Diabetic retinopathy

Overview

No supplement shows clear benefit for diabetic retinopathy. Alpha-Lipoic Acid (WA 32; very low effect size, low evidence, medium trust) at 600 mg daily did not prevent macular edema in a large trial. Probiotics (WA 44; low effect size, low evidence, medium trust) showed no meaningful benefit.

Lutein did not improve vision versus placebo in early trials. Bilberry (160 mg daily) improved swelling and blood flow in one small six-month study. Garlic powder improved vision and eye pressure versus placebo in one short trial, but evidence remains low trust. See the heatmap and evidence reviews below.

Effect graph

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Relevant supplements

Relevant supplements sorted by DEX Score.


Vitamin D	★★★★★	Low
Probiotics	★★★★★	Low
Lutein	★★★★★	Low
Bilberry	★★★★★	Low
Garlic	★★★★★	Very Low / None
Alpha-Lipoic Acid	★★★★★	Very Low / None

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Studies

Find individual evidence reviews for supplements sorted by DEX Score.

6 supplements for and rated at least stars. All purchase bands. No minimum star filter.

Vitamin DView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceMediumTrustMedium

Evidence Review

It is not clear if vitamin D helps people with diabetic retinopathy, an eye problem caused by diabetes.
Some research suggests a weak link between low vitamin D levels and this condition, but there are no studies testing if taking vitamin D helps prevent or treat it.

Browse 1 study1 meta-analysis

Systematic reviewSmoking, dietary factors and major age-related eye disorders: an umbrella review of systematic reviews and meta-analyses2022

An umbrella review found smoking and dietary factors including carotenoids have varying evidence strength for cataract, glaucoma, AMD, and diabetic retinopathy.

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LuteinView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustMedium

Evidence Review

Early research in people with diabetic eye disease shows that taking lutein supplements alone for several months may not improve vision or reduce glare compared to placebo or zeaxanthin alone.
Some studies suggest people with this eye condition have lower levels of lutein and zeaxanthin in their blood, and taking supplements can increase these levels and might help with vision in the future, but more research is needed.

Browse 2 studies

RCTTherapeutic effect of lutein supplement on non-proliferative diabetic retinopathy: A retrospective study2019n=72

In 72 NPDR patients treated with zeaxanthin, adding lutein for 4 months did not significantly improve visual acuity, contrast sensitivity, or glare sensitivity versus zeaxanthin alone.

Effect: No Benefit
Duration: 4 months
Population: Patients with diabetes
Participants: 72

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RCTEffect of lutein supplementation on visual function in nonproliferative diabetic retinopathy2017n=31

In 31 NPDR patients, 36 weeks of lutein 10 mg/day significantly improved contrast sensitivity at 3 cycles/degree and showed a slight VA improvement versus placebo.

Effect: Benefit
Duration: 36 weeks
Dose: 10 mg/day
Population: Diabetic patients
Participants: 31

View on PubMed

ProbioticsView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustMedium

Evidence Review

Probiotics have no meaningful benefit for Diabetic retinopathy.

Browse 1 study

RCTThe effects of probiotics supplements on metabolic indices and clinical signs in patients with diabetic retinopathy, a randomized double blind clinical trial2024n=36

In 55 diabetic retinopathy patients, multi-strain probiotics for 12 weeks lowered insulin and raised QUICKI insulin sensitivity versus placebo without changing other metabolic markers.

Effect: Benefit
Duration: 12 weeks
Population: Patients with diabetic retinopathy
Participants: 36

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BilberryView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustLow

Evidence Review

A small study found that taking 160 mg of bilberry extract every day for 6 months helped improve swelling and blood flow in the eyes of people with diabetic and high blood pressure-related eye problems.
A specific branded bilberry product worked better than a generic version, and it showed extra benefits in patients with certain types of diabetic eye disease.
These results suggest bilberry might help protect the eyes in diabetes, but more research is needed to be sure.

Browse 1 study

ObservationalBilberry extracts are not created equal: the role of non anthocyanin fraction. Discovering the “dark side of the force” in a preliminary study2016n=55

In 140 retinopathy patients, 6 months of Mirtoselect bilberry extract (36% anthocyanins) improved retinal blood flow parameters more than a generic bilberry extract or standard management alone.

Effect: Benefit
Duration: 6 months
Population: Patients with retinopathy
Participants: 55

View on PubMed

Alpha-Lipoic AcidView supplement →

Do not purchase★★★★★

How we scored this

Effect SizeVery Low / NoneEvidenceLowTrustMedium

Evidence Review

Taking 600 mg of alpha-lipoic acid every day did not stop swelling in the eye (called macular edema) in people with early diabetic eye disease, according to a large study.
Vision and blood sugar stayed the same whether people took the supplement or a placebo.

Browse 1 study

RCTAlpha-lipoic acid for the prevention of diabetic macular edema2011n=235

In 235 type 2 diabetes patients followed 24 months, daily oral alpha-lipoic acid 600 mg did not prevent clinically significant macular edema versus placebo (26 vs 30 cases; HR 0.91, p=0.71).

Effect: No Benefit
Duration: 24 months
Dose: 600 mg/day
Population: Patients with type 2 diabetes
Participants: 235
Avg age: ~58

View on PubMed

GarlicView supplement →

Do not purchase★★★★★

How we scored this

Effect SizeVery Low / NoneEvidenceLowTrustMedium

Evidence Review

It is not clear if garlic helps people with diabetic eye disease.
Some early research shows that taking garlic powder daily for a month can improve vision and lower eye pressure better than placebo in people receiving standard treatments for diabetic eye problems.
Garlic might help by reducing inflammation and protecting the eyes, but the studies so far have been small and short, so more research is needed to be sure.

Browse 1 study

RCTEvaluation of the Effect of Garlic Tablet as a Complementary Treatment for Patients with Diabetic Retinopathy2002

In a double-blind RCT of 91 diabetic patients (117 eyes) with macular edema, 500 mg garlic twice daily for 4 weeks did not improve visual acuity, central macular thickness, or intraocular pressure versus placebo.

Effect: No Benefit
Duration: 4 weeks
Dose: 500 mg
Population: Diabetic patients

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Evidence visualised

Same ratings as above, aggregated so you can see coverage and imbalance.

Purchase-guidance distribution

How many supplements fall in each purchase band

Effect-size distribution

How large the reported benefits tend to be

Study distribution across 6 supplements for diabetic retinopathy (7 studies total).
Supplement	DEX	Studies	Meta-analyses	Share
Lutein	★★★★★44%	2	0	29%
Alpha-Lipoic Acid	★★★★★32%	1	0	14%
Bilberry	★★★★★40%	1	0	14%
Garlic	★★★★★32%	1	0	14%
Probiotics	★★★★★44%	1	0	14%
Vitamin D	★★★★★48%	1	1	14%

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Overview

Effect graph

Relevant supplements

Studies

Evidence visualised

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