Source hierarchy
We rely on, in order of preference:
- Public-health and government bodies — NIH ODS, NCCIH, National Eye Institute, CDC, FDA, MedlinePlus, EFSA.
- Peer-reviewed research — randomised trials and systematic reviews.
- Professional and academic bodies — the American Academy of Ophthalmology, the Linus Pauling Institute.
- The seller’s own documents — only for prices, ingredients, contact details and terms.
Every source is opened and read before it’s cited; sources are listed on each page.
Checking product facts
Prices, delivery terms, the guarantee and contact details come from the seller’s sales page, returns policy and terms of service on the date shown. If sources disagree, we flag the difference or confirm before publishing.
Writing about health
- Supplements “may support” or “have been studied for” an effect — never diagnose, treat, cure or prevent.
- We state research doses and whether the product’s doses are known.
- We flag small, short or industry-funded studies.
- We highlight interactions and at-risk groups, and send readers with symptoms to a doctor.
Reviews and testimonials
We never fabricate reviews, ratings, customer counts or “verified buyer” badges. Reader experiences appear only with permission and when they seem genuine; negative experiences are published as readily as positive ones.
Updates and corrections
Key pages are reviewed regularly and whenever the seller changes prices or terms. Spotted an error? Contact us — we fix factual mistakes promptly and update the page date.
Common questions
Do you test Visivra yourselves?
Our guide is based on the label information, the seller’s terms and published research; we state what we couldn’t verify.
Who reviews the science?
Quoc Nguyen, MSc, a biology scientist.
*The Food and Drug Administration has not evaluated these statements. Visivra is not intended to diagnose, treat, cure, or prevent any disease. We publish general information, not personal medical advice: please check with your doctor, pharmacist or eye-care professional before starting a supplement — particularly during pregnancy or breastfeeding, alongside medication, or with an existing eye condition.