Proanthocyanidins
Best for
Protect cholesterol from oxidation
Faint early signal · 400 mg/day for 12 weeks · 1 study , n=20
2 papers · 1 claim · 19 outcomes scored · 1 positive
Outcomes
What proanthocyanidins actually does, by outcome
Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.
Outcome Effect size Evidence Dose Weeks Rank
Protect cholesterol from oxidation Faint early signal
Keeps blood fats from becoming the oxidized particles that damage arteries.
1 RCT n=20 400 mg 12 wk #1/16
1 RCT
n=20
400 mg
12 wk
#1 /16
| Outcome | Effect | Evidence | Dose | Weeks | Rank |
|---|---|---|---|---|---|
| Protect cholesterol from oxidation Faint early signal | | 1 RCT n=20 | 400 mg | 12 wk | #1/16 |
Risk profile
Adverse events and known drug interactions
Safety events
dyspepsia
diarrhea
increased alanine aminotransferase (ALT)
decreased total cholesterol (TC)
increased hemoglobin
increased hematocrit
no adverse effect on histopathology
Sources
- 1. Effects of Grape Seed Proanthocyanidin Extract on Vascular Endothelial Function in Participants with Prehypertension: A Randomized, Double-Blind, Placebo-Controlled Study. (2019) ↑
- 2. Efficacy of Procyanidins against In Vivo Cellular Oxidative Damage: A Systematic Review and Meta-Analysis. (2015) ↑
Generated August 14, 2026
Related
More evidence for Proanthocyanidins
Ingredient evidence
Ingredient evidence
NewHydroxytyrosol
All scored outcomes
Aug 14, 2026
Ingredient evidence
Ingredient evidence
NewNiacin (vitamin B3)
All scored outcomes
Aug 14, 2026
Systematic review
Systematic review
NewGarlic for Cardiovascular Health: A Systematic Evidence Review
GRADE evidence review
Jun 7, 2026