Supplement analysis backed by scientific evidence · PT

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Limited evidenceHeart & metabolic

Bonito Peptides

ACE-inhibiting peptides from dried bonito fish, sold for blood pressure. The mechanism is well characterised but the human trials are few, small and decades old.

Evidence last reviewed: August 2026

What the science says

  • ACE inhibition is the documented mechanism Moderate evidence

    The bonito-derived peptide LKPNM was characterised as a prodrug-type ACE inhibitor: digestion releases a more potent fragment. This is biochemical evidence, not clinical proof of benefit.

  • Small blood pressure reductions in fish peptide trials Limited evidence

    A randomised trial of a related sardine-derived peptide reported systolic reductions of a few mmHg in mildly hypertensive people. Trials of bonito peptides themselves are sparse and mostly predate modern reporting standards.

  • Reviews rate the clinical evidence as immature Limited evidence

    Reviews of animal-derived antihypertensive peptides conclude that in vitro ACE inhibition translates inconsistently into measurable human blood pressure effects.

Dosage & safety

Studied doseProducts typically supply 1.5–3 g/day of bonito peptide hydrolysate; the trial literature used comparable amounts of fish peptide preparations over 4–8 weeks.
SafetyFish-derived, so avoid with fish allergy. Mild GI upset and a fishy aftertaste are common. May add to prescription antihypertensives; monitor if you take an ACE inhibitor or ARB.

Scientific references

Where to buy

View on iHerb

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