on heart rate. Effects were larger in people with high blood pressure and absent in women, and no dose or duration relationship was found.
Systematic review and meta-analysis of randomized controlled trials of green coffee bean extract providing at least 500 mg/day chlorogenic acid, registered in PROSPERO. (Kanchanasurakit et al. 2023, Syst Rev)
3 trials with 103 adults, 1 to 8 weeks.
Body weight fell 1.30 kg more than on placebo (95% CI -2.07 to -0.52), with no heterogeneity. The authors noted the small sample and short trials and called for longer studies.
Systematic review and dose-response meta-analysis of randomized controlled trials of green coffee extract or chlorogenic acid. (Gorji et al. 2019, Phytomedicine)
16 trials reported in 13 articles, adults.
BMI fell slightly (by 0.40 kg/m2, p = 0.047), but body weight (by 0.59 kg, p = 0.21) and waist circumference (p = 0.07) did not change significantly. Trials in people with a starting BMI of 25 or more showed larger reductions, and supplementation under 4 weeks had no effect.
Randomized crossover trial of 12 g decaffeinated coffee, 1 g chlorogenic acid, 500 mg trigonelline or placebo before a 2-hour oral glucose tolerance test. (van Dijk et al. 2009, Diabetes Care)
15 overweight men.
Chlorogenic acid lowered glucose by 0.7 mmol/L and insulin by 73 pmol/L at 15 minutes compared with placebo, but did not change the total glucose or insulin response over 2 hours.