Our sources
We prioritise, in this order:
- Government and public-health bodies — NIH Office of Dietary Supplements, NCCIH, National Eye Institute, CDC, FDA, MedlinePlus, EFSA.
- Peer-reviewed research — randomised trials, systematic reviews and meta-analyses.
- Academic reference centres — such as the Linus Pauling Institute at Oregon State University.
- The seller’s own pages — for prices, ingredients, terms and contact details only.
We open and read every source before we cite it, and we list sources at the end of each page.
How we check product facts
Prices, shipping, the guarantee and contact details are taken from the seller’s sales page, returns policy and terms of service on the date shown on each page. When sources disagree (for example, two different prices for the same bundle), we report the discrepancy or confirm before publishing.
How we write about health
- We say supplements may support or have been studied for an effect — never that they diagnose, treat, cure or prevent disease.
- We state the doses used in research and whether a product’s doses are known.
- We point out when evidence is weak, small, or funded by an interested company.
- We highlight drug interactions and groups who should avoid a product, and we tell readers with symptoms to see a doctor.
Reviews and testimonials
We never invent reviews, star ratings, customer counts or “verified buyer” badges. We publish reader experiences only with permission and only if they seem genuine, and we publish negative experiences as readily as positive ones.
Updates and corrections
We review key pages regularly and whenever the seller changes prices or terms. If you spot an error, please contact us. We correct factual errors promptly and update the date on the page.
Frequently asked questions
Do you test the product yourselves?
Our reviews are based on the label information, the seller’s terms and the published research. We say clearly what we could and could not verify.
Who checks the health information?
Quoc Nguyen, MSc, a biology scientist, checks the research summaries.
*These statements have not been evaluated by the Food and Drug Administration. Visivra is not intended to diagnose, treat, cure, or prevent any disease. This page is general information, not medical advice — talk to your doctor or eye-care professional before starting any supplement, especially if you are pregnant, nursing, take medication or have an eye condition.