Raspberry Ketones
Compounds found naturally in raspberries (in very small amounts), synthesised for supplements. Heavily promoted after being featured on popular TV health programmes. There is essentially no human clinical trial evidence that raspberry ketones cause weight loss. The evidence base consists almost entirely of animal studies — which have not translated to humans.
Quick read · 3 min
- •Evidence: Very weak — little to no reliable trial evidence
- •There are no published randomised controlled trials evaluating raspberry ketones alone for weight loss in humans.
- •Insufficient human trial data to fully assess safety.
- •Prescription weight loss drugs produce 7–21% weight loss in trials. Most supplements in this category produce less than 2 kg.
Based on clinical trials · No rankings · Every claim linked to source
Last reviewed: March 2026
How it works
In rodent studies, raspberry ketones increased the breakdown of fat cells and raised levels of adiponectin (a hormone involved in metabolism). These findings in animals generated significant media interest. The problem: no rigorous randomised controlled trials in humans have tested raspberry ketones alone for weight loss, so we have no reliable evidence these mechanisms work the same way in people.
What the evidence shows
There are no published randomised controlled trials evaluating raspberry ketones alone for weight loss in humans. The evidence base consists of animal studies and one short-term human study that combined raspberry ketones with multiple other substances (caffeine, capsaicin, garlic, and ginger) — making it impossible to know which ingredient, if any, was responsible for any effect. The NIH and FDA do not consider raspberry ketones to be an effective weight loss supplement based on available human evidence.
Safety
Insufficient human trial data to fully assess safety. Raspberry ketones are often sold in combined 'fat burner' formulas alongside caffeine and other stimulants — the combination products may cause stimulant-related side effects (insomnia, rapid heart rate, anxiety). The raspberry ketone component itself has not been adequately studied for safety in humans at supplement doses.
Community insights
These are personal experiences shared in public online communities — not medical advice.
“This is probably the single most overhyped supplement on the market. It became popular from TV promotion, not from any clinical evidence in humans. Save your money.”
“The studies that get cited are all in mice. Mouse fat cells responding to something does not mean it works in humans — this is a fundamental point about research translation.”
Common questions
After reading this page, most people compare this with other supplements, look at prescription options, or check what they can do today without a prescription.