Start by identifying exactly what question the information is trying to answer and whether it concerns general education, a diagnosis, a treatment decision, medication safety or an emergency. General educational information can be researched independently, but online information should not substitute for professional assessment when symptoms could represent serious disease. NHS guidance notes that not everything found online is trustworthy, accurate or up to date.
A useful first step is therefore to prioritise authoritative sources such as national health services, government health agencies, major academic medical institutions, recognised professional organisations and reputable evidence-synthesis organisations. WHO similarly advises asking who produced the information, when it was produced, how the claims are known and whether the source is reliable.
Examine who created the content and what qualifications or expertise they have. Reliable medical information should make authorship and organisational responsibility reasonably clear. Look for named authors, relevant professional expertise, editorial oversight, institutional affiliation and a way of identifying who is accountable for the material. A website with a professional appearance is not necessarily medically reliable, and a person with genuine qualifications may still be making claims outside their area of expertise. Anonymous articles, influencer posts and commercial pages deserve additional scrutiny because it may be difficult to determine who is responsible for the claims. WHO recommends considering the author, source of claims and reliability of the information outlet rather than judging credibility from presentation alone.
Check the evidence supporting the claims. A credible health article should distinguish established evidence from hypotheses, expert opinion and anecdotal experience. Look for references to systematic reviews, meta-analyses, randomised controlled trials, authoritative guidelines or other appropriate primary research. Then consider whether the cited evidence actually supports the specific claim being made.
A study showing an association does not necessarily prove causation, an animal study does not automatically demonstrate an effect in humans, and a small uncontrolled experiment cannot establish effectiveness with the same confidence as a well-designed randomised trial. A common warning sign is a dramatic claim supported only by testimonials, isolated case reports or references that do not actually examine the intervention or outcome being discussed.
Examine the date and whether the information has been updated. Medical knowledge changes as new evidence becomes available, and recommendations about medicines, screening, vaccination, diagnosis and treatment can change when new evidence or safety information emerges. An undated article is therefore harder to evaluate. A recent article is not automatically more accurate, however, because recency cannot compensate for weak evidence or poor methodology. Ideally, check the publication or review date, the date of the underlying evidence and whether the organisation maintains an update process. NICE, for example, has formal processes for surveillance and updating guidelines, illustrating why currency is part of evidence quality.
Consider commercial interests and incentives. Ask whether the website sells a product, receives advertising revenue, earns commissions from referrals, promotes a particular clinic or has another financial interest in persuading readers. Commercial involvement does not automatically make information false, but undisclosed or poorly managed conflicts can influence which evidence is presented and how benefits and risks are described. Be especially cautious when an article moves rapidly from describing a health problem to recommending the site's own supplement, test, treatment or subscription. WHO advises considering whether online information is trying to sell something, while NHS resources warn that online medicine sellers may be unsafe and recommend checking appropriate regulatory registration.
Compare the claim against several independent high-quality sources rather than relying on one page. Agreement among independent national health services, professional organisations and evidence reviews increases confidence, although disagreement does not automatically mean that one source is fraudulent. Investigate why sources differ: they may use different populations, outcomes, evidence cut-offs, healthcare systems or definitions. A reliable source should acknowledge uncertainty and limitations rather than presenting every medical question as settled.
If a claim appears only on social media, a commercial website or a small number of highly similar pages, search for the underlying research and see whether independent organisations reach the same conclusion. NHS information resources specifically recommend checking multiple sources and considering whether trustworthy sources provide consistent information.
Evaluate the language and reasoning. Red flags include promises of guaranteed cures, claims that a treatment works for everyone, dramatic statements that doctors or scientists are deliberately hiding a simple solution, conspiracy-based explanations, cherry-picked statistics, unsupported appeals to authority and statements that one study has permanently settled a complex question. Be particularly careful with phrases such as clinically proven when no study is linked, natural therefore safe, chemical-free, detox, miracle cure, or doctors do not want you to know. These expressions can be persuasive without providing meaningful evidence. Strong scientific information is usually more precise about the population studied, intervention, outcome, uncertainty and limitations.
Finally, distinguish information gathering from decision-making. Online research can help someone prepare questions for a GP, pharmacist, dentist or other healthcare professional, understand terminology and compare established options, but it cannot reliably establish an individual's diagnosis from symptoms alone. For medicines, verify dosing, interactions, contraindications and regulatory status using authoritative sources. For urgent symptoms, seek appropriate medical care rather than spending time attempting to confirm a diagnosis online. NHS resources emphasise that trustworthy health information should help people make informed decisions, while WHO recommends obtaining current evidence-based information from trusted health authorities and pausing before sharing uncertain claims.
