Green Coffee Bean Extract and PCOS: We Spill the Beans

After Dr. Oz promoted its “magic” weight loss benefits on his show, millions of Americans were introduced to green coffee bean extract. And chances are, you’ve seen the ads, contests and promotions for green coffee bean extract targeting women with PCOS. We’ve received numerous requests from women asking us for our advice regarding the use of green coffee bean extract for helping with symptoms of PCOS, especially, if it causes weight loss. In this post, we spill the beans by examining the scientific evidence of green coffee bean extract for the management of PCOS.

What Is It?

Green coffee bean extract, a potential antioxidant has high concentrations of polyphenols called chlorogenic acids (also present in roasted coffee and black tea). Chologenic acids influence glucose metabolism by inhibiting the enzyme glucose-6-phosphatase, which plays a role in the liver’s glucose production. Besides weight loss and improvements in glucose, green coffee bean extract is also associated with minimizing blood pressure spikes.

The Evidence

Only a few human studies that use cholorgenic acid exist (none that examine the use in women with PCOS) and most had small sample sizes and poor design.

In the most recent study published in 2012 in Diabetes, Metabolic Syndrome and Obesity, overweight individuals from India were randomly assigned to a high-dose of cholorgenic acid, a low-dose of it, and a placebo for 6 weeks at a time, separated by a 2-week washout period. The chlorogenic acid content was 45.9% and the dosage ranged from 700 to 1050 mg. No changes to diet were made. Significant reductions in body weight (an average of 10% loss), BMI, and percent body fat were found.

Many, however, question the validity of this study as it was funded by a supplement manufacturer & not registered at It had a tiny sample size (only 16 adults), lacked proper blinding and doses, had unreliable diet recalls and repeated measurements. There was no mention of the results of those taking higher dosages of chlorgenic acid versus lower dosages. An article from Science-based Medicine summarizes the problems with this study well.

Another randomized control trial published in Nutrition and Metabolism studied the effects of 12 g decaffeinated coffee, 1 g chlorogenic acid, and placebo on glucose levels in 15 overweight men. No changes in glucose or insulin secretion were found.

There is some evidence, again from small sample sizes, that cholorgenic acid may lower blood pressure but more long-term and large sample sizes are needed.

Side Effects

Chlorogenic acid has been shown to raise total homocysteine concentrations in coffee and tea drinkers. (Elevated homocysteine levels is a risk factor for heart disease). Since cholorgenic acid may play a role in glucose metabolism, it could cause low blood sugar. It may also cause nutritional malabsorption issues and should not be used is you are pregnant or breastfeeding.

Bottom Line

Don’t believe the hype or clever marketing. There is no “magic pill” for weight loss– especially one that claims weight loss without lifestyle changes. If there were, pharmaceutical companies wouldn’t be investing billions of dollars to find one.

Until more long-term and well controlled studies examining the use of green coffee bean extract in PCOS are done, we won’t be recommending it. Your money can be better well spent on dietary supplements that do have substantial and reliable evidence to improve reproductive and metabolic symptoms of PCOS such as n-acetyl cysteine (NAC) and myo-inositol and d-chiro inositol.


  • Vinson JA et al. Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects.Diabetes Metab Syndr Obes. 2012;5:21-7.
  • Olthof MR et al. Acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on incretin hormones. Nutr Metab (Lond). 2011 Feb 7;8:10.
  • Olthof MR, Hollman PC, Zock PL, Katan MB.Consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans.Am J Clin Nutr. 2001 Mar;73(3):5328.
  • Watanabe T, Arai Y, Mitsui Y, Kusaura T, Okawa W, Kajihara Y, Saito I.The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension. Clin Exp Hypertens. 2006 Jul;28(5):439-49.
  • Kozuma K, Tsuchiya S, Kohori J, Hase T, Tokimitsu I.Antihypertensive effect of green coffee bean extract on mildly hypertensive subjects. Hypertens Res. 2005 Sep;28(9):711-8.
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