Chlorogenic acid (green coffee extract)
What it is
The main polyphenol in green (unroasted) coffee beans, substantially degraded during roasting — which is why brewed coffee is a weaker source. Inhibits glucose-6-phosphatase and slows intestinal glucose absorption. A 2024 meta-analysis of 9 randomised trials confirmed modest but statistically significant reductions in fasting glucose and post-prandial blood sugar at 400–600 mg/day over 8–12 weeks. Contains less caffeine than brewed coffee but is not caffeine-free. Generally well tolerated; high doses can cause GI upset and may mildly elevate homocysteine.
Dose
200–400 mg/day chlorogenic acid from green coffee extract (400–800 mg extract equivalent)
Time of day & tips
Take with or just before a meal to slow glucose absorption. Can be taken with water. Contains some caffeine — avoid in the evening if caffeine-sensitive.
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