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Blackcurrant (Ribes nigrum)
An anthocyanin-rich berry (Ribes nigrum) studied mainly for eye function and exercise blood flow. Small RCTs suggest it eases visual fatigue and increases ocular blood flow, and improves cycling performance/fat oxidation — but trials are small, single-product (CurraNZ), and some recovery endpoints came back null.
What the evidence says
Most Blackcurrant studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality randomised trials published 2000–2020 with a typical study size of 20 participants.
Based on 4 studies · 4 RCTs · 72 total participants
Confidence
ModerateBy outcome
Blackcurrant has an evidence score of 4/10 — emerging evidence based on 4 indexed studies. An anthocyanin-rich berry (Ribes nigrum) studied mainly for eye function and exercise blood flow. Small RCTs suggest it eases visual fatigue and increases ocular blood flow, and improves cycling performance/fat oxidation — but trials are small, single-product (CurraNZ), and some recovery endpoints came back null. Representative study: PMID 22377796.
The commonly studied dose of Blackcurrant is 300mg standardized NZ blackcurrant extract (~105mg anthocyanin) daily for exercise; ~50mg anthocyanins daily for visual outcomes. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
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Last reviewed June 2026 · evidence from 4 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Blackcurrant is exceptionally rich in anthocyanins (notably delphinidin and cyanidin glycosides), which underpin two distinct evidence streams. For vision: a double-blind crossover study found blackcurrant anthocyanosides dose-dependently lowered the dark-adaptation threshold and reduced VDT (screen)-induced visual fatigue at 50mg, and a 2-year RCT in open-angle glaucoma patients found slowed visual-field deterioration and increased ocular blood flow versus placebo (though no change in intraocular pressure). For exercise: standardized New Zealand blackcurrant extract (CurraNZ) increased peripheral blood flow, raised fat oxidation, and improved 16.1km cycling time-trial performance by ~2.4% in trained cyclists. The honest caveats are substantial: most trials are small (often <40 people), heavily reliant on a single commercial product, and results are not uniformly positive — a half-marathon recovery RCT found no effect on muscle-damage recovery, soreness, or fatigue. Blackcurrant is a promising but early-stage performance/eye supplement, not an established one.
Anthocyanins increase peripheral and ocular blood flow, proposed to aid substrate delivery during exercise and perfusion in the eye.
Standardized extract raises fat oxidation during moderate-intensity exercise in trained athletes.
Anthocyanins are proposed to support rhodopsin regeneration and reduce ciliary-muscle strain, lowering dark-adaptation threshold and screen-induced visual fatigue.
How Blackcurrant works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
300mg standardized NZ blackcurrant extract (~105mg anthocyanin) daily for exercise; ~50mg anthocyanins daily for visual outcomes
Can be taken without food
| Form | Type |
|---|---|
| 💊Standardized NZ blackcurrant extract (anthocyanin-standardized) | Recommended |
| 💊Blackcurrant anthocyanoside concentrate | Alternative |
Most trials used a single standardized commercial product; generic blackcurrant juice/jam is not equivalent.
Minimum: 1 weeks
Optimal: 8 weeks
Cycling: Not required
Note: For exercise, load ~7 days and take 1-2h pre-activity; for eye outcomes, take daily.
Dose-response data unavailable. The current published research for Blackcurrant does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Lower dark-adaptation threshold and reduced screen-induced visual fatigue at ~50mg anthocyanins.
~2.4% faster 16.1km time-trial and higher fat oxidation in trained cyclists after 7 days.
A 2-year glaucoma RCT found increased ocular blood flow and slowed visual-field deterioration (no IOP change).
A half-marathon RCT found no effect on muscle-damage recovery, soreness, or fatigue — benefits are not universal.
May be a useful adjunct alongside (not a replacement for) prescribed antiglaucoma therapy; discuss with an ophthalmologist.
Dietary amounts are fine; standardized supplemental extracts are not specifically studied — consult a clinician.
Anthocyanins may have mild effects on platelet aggregation/blood flow; generally benign but worth noting with blood thinners.
Tip: Take with food; reduce dose
Both are anthocyanin-rich berries traditionally studied for visual function and ocular blood flow.
Layered anthocyanin support for eye/visual outcomes.
Macular carotenoids complement blackcurrant anthocyanins through a different visual-protection pathway.
Broader eye-health coverage (macular pigment plus blood flow / visual fatigue).
Timing is flexible for Blackcurrant — consistent daily use matters more than the time of day. For exercise, load for ~7 days; can be taken 1-2 hours before activity.
Blackcurrant is generally well-tolerated and considered safe for most healthy adults at recommended doses. The most commonly reported side effects are mild GI upset. Use caution if any of these apply to you: No major contraindications at dietary/supplemental doses.
Andean root that boosts energy and libido through hormonal signaling modulation — different colors (red, black, yellow) have distinct effects.
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