Compound or practice · Supplement

Cocoa Flavanols

The flavanols in cocoa genuinely improve blood-vessel function and modestly lower blood pressure — the sugar is the catch.

Overall grade: Grade B
Last revised: Jul 10, 2026; 3
graded outcomes: 0
references listed

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A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.

3 at grade B · 1 at grade C — 4 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
Endothelial functionFlow-mediated dilation	Evidence grade B	Moderate	high
Blood pressureModest reduction	Evidence grade B	Small	high
Cognition / brain blood flowEmerging	Evidence grade C	Small	mixed

Endothelial functionEvidence grade B
Flow-mediated dilation
Moderatehigh
Blood pressureEvidence grade B
Modest reduction
Smallhigh
Cognition / brain blood flowEvidence grade C
Emerging
Smallmixed

Conditions

How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.

Hypertension May improveEvidence grade BModestGrade B

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: Cognition / brain blood flow (grade C).
Caution with Blood-pressure medications: Additive blood-pressure lowering.

Interactions

Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.

Blood-pressure medicationsCaution
Additive blood-pressure lowering.

The evidence in words

What it is

Cocoa flavanols are polyphenols in cocoa (and dark chocolate) studied for vascular and cognitive health.

How it works

They boost nitric-oxide-mediated vasodilation, improving endothelial function and blood flow, including to the brain.

What the evidence shows

Meta-analyses support improved flow-mediated dilation and small blood-pressure reductions; the large COSMOS trial hinted at cardiovascular-mortality benefit from cocoa-flavanol supplements. Cognitive signals exist. Chocolate's sugar and calories offset the benefit — flavanol content, not cocoa taste, is what matters.

How to use it

~500 mg cocoa flavanols/day from a standardized supplement or high-flavanol cocoa; dark chocolate is a weak, sugary source.

Safety & interactions

Safe; watch caffeine/theobromine and the sugar in chocolate. antihypertensives — Additive blood-pressure lowering.

Bottom line

A real vascular benefit from cocoa flavanols — but get them from a standardized source, not a candy bar. ~500 mg/day.

How it is used

As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.

Standard: ~500 mg cocoa flavanols/day, standardized.

Entries that share this one's tags or conditions.

Cocoa Flavanols for Blood pressureEvidence grade B — Modest reductionEvidence grade B
Cocoa Flavanols for Cognition / brain blood flowEvidence grade C — EmergingEvidence grade C
Cocoa Flavanols for Endothelial functionEvidence grade B — Flow-mediated dilationEvidence grade B
Cocoa Flavanols for HypertensionEvidence grade B — ModestEvidence grade B

Sources

This entry lists no references of its own.

Last revised Jul 10, 2026. A grade is this entry's reading of the evidence, not medical advice.