MKP

Three human trials exist and they point in different directions.

Blood pressure. A 12-week trial in adults with high-normal pressure or grade 1 hypertension found systolic pressure of 123.0 against 128.1 mmHg and diastolic 77.4 against 80.1, both significant, with a between-group change of about 4.9 mmHg systolic and 2.9 diastolic ^[3]. ⚠️ Two caveats: the analysis was per-protocol after 18 post-hoc exclusions for low compliance, and the trial enrolled 121 against a plan for 200.

Cognition. A 24-week trial in 268 older adults at 200 micrograms daily MISSED its primary endpoint; the assumed effect size was 0.40 and the observed one was 0.12 ^[4]. One of eleven subscales, orientation, reached p equals 0.022 with no correction for multiple comparisons, and the baseline population scored near the ceiling of the test. Every subgroup finding had a non-significant interaction term.

⚠️ Provenance is the limitation that outweighs the others. The discovery paper, the enzyme kinetics, the rat studies, all three human trials and the absorption work originate from Morinaga Milk Industry. No finding has been replicated by an independent laboratory. A further blood-pressure trial cited throughout the company's own literature is not indexed in PubMed and could not be verified.

The safety record is reassuring as far as it goes. A dedicated tolerance trial gave 30 people 1,000 micrograms daily for four weeks, ten times the usual blood-pressure dose, and found no abnormality in body measurements, blood pressure, blood chemistry or urine, with no adverse events attributed to the peptide ^[5]. The larger trials reported hundreds of adverse events across both arms, all mild and transient, none attributed ^[3][4].

This is a fragment of a common food protein, consumed in milk products throughout life, so the baseline expectation of harm is low. The obvious caution is pharmacological rather than toxicological: it inhibits the same enzyme as ACE-inhibitor drugs, so anyone already taking an ACE inhibitor, an angiotensin receptor blocker or another blood-pressure medicine should treat it as additive rather than separate.

⚠️ All safety data comes from the same corporate source as the efficacy data.

Milk-derived peptides that inhibit angiotensin-converting enzyme have been studied since the 1980s, and two of them, the lactotripeptides valine-proline-proline and isoleucine-proline-proline, became the basis of functional foods sold widely in Japan and Europe for blood pressure. MKP was isolated at Morinaga Milk Industry from a casein hydrolysate and reported in 2013 as an unusually potent member of the same family, contributing a third of its parent hydrolysate's activity from a twentieth of a percent of its mass. The company then took it in two directions: blood pressure, where the pharmacology is straightforward, and cognition, where the rationale rested on a blood-brain-barrier claim that the tracer experiment does not support. The blood-pressure programme produced a positive if modest trial; the cognition programme produced one that missed its endpoint.