Limited evidenceWeight management

Raspberry Ketones

There is no published randomised trial of raspberry ketone as a single ingredient in humans — none. The entire commercial case rests on rodent and cell studies using doses roughly a hundred times higher than any supplement provides, plus one trial of an eight-ingredient stimulant blend.

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What the science says

No human evidence for raspberry ketone alone Limited evidence
No randomised controlled trial has tested raspberry ketone as an isolated ingredient for weight loss in humans. Systematic reviews of weight-loss supplements repeatedly list it among compounds with insufficient evidence to evaluate. Here the absence of evidence is close to complete, not merely thin.
The one cited human trial tested a blend, not the ketone Limited evidence
The study routinely used to support raspberry ketone tested METABO, a multi-ingredient product also containing caffeine, capsaicin, bitter orange (synephrine), garlic and ginger, in 45 adults on a diet and exercise programme for 8 weeks. Body weight fell 2.0% versus 0.5% on placebo and fat mass 7.8% versus 2.8%. Nothing in that design allows any of it to be attributed to raspberry ketone.
Animal doses are unreachable in humans Limited evidence
Rodent studies showing increased lipolysis, raised adiponectin and resistance to diet-induced weight gain typically fed raspberry ketone at 1-2% of the diet, roughly 100-200 mg/kg body weight — the equivalent of many grams per day in a human, versus the 100-500 mg typically supplied by supplements.
Product quality is poor Limited evidence
Analytical work on commercial raspberry ketone supplements found frequent adulteration, including synthetic raspberry ketone sold as naturally derived, and label content that did not match analysis. Natural raspberry ketone is one of the most expensive natural flavour compounds in existence, so cheap "natural" products are essentially always synthetic.

Dosage & safety

Studied doseNo effective human dose has been established. Commercial products typically supply 100-500 mg/day, a dose that has never been shown to do anything in a human trial. We cannot recommend a dose because there is nothing to base one on.

SafetyHuman safety data are essentially absent beyond long-standing use as a food flavouring at tiny doses. Raspberry ketone is structurally related to synephrine and other phenolic amines, raising a theoretical concern about cardiovascular stimulation at high doses, and rodent work has reported adverse behavioural and metabolic effects at large intakes. In the EU it is approved as a flavouring substance rather than assessed for high-dose supplement use, and several regulators have flagged concentrated supplement products as falling outside that assessment. Products are frequently sold in stimulant blends whose other ingredients carry the real risk. Avoid in pregnancy and breastfeeding, in cardiovascular disease, and alongside other stimulants.

How to take it

TimingTiming does not matter — no dose or schedule has been shown to do anything in a human trial.

With food?With or without food.

Worth knowingRead the whole ingredient list: raspberry ketone is almost always sold in a stimulant blend, and the other ingredients carry the real risk.

Frequently asked questions

Do raspberry ketones work for weight loss?

There is no evidence that raspberry ketones work: no randomised trial has tested raspberry ketone alone for weight loss in humans. The case rests on rodent studies at doses roughly a hundred times higher than supplements supply, plus one trial of an eight-ingredient stimulant blend.

How much raspberry ketone should I take?

No effective human dose of raspberry ketone exists. Products typically supply 100-500 mg/day, a dose never shown to do anything in a human trial.

Are raspberry ketones safe?

Human safety data for raspberry ketone supplements are essentially absent beyond tiny doses as a food flavouring. Raspberry ketones are usually sold in stimulant blends whose other ingredients carry the real risk, so avoid them in pregnancy, cardiovascular disease and alongside other stimulants.

Are 'natural' raspberry ketone supplements really natural?

Almost never — natural raspberry ketone is one of the most expensive flavour compounds, so cheap 'natural' products are essentially always synthetic. Analyses of raspberry ketone supplements have found frequent adulteration and labels that did not match contents.

Scientific references

Eight weeks of supplementation with a multi-ingredient weight loss product enhances body composition, reduces hip and waist girth, and increases energy levels in overweight men and women
Lopez HL, Ziegenfuss TN, Hofheins JE, et al. — J Int Soc Sports Nutr, 2013
Evaluation of quality and authenticity of raspberry ketone supplements by a multianalytical approach
Luque-Jurado I, Yesares M, Soria AC, et al. — J Chromatogr A, 2025

Where to buy

Vitacost, Raspberry Ketones, 300 mg, 60 Capsules

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