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Bilberry appears to help in 14 of 16 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2004–2026 with a typical study size of 31 participants.
Based on 39 studies · 2 meta-analyses · 33 RCTs · 2,539 total participants
Confidence
High
What the studies found
14helped2unclear· 23 more without graded effect data
By outcome
Glucose & metabolic
Likely helps10 studies
Vision & eye healthReduced eye fatigue and improved visual comfort within 4-8 weeks · 4-8 weeks
Likely helps9 studies
InflammationAnthocyanins provide antioxidant and anti-inflammatory support · 4-8 weeks
Likely helps9 studies
Heart & blood pressureAnthocyanins support vascular health and circulation · 8-12 weeks
Likely helps8 studies
Cholesterol & lipidsAnthocyanins support vascular health and circulation · 8-12 weeks
Mostly mechanism / observational6 studies
Weight management
Likely helps5 studies
Therapeutic & clinical
Mostly mechanism / observational3 studies
Safety profile
Mostly mechanism / observational3 studies
Liver health
Too few graded studies2 studies
Digestive health
Too few graded studies2 studies
Recovery
Too few graded studies2 studies
Skin health
Too few graded studies1 study
By the numbers
Pulled from 31 studies with measurable effects
Likely real effects
77%
across studies
People studied
2,539
typical study: 31 people
Strongest designs
35
2 pooled, 33 randomised
Showed benefit
88%
14/16 studies
How long studies ran
1–4 weeks
2
1–3 months
7
3+ months
2
Populations Studied
General population7
Healthy individuals1
Patients with diabetic retinopathy1
Intermediate AMD patients1
Steady research
11 studies in the last 5 years · Latest meta-analysis: 2025
200420152026
1Fasting blood glucoseMeta-Analysisn=409 · medium study2025
Therefore, long-term and high-quality trials are needed to confirm the promising effects of bilberries.
Talebi S et al. · Phytotherapy research : PTR (2025)
No clear effect
← WorseNo effectBetter →
Could be chance
Mean changes and their SDs were used to calculate overall effect sizes, with the Hozo et al. method converting SEs, 95% CIs, and IQRs to SDs.
Combining five effect sizes from the five trials on long-term effects of bilberry administration compared with controls resulted in a non-significant decrease in FBG (WMD: -0.08 mmol/L, 95% CI: -0.22 to 0.07, p = 0.30).
For HbA1c, the meta-analysis of three RCTs showed a marginally significant reduction (WMD: -1.63%, 95% CI: -3.36% to 0.11%, p = 0.06).
2Systematic ReviewCited 15×n=20 · very small study2021
In conclusion, bilberry and blackcurrant extract appears effective in lowering HbA1c and total and LDL cholesterol, whereas grape seed extract may lower total and LDL cholesterol, and blood pressure, in specific population groups.
Grohmann T et al. · Nutrients (2021)
Intervention with grape seed extract may reduce systolic and diastolic blood pressure in subjects with hypertension or metabolic syndrome.
Differential responsiveness in cholesterol and blood pressure outcomes between stratified populations could not be explained by age, dose or study duration.
In conclusion, bilberry and blackcurrant extract appears effective in lowering HbA1c and total and LDL cholesterol, whereas grape seed extract may lower total and LDL cholesterol, and blood pressure, in specific population groups.
3Antiaging effects of bilberry compoundsSystematic Review2026
This review offers a summary of the existing information on the antiaging potential of bilberry fruits and leaves, and analytically reviews the outcome of clinical trials, with special attention towards its medicinal properties.
Patra JK et al. · Nutrients (2026)
It is also stated to promote antioxidant defense and lower oxidative stress, having antiaging, anti-inflammatory, lipid-lowering, antimicrobial effects, lowering blood glucose and other age-related diseases, etc.
Reports suggest that apart from the fruit, the leaves of bilberry are equally rich in numerous bioactive compounds of medicinal importance.
This current review offers valuable insights on bilberry fruits, leaves, and extracts, providing an inclusive assessment of their bioactive compound configuration, related biological prospects, and the extraction methodology of their major compounds.
An evidence-based systematic review including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.
Ulbricht C et al. · Journal of dietary supplements (2009)
An evidence-based systematic review including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.
Our findings demonstrate the efficacy of FBE in improving skin aging and complexion evenness.
Nobile V et al. · Nutrients (2024)
Noticeable benefit
← WorseNo effectBetter →
At D84, the wrinkle depth had decreased by 10.6%, Ra had improved by 7.9%, Rz had decreased by 7.3%, R0 had improved by 13.3%, R2 had improved by 12.4%, and skin antioxidant capacity had increased by 20.8%.
ITA° increased by 20.8% and was accompanied by a decrease in the skin's redness component by 16.8% and an increase in the lightness component by 2.2%.
The variation of all the above-mentioned parameters was statistically significant between the FBE and PL groups.
8High-frequency component (HFC)-1 valueRCTCited 20×n=109 · medium study2020
This study shows that oral consumption of 240 mg SBE extract for 12 weeks relieves the tonic accommodation of the ciliary muscle caused by VDT tasks and near-vision tasks.
Kosehira M et al. · Nutrients (2020)
Likely real
Results showed that post-load HFC-1 values at weeks 8 and 12 were significantly improved in the SBE group than in the placebo group (p = 0.014 and 0.017, respectively).
Regarding the difference between before and after the task load (ΔHFC-1), the values were significantly better in the SBE group than in the placebo group at week 4 and 12 (p = 0.018 and 0.049, respectively).
Tests were performed before and after VDT tasks at week 0, 4, 8, and 12; high-frequency component (HFC)-1 value was the evaluation outcome.
10Macular pre-ganglionic element function in intermediate AMDRCTCited 21×n=30 · small study2019
In intermediate AMD, Macuprev® supplementation increases the function of the macular pre-ganglionic elements, with no associated retinal and choroidal ultra-structural changes.
Parravano M et al. · Advances in therapy (2019)
In intermediate AMD, Macuprev® supplementation increases the function of the macular pre-ganglionic elements, with no associated retinal and choroidal ultra-structural changes.
11Plasma alanine aminotransferaseRCTCited 91×n=74 · small study2015
Further studies are warranted to determine the clinical applications of anthocyanin in NAFLD.This trial was registered at clinicaltrials.gov as NCT01940263.
Zhang PW et al. · Medicine (2015)
Large benefit
← WorseNo effectBetter →
Borderline
Compared to controls, the anthocyanin group exhibited significant decreases (P < 0.05, all comparisons) in plasma alanine aminotransferase (-19.1% vs 3.1%), cytokeratin-18 M30 fragment (-8.8% vs 5.6%) and myeloperoxidase (-75.0% vs -44.8%).
Significant decreases from baseline in fasting blood glucose and homeostasis model assessment for insulin resistance were observed in the anthocyanin group; however, these differences were not significant relative to placebo controls.
Further studies are warranted to determine the clinical applications of anthocyanin in NAFLD.This trial was registered at clinicaltrials.gov as NCT01940263.
12Near visual acuity improvementRCTCited 8×n=23 · very small study2024
Preliminary studies show an improvement in near visual acuity and conjunctival hydration on the Schirmer test, but this needs to be confirmed in further studies.
Szumny D et al. · Nutrients (2024)
Huge benefit
← WorseNo effectBetter →
Only in the next cycle of the study was an improvement in near visual acuity observed in 92.3% of the patients.
On the other hand, an improvement in conjunctival wetting was observed in the Schirmer test at the beginning of week 6 of administration in 80% of patients.
This effect was weakened in subsequent weeks of conducting the experiment to 61.5%.
13Urine total phenolicsRCTCited 19×n=103 · medium study2017
This randomized clinical trial of overweight/obese women showed that 12 weeks ingestion of a mixed flavonoid nutrient supplement was associated with a corresponding increase in urine total phenolics and gut-derived phenolic metabolites.
Nieman DC et al. · Journal of proteome research (2017)
Large benefit
← WorseNo effectBetter →
Likely real
At 4 weeks, urine total phenolics increased 24% in F versus P with similar changes at 12 weeks (interaction effect, P = 0.041).
Metabolomics data indicated shifts in 63 biochemicals in F versus P with 70% from the lipid and xenobiotics superpathways.
The largest fold changes in F were measured for three gut-derived phenolics including 3-methoxycatechol sulfate, 3-(3-hydroxyphenyl)propanoic acid sulfate, and 1,2,3-benzenetriol sulfate (interaction effects, p ≤ 0.050).
Majeed M et al. · Journal of medicinal food (2021)
Huge benefit
← WorseNo effectBetter →
Borderline
In the case of objective symptoms, only 40% of the subjects (P < .05) had abnormal Amsler's grid aberration scores on day 90 compared with 77.5% of subjects at the beginning of the study.
No adverse events were observed during the study.
This pilot study provides evidence that Macumax® supplementation is safe and maintained eye health without further progression of the disease in patients with early-stage dry-type AMD.
This short-term study of bilberry supplementation did not show significant effects on cardiovascular risk factors or antioxidant status, but the tendency for improved glycemic control may suggest a longer treatment period may be effective in diabetic patients.
Chan SW et al. · Phytotherapy research : PTR (2021)
Noticeable benefit
← WorseNo effectBetter →
HbA1c was reduced by 0.31 ± 0.58% during bilberry supplementation, but this change was not significantly different from that with placebo.
Results showed no effect on body weight, blood pressure, or lipid profile.
Antioxidant status, oxidative stress, and inflammatory status showed no significant differences across treatments.
These data do not support the notion that regular consumption of anthocyanins beneficially affects glycemic control or lipoprotein profiles or functions.
Aboufarrag H et al. · Molecular nutrition & food research (2022)
These data do not support the notion that regular consumption of anthocyanins beneficially affects glycemic control or lipoprotein profiles or functions.
It is possible the no effect observation is due to the relatively short duration of treatments.
17Potential exposure markers discoveryRCTCited 3×n=20 · very small study2022
Renai L et al. · Analytical and bioanalytical chemistry (2022)
The correct selection of statistically significant PEMs is a crucial analytical step for understanding nutrition-health interactions.
Principal component analysis and sample classification through linear discriminant analysis performed on PEM maximum intensity confirmed the discriminating role of these PEMs.
18Fasting serum hippuric acid levelsRCTCited 60×n=47 · small study2017
Fasting serum hippuric acid is increased after consumption of anthocyanin-rich bilberries, and may contribute to the beneficial effect of bilberry consumption through its associations with better glycemic control and β-cell function.
de Mello VD et al. · Molecular nutrition & food research (2017)
Noticeable benefit
← WorseNo effectBetter →
Likely real
Fasting serum hippuric acid increased significantly (3.5-fold, p = 0.001) only in the BB group and correlated with changes in fasting plasma glucose concentration (r = -0.54, p < 0.05) and insulin secretion (r = 0.59, p < 0.05).
Fasting serum hippuric acid is increased after consumption of anthocyanin-rich bilberries, and may contribute to the beneficial effect of bilberry consumption through its associations with better glycemic control and β-cell function.
It appears that berry intake has an ameliorating effect on some markers of gingival inflammation reducing gingivitis to a similar extent compared to standard of care.
Widén C et al. · International journal of molecular sciences (2015)
Huge benefit
← WorseNo effectBetter →
The mean reduction in BOP before and after consumption of test product over 1 week was 41% and 59% in the groups that consumed either 250 or 500 g of bilberries/day respectively, and was 31% in the placebo group, and 58% in the standard of care reference group.
The analysis only showed a significant reduction in cytokine levels in the group that consumed 500 g of bilberries/day.
A statistically significant reduction was observed for IL-1b (p=0.025), IL-6 (p=0.012) and VEGF (p=0.017) in GCF samples in the group that consumed 500 g of bilberries daily.
Since potatoes are the world's largest non-grain commodity, replacing yellow-fleshed potatoes with purple-fleshed potatoes as staple food could have large potential in maintaining public health.
Linderborg KM et al. · International journal of food sciences and nutrition (2015)
Noticeable benefit
← WorseNo effectBetter →
Likely real
The purple potato meal caused smaller insulinemia than the yellow potato meal (iAUC 120 min 1347 and 2226, respectively, p = 0.012 and iAUC 240 min 1448 and 2403, p = 0.007) or the bilberry meal (iAUC 120 min 1920, p = 0.027).
The purple potato meal caused a smaller plasma glucose at 40 min postprandially compared with the yellow potato meal (p = 0.044).
The results of this study suggest that anthocyanin-containing purple-fleshed potatoes influence the postprandial insulinemia positively.