bilberry

botanical

What is it

Bilberry (Vaccinium myrtillus) is a small, dark blue-purple berry related to the North American blueberry, found wild across northern Europe. Its fruit is rich in anthocyanin pigments and is used in supplements for eye, vascular, and circulatory health.

How it works

Bilberry's primary bioactive compounds are anthocyanins, the dark purple pigments that give the berries their color. Bilberry is particularly rich in these compounds, with concentrations several times higher than common blueberries. Anthocyanins are powerful antioxidants that may protect vascular endothelial cells and small blood vessels from oxidative damage. In the eye, bilberry anthocyanins are thought to support microcirculation in the retina and potentially affect the regeneration of rhodopsin, the visual pigment involved in night vision. This is the basis for the often-repeated (though largely anecdotal) claim that British WWII pilots ate bilberry jam to improve night vision. Modern clinical evidence for night vision benefits is mixed and generally underwhelming. Bilberry may also support venous and capillary integrity through effects on small blood vessels. Some preliminary research suggests benefits for chronic venous insufficiency and reduced capillary fragility. Antioxidant and anti-inflammatory effects may underlie broader vascular benefits, though clinical evidence varies by condition.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Chronic venous insufficiency

Grade C

Moderate evidence

Small trials suggest bilberry extract may modestly improve symptoms of chronic venous insufficiency, such as leg heaviness and swelling. Evidence quality is limited.

Diabetic retinopathy (supportive)

Grade C

Moderate evidence

Some studies suggest possible modest benefit from bilberry as adjunct in diabetic retinopathy, attributed to antioxidant effects on retinal microvasculature. Evidence is preliminary.

Capillary fragility

Grade C

Moderate evidence

Bilberry anthocyanins may support small blood vessel integrity. Older clinical trials suggest benefit for capillary fragility, though modern controlled evidence is limited.

Night vision and visual function

Grade D

Mixed evidence

Despite popular claims, controlled trials of bilberry on night vision in healthy adults have shown mixed and largely negative results. The wartime British pilot story is anecdotal and not supported by good clinical evidence.

Eye strain and visual fatigue

Grade D

Mixed evidence

Limited evidence suggests possible modest improvement in visual fatigue symptoms with bilberry use. Evidence is preliminary and small-trial-based.

4 commercial forms

Standardized bilberry extract

Typically 25% anthocyanosides

Most common modern form. Provides concentrated anthocyanins for therapeutic applications.

Bilberry powder (dried fruit)

Lower concentrated anthocyanin content

Whole-food form. Can be used in smoothies or as supplement filler.

Fresh or frozen berries

Whole-food form; seasonal availability

Traditional form. Provides anthocyanins along with fiber and other nutrients.

Liquid extract

Alcohol or glycerin-based extraction

Used in tinctures and combination eye health products.

Dosage

There is no established RDA. Standardized bilberry extracts (typically 25 percent anthocyanosides) are commonly dosed at 80 to 480 mg per day, divided into multiple doses. Fresh berries provide much lower concentrated anthocyanins per serving. Most trials use standardized extracts rather than whole fruit for therapeutic applications.

When and how to take it

Bilberry can be taken with or without food. Taking with meals may improve absorption of fat-soluble anthocyanin metabolites and reduce mild gastrointestinal effects. For visual or circulatory support, daily use over several weeks is typical. Divided doses (morning and evening) may help maintain anthocyanin exposure. There is no strong evidence for a specific time-of-day requirement.

Food sources

Food	Amount	%DV
Fresh wild bilberries	1 cup (~100g)	—
Bilberry jam (traditional)	Variable anthocyanin content	—
Frozen bilberries (where available)	1 cup	—

Safety

Bilberry is generally well tolerated. Mild gastrointestinal upset is the most common side effect. High doses of concentrated extracts may cause looser stools. There is no established Tolerable Upper Intake Level. Long-term safety appears favorable in available studies, though most data come from shorter trials.

Who should be cautious

People taking anticoagulants or antiplatelet medications should use caution with concentrated bilberry extracts. Those scheduled for surgery should discontinue at least two weeks before. People with diabetes should monitor blood glucose if starting regular use. Pregnant and breastfeeding women: whole-food bilberry is generally safe, but high-dose extracts should be avoided due to limited safety data.

Interactions

Bilberry may have mild antiplatelet effects and could theoretically increase bleeding risk when combined with anticoagulants like warfarin, antiplatelet drugs, or NSAIDs. Effects on blood glucose are possible at high doses, requiring monitoring in people with diabetes. No major drug-bilberry interactions are well documented at typical supplement doses.

Frequently asked questions

Does bilberry really improve night vision?⌄

Despite the popular WWII pilot story, controlled trials have not consistently shown night vision benefits in healthy adults. The story is largely anecdotal. If you have night vision concerns, see an eye care professional.

Is bilberry the same as blueberry?⌄

They are related species in the same genus (Vaccinium), but bilberries are smaller, darker throughout (not just the skin), and contain higher concentrations of anthocyanins. They are not interchangeable for high-dose supplement effects.

How long until I notice effects?⌄

For most applications, daily use over 4 to 12 weeks is typical before judging effects. Short-term acute effects are minimal.

Is bilberry safe with blood thinners?⌄

Concentrated bilberry extracts may have mild antiplatelet effects. Use caution if you take warfarin, aspirin, or other antiplatelet medications, and discuss with your prescriber.

Can I just eat blueberries instead?⌄

Blueberries provide similar anthocyanin compounds but at lower concentrations than bilberries. Both contribute beneficial polyphenols to a healthy diet, but a clinical-trial-strength dose of bilberry compounds is hard to achieve from blueberries alone.

References

Wikidata: Vaccinium myrtillus — Wikidata link

Track bilberry with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.