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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.

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.

Scientific references

Where to buy

Vitacost, Raspberry Ketones, 300 mg, 60 Capsules

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