What Are Star Ratings?
Our proprietary "Star-Rating" system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by some in the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
Supplement |
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3 Stars
Bilberry Extract and Pycnogenol
Refer to label instructions
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In a preliminary study, supplementation with a product that provided Pycnogenol (a maritime pine bark extract) and a standardized bilberry extract significantly decreased intraocular pressure in people who had elevated intraocular pressure.
In a preliminary study, supplementation with a product that provided daily 80 mg of Pycnogenol (a maritime pine bark extract) and 160 mg of a standardized bilberry extract for two months significantly decreased intraocular pressure in people who had elevated intraocular pressure.
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3 Stars
Ginkgo
120 mg daily of a standardized herbal extract
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In cases of normal tension glaucoma; ginkgo may help improve vision.
In a double-blind study, supplementation with a standardized extract of Ginkgo biloba in the amount of 40 mg three times a day for four weeks partially reversed visual field damage in people with one type of glaucoma (normal tension glaucoma).
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3 Stars
Vitamin C
At least 2 grams daily
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Supplementing with vitamin C may help reduce intraocular pressure.
Several studies have shown that supplementing with vitamin C can significantly reduce elevated intraocular pressure in individuals with glaucoma. These studies used at least 2 grams per day of vitamin C; much larger amounts were sometimes given. Higher quantities of vitamin C appeared to be more effective than smaller amounts.
Doctors often suggest that people with glaucoma take vitamin C to "bowel tolerance." The bowel-tolerance level is determined by progressively increasing vitamin C intake until loose stools or abdominal pain occurs, and then reducing the amount slightly, to a level that does not cause these symptoms. The bowel tolerance level varies considerably from person to person, usually ranging from about 5 to 20 or more grams per day. Vitamin C does not cure glaucoma and must be used continually to maintain a reduction in intraocular pressure.
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2 Stars
Coleus
Consult a qualified healthcare practitioner
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Studies have shown that intraocular pressure may be lowered by directly applying a sterile fluid extract of forskolin, a constituent of the Ayurvedic herb Coleus forskohlii.
Studies in healthy humans, including at least one double-blind trial, have repeatedly shown that intraocular pressure is lowered by direct application of forskolin, a constituent of the Ayurvedic herb Coleus forskohlii. Until ophthalmic preparations of coleus or forskolin are available, people with glaucoma should consult with a skilled healthcare practitioner to obtain a sterile fluid extract for use in the eyes. Direct application of the whole herb to the eyes has not been studied and is not advised.
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2 Stars
Flavonoids
Refer to label instructions
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In one study, supplementation with anthocyanins (a type of flavonoid) significantly decreased the amount of visual field loss in patients with open-angle glaucoma.
In a double-blind study, supplementation with 50 mg per day of anthocyanins (a type of flavonoid) from black currants for 2 years significantly decreased the amount of visual field loss, compared with a placebo, in patients with open-angle glaucoma. The treatment had no effect on intraocular pressure.
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1 Star
Alpha-Lipoic Acid
Refer to label instructions
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Alpha lipoic acid may improve visual function in people with some types of glaucoma.
Alpha lipoic acid (150 mg per day for one month) improves visual function in people with some types of glaucoma.
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1 Star
Bilberry
60 mg twice a day
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In a preliminary trial, supplementing with anthocyanins (flavonoids found in bilberry) improved symptoms in people with normal-tension glaucoma.
In a preliminary trial, supplementing with anthocyanins (a group of flavonoids found in bilberry and certain other plant foods) improved visual acuity and partially reversed visual field damage in patients with normal-tension glaucoma (a type of glaucoma associated with normal intraocular pressure). The amount used was 60 mg twice a day for an average of two years.
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1 Star
Dan Shen
Refer to label instructions
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Dan shen, a traditional Chinese herb, was reported to improve vision in people with glaucoma when given by muscular injection
Dan shen (Salvia miltiorrhiza), a traditional Chinese herb, used either alone or combined with other Chinese herbs for 30 days was reported to improve vision in people with glaucoma. However, the herb was administered by muscular injection, a preparation that is not readily available in North America or Great Britain. It is not known whether oral use of the herb would have the same effect.
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1 Star
Fish Oil
Refer to label instructions
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Inuit people, who eat large amounts of omega-3 fatty acids, appear to have a much lower incidence of glaucoma than do Caucasians. One study found that cod liver oil (a rich source of omega-3 fatty acids) reduced intraocular pressure in animals.
Surveys have shown that Inuit people, who consume large amounts of omega-3 fatty acids, have a much lower incidence of some types of glaucoma than do Caucasians. Although there have been no studies on the use of omega-3 fatty acids to treat glaucoma, one study found that cod liver oil (a rich source of omega-3 fatty acids) reduced intraocular pressure in animals.
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1 Star
Magnesium
Refer to label instructions
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In one study, supplementing with magnesium improved vision in people with glaucoma, apparently by enhancing blood flow to the eyes.
Magnesium can dilate blood vessels. One study looked at whether magnesium might improve vision in people with glaucoma by enhancing blood flow to the eyes. In that trial, participants were given 245 mg of magnesium per day. Improvement in vision was noted after four weeks, but the change did not reach statistical significance.
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1 Star
Melatonin
Refer to label instructions
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Supplementing with melatonin lowered intraocular pressure of healthy people in one study.
Supplementing with 0.5 mg of melatonin lowered intraocular pressure of healthy people, but there have been no studies on the effects of melatonin in people with glaucoma.
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1 Star
Periwinkle
Refer to label instructions
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One double-blind and one preliminary study have found that brovincamine, a compound closely related to periwinkle's active constituent vinpocetine, was helpful in people with chronic glaucoma. Until studies have been conducted using actual vinpocetine, it is unknown whether it would be as effective as brovincamine.
One double-blind and one preliminary study have found that brovincamine, a compound closely related to periwinkle's active constituent vinpocetine, was helpful in people with chronic glaucoma. Until studies have been conducted using actual vinpocetine, it is unknown whether it would be as effective as brovincamine.
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1 Star
Rutin
Refer to label instructions
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The flavonoid rutin may increase the effectiveness of conventional medication in people with glaucoma.
Many years ago, the flavonoid rutin was reported to increase the effectiveness of conventional medication in people with glaucoma. The amount used—20 mg three times per day—was quite moderate. In that study, 17 of 26 eyes with glaucoma showed clear improvement. Modern research on the effects of rutin or other flavonoids in people with glaucoma is lacking.
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