tuneTypical Dose
240 mg daily of standardized bilberry extract was used in the 12-week visual-fatigue trial
Botanical
Bilberry
Vaccinium myrtillus
Evidence TierCWADA NOT PROHIBITED
watchEffect Window
Dry-eye improvements were assessed after 4 weeks, while visual-fatigue effects were clearer over 8 to 12 weeks.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Bilberry extract has limited but real human evidence for dry-eye symptoms and screen-related visual fatigue, but it is not a proven night-vision supplement.
Bilberry is often marketed as a general eye-health, night-vision, or metabolic supplement, but the best human evidence is much narrower. Small randomized trials support certain standardized extracts for dry-eye tear production and visual-display-related eye fatigue. Older night-vision claims do not hold up well in controlled trials, and newer cardiometabolic evidence is at most suggestive rather than confirmatory. Bilberry is better framed as a formulation-specific eye-comfort supplement than as a broad visual-performance or glucose-control enhancer.
Bilberry is usually framed around anthocyanin-rich extracts with possible effects on ocular microcirculation, oxidative stress, and visual-fatigue physiology. The human evidence supports only narrow formulation-specific eye-comfort outcomes, not a general visual-performance effect.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Modest support for dry-eye symptoms and tear production with a standardized extract
Secondary Outcomes
- Possible reduction in screen-related visual fatigue
- Evidence does not support night-vision enhancement claims
Safety
Contraindications and Interactions
Contraindications
- Planned use in place of eye-care evaluation for persistent visual symptoms
Side effects
- Mild GI upset
Interactions
- Anticoagulants or antiplatelet drugs
Avoid if
- You are expecting bilberry to fix impaired night vision or major eye disease
- You are relying on generic bilberry powders as equivalent to the studied standardized extracts
Evidence
Study-level References
bil-SRC-001Randomized controlled trial
Sourceopen_in_newBlando F, et al. The effect of a natural, standardized bilberry extract (Mirtoselect®) in dry eye: a randomized, double blinded, placebo-controlled trial. Minerva Oftalmol. 2017. PMID:28617532.
Population: Otherwise healthy adults with dry-eye symptoms.
Dose protocol: Standardized Mirtoselect bilberry extract daily for 4 weeks
Key findings: Improved Schirmer's test values and antioxidant-balance markers versus placebo in dry-eye symptoms.
Notes: Best direct dry-eye trial.
Paper content
This is the clearest bilberry dry-eye trial. A standardized extract improved objective tear production over 4 weeks, but the study was very small and used a proprietary product, so the finding should stay narrow.
bil-SRC-002Randomized controlled trial
Sourceopen_in_newKosehira M, et al. A 12-Week-Long Intake of Bilberry Extract (Vaccinium myrtillus L.) Improved Objective Findings of Ciliary Muscle Contraction of the Eye: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Trial. Nutrients. 2020. doi:10.3390/nu12030600. PMID:32106548.
Population: Healthy adult men and women aged 20 to 60 years performing visual-display and near-vision tasks.
Dose protocol: 240 mg standardized bilberry extract once daily for 12 weeks
Key findings: Improved objective markers of ciliary-muscle strain during visual-display tasks.
Notes: Best modern visual-fatigue trial.
Paper content
This is the strongest modern bilberry trial for screen-related visual fatigue. Over 12 weeks, 240 mg daily of standardized bilberry extract improved objective markers of ciliary-muscle strain during visual-display tasks.
bil-SRC-003Systematic review
Sourceopen_in_newCanter PH, Ernst E. Anthocyanosides of Vaccinium myrtillus (bilberry) for night vision--a systematic review of placebo-controlled trials. Surv Ophthalmol. 2004. doi:10.1016/j.survophthal.2003.10.006. PMID:14711439.
Population: Placebo-controlled clinical trials evaluating bilberry anthocyanosides for night-vision outcomes.
Dose protocol: Trial specific across placebo-controlled night-vision studies
Key findings: The better controlled night-vision studies were negative.
Notes: Important debunking review for the main marketing claim.
Paper content
This review is the key evidence anchor against bilberry night-vision marketing. The authors found that the best placebo-controlled evidence did not support a meaningful night-vision benefit, with the more recent rigorous trials producing negative results.
bil-SRC-004Randomized controlled trial
Sourceopen_in_newMcGraw PV, et al. The effect of bilberry nutritional supplementation on night visual acuity and contrast sensitivity. Altern Med Rev. 2000. PMID:10767671.
Population: Healthy young adults evaluated for night visual acuity and contrast sensitivity.
Dose protocol: 160 mg bilberry extract with 25 percent anthocyanosides
Key findings: No meaningful benefit for night visual acuity or contrast sensitivity in healthy adults.
Notes: Best direct negative night-vision RCT.
Paper content
This placebo-controlled trial is useful mainly because it undercuts the classic bilberry night-vision story. In healthy young adults, 160 mg bilberry extract did not meaningfully improve night visual acuity or contrast sensitivity.
bil-SRC-005Systematic review and meta-analysis of randomized controlled trials
Sourceopen_in_newTalebi S, Shirani M, Mahdavi A, Bagherniya M, Sahebkar A. Investigating the Effects of Vaccinium myrtillus Supplementation on Cardiometabolic Indices: A Systematic Review and Meta-Analysis. Phytother Res. 2025;39(9):4094-4115. doi:10.1002/ptr.70054. PMID:40751398.
Population: Adults receiving bilberry supplementation for at least 1 week across 11 RCTs (8 included in meta-analysis, total N=409).
Dose protocol: Various bilberry supplementation protocols across 8 RCTs (N=409)
Key findings: Near-significant HbA1c reduction (WMD -1.63%, P=0.06). No significant effects on fasting glucose, total cholesterol, HDL, triglycerides, or blood pressure.
Notes: First meta-analysis of bilberry cardiometabolic effects. Broadens the evidence picture beyond eye-health endpoints. Small total sample limits confidence.
Paper content
This systematic review and meta-analysis pooled 8 RCTs (N=409) examining bilberry supplementation effects on cardiometabolic indices. The analysis found a near-significant reduction in HbA1c (WMD -1.63%, P=0.06) but no significant effects on fasting glucose, total cholesterol, HDL, triglycerides, or blood pressure. An unexpected small unfavorable LDL signal (WMD +0.07 mmol/L, P=0.01) was observed. The authors concluded bilberry may have beneficial effects on HbA1c but the evidence for broader cardiometabolic benefit remains insufficient. Longer and higher-quality trials are needed.