You open your phone for a minute and come away with three new rules: no fruit after 4 p.m., a supplement for your hormones, a test that will finally explain your tiredness. Each one is delivered with total confidence, often by someone who looks healthy and kind.
It is confusing because the posts contradict each other, and some of them are right. Accurate science tends to be slower and less exciting than a bold claim, so the careful voices are often the quietest in your feed.2
This guide walks you through how common misleading advice is, why it travels so well, and a handful of questions that help you judge any post. Then it covers products sold with health claims, a few checks before you act, and when advice becomes risky.
Start with the feed itself: how much of what you see is misleading, why it spreads so well, and what that confusion sounds like in everyday life.
Misleading health posts are common on every platform#
A review of 69 studies found misleading health posts in every area it looked at. In some studies they made up 87% of posts, and diet and eating content sat at around 36%.1
The review defined health misinformation as a claim that rests on anecdote, is false, or is misleading because the science is not there. The topics studied most were vaccines, drugs and smoking, chronic diseases, pandemics, eating disorders and medical treatments.1
A second review of 57 studies found nutrition and cancer among the recurring topics, and noted that accurate science, which can be hard to follow and even dull, is easily crowded out by sensational content.2
Health misinformation, in one sentence
A health claim that is false, rests only on personal stories, or goes further than the science allows.
Surprising claims travel further than careful ones#
False claims tend to be more surprising, and surprise travels. Across about 126,000 stories on Twitter, false news spread farther and faster than the truth, and people, not automated accounts, drove the difference.3
The same study found that false stories were more novel than true ones and drew replies expressing fear, disgust and surprise.3 Those are exactly the feelings a health scare or a miracle claim is built to trigger.
Health content follows the same pattern. Two cancer specialists reviewed 200 of the most shared cancer articles: about a third contained misinformation, most of that was potentially harmful, and the harmful articles were shared and liked more than the safe ones.4
So the posts that reach you first are not a fair sample. The useful skill is knowing what to look at.
Every video says something different#
It tends to sound like this: every video says something different, you no longer know whom to believe, or you tried something you saw online and are not sure it helped.
- Every video says something different
- I don't know who to believe
- I tried what an influencer recommended
- Doctors never mention this
- Is this supplement worth it?
- My feed is full of tests to buy
- It worked for them, why not for me?
- I feel guilty about what I eat
Understand the health advice you read better
Seven short questions, and one of our experts reviews your case personally, then goes through it with you on a free call.
You do not need a science degree to judge a post. A few questions about the person, the evidence and the numbers do most of the work.
Check who is speaking, what they cite and what they sell#
Look at who is speaking, what they cite and what they sell. When researchers checked nine verified influencer blogs on weight management, credibility ranged from 23% to 85%, and the highest belonged to a registered nutritionist.5
Across 64 studies of online nutrition information, almost half found that quality or accuracy was low. Social media and websites did about as well, or as badly, as each other; what mattered more was who published the information.6
| Question to ask | Why it helps |
|---|---|
| Who is this person, and what is their training? | Credibility varied widely between publishers, and was highest for a qualified nutritionist.56 |
| Do they link to the actual study? | A claim you can check is worth more than one you have to take on trust. |
| Is the study in people, and how many? | A result in cells, animals or ten volunteers is a reason for more research, not for changing your life. |
| Are they selling the answer? | A product, a test or a course attached to the advice is a conflict of interest, even when the person is sincere. |
| Do they say what is uncertain? | Careful sources say where the evidence stops. Certainty about everything is a warning sign. |
One person cannot show what would have happened anyway#
One person, however honest, cannot show what would have happened anyway. Symptoms come and go, people change several things at the same time, and only a comparison group can separate one change from everything else.
Many problems people look for help with, such as bloating, poor sleep or low energy, naturally have better and worse weeks. If you try something during a bad week, the next week is likely to feel better whatever you did. That is why trials compare two similar groups instead of trusting before and after.
Randomised controlled trial, in one sentence
A study in which people are assigned by chance to the treatment or to a comparison, so that the two groups differ only in what is being tested.
Stories are still useful. They tell you what people care about and which questions are worth asking. They just cannot tell you whether the answer is right.
Relative numbers sound bigger than absolute ones#
A relative number on its own can sound far bigger than it is. A 25% reduction in deaths from breast cancer with screening means about 1 fewer death in every 1,000 women screened.7
Researchers who study how health statistics are presented found that leaflets, websites and even medical journals often report benefits in forms that make them look large and harms look small. They recommend absolute risks rather than relative ones, and numbers out of 100 or 1,000.7
So when a post says a food or a habit halves your risk, ask: halves it from what to what? A change from 2 in 1,000 to 1 in 1,000 is a 50% reduction, and also one person in a thousand.
Much health advice online ends with something to buy. Here is what to know about those products, and four checks to make before you act.
Health products are not always what they claim#
Advice attached to a sale deserves a second look. The US regulator flagged 776 supplements with hidden medicines in ten years, and Swissmedic advises against buying medicines online outside a Swiss mail-order pharmacy with a cantonal permit.89
Most of those 776 products were sold for sexual performance, weight loss or muscle building. Some contained more than one undeclared drug, and in recent years more than a third of the flagged samples came from online purchases.8
In 2023 Swissmedic reported people in Switzerland admitted to hospital with low blood sugar after using falsified weight-loss pens bought outside the legal supply chain; in one case the package held an insulin pen.9
Tests are sold the same way. Food IgG panels, for example, are widely advertised for intolerances, yet the European allergy society advises that they should not be used for that purpose, because IgG to a food mostly reflects that you eat it.10
Four checks before you act on a post#
Pause and ask whether it is accurate, find the source, look for absolute numbers, and talk to your doctor or pharmacist before stopping or starting anything. In one experiment, a reminder to think about accuracy improved what people chose to share.11
Most posts are harmless at worst. A few are not, so here is when to act straight away, and how we help you make sense of the rest.
Advice becomes dangerous when it replaces treatment#
Advice becomes dangerous when it replaces treatment you need, or when a product bought online makes you ill. People who chose alternative medicine alone for cancers that could be treated had about 2.5 times the risk of death.13
That study looked at 281 people with non-metastatic breast, prostate, lung or colorectal cancer who declined all conventional treatment. It is rare, but it shows what is at stake when a post persuades someone to say no to effective care.13
We help you sort the advice, alongside your doctor#
Our work sits alongside medical care, never in place of it. We help you sort what you have read into what has good evidence, what is unproven and what does not apply to you, then turn the useful parts into habits you can test.
Most of what genuinely helps is unglamorous: regular sleep, enough movement, a varied way of eating, ways to handle stress and attention to digestion. That is what we work on with you, coordinated with your doctor, and we leave medicines and supplements to a conversation with your doctor.
If you have a pile of saved posts and do not know where to start, talk it through with our care team on a free call. It is a coaching conversation, not a medical consultation.
Quick answers10 questions this guide covers, in short
How much of the health advice on social media is wrong?
A lot, though it depends on the topic. A review of 69 studies found misleading health posts in every area studied, reaching 87% of posts in some studies, with diet and eating content around 36%.1 Read the section
Why do false health claims spread faster than true ones?
Because they tend to be more surprising. In an analysis of about 126,000 stories on Twitter, false news spread farther and faster than true news, and people, not automated accounts, drove the difference.3 Read the section
What do people say when online health advice confuses them?
Usually that every video says something different, that they no longer know whom to believe, or that they tried something they saw online and are not sure it helped. Read the section
How can you tell if a health influencer is credible?
Look at who they are, what they cite and what they sell. In one study of verified influencer blogs on weight management, credibility ranged from 23% to 85%, and the highest was a registered nutritionist.5 Read the section
Why is a personal story not proof that something works?
Because one person cannot show what would have happened anyway. Symptoms come and go, people change several things at once, and only a comparison group can separate the effect of one change from everything else. Read the section
What does 'cuts your risk by 50%' really mean?
Often much less than it sounds. A relative reduction says nothing about how common the problem was to begin with: a 25% reduction in deaths from breast cancer with screening means about 1 fewer death in every 1,000 women.7 Read the section
Should you trust health advice that comes with a product to buy?
Be careful. Products sold with health claims are not always what they say: the US regulator flagged 776 supplements containing hidden medicines over ten years, and Swissmedic advises against buying medicines online outside a Swiss mail-order pharmacy with a cantonal permit.89 Read the section
What can you do before acting on a health post?
Pause and ask whether it is accurate, find the original source, look for absolute numbers, and talk to your doctor or pharmacist before stopping or starting anything. In one experiment, a simple reminder to think about accuracy improved what people chose to share.11 Read the section
When can following health advice from social media be dangerous?
When it replaces treatment you need, or when a product bought online makes you ill. People who chose alternative medicine alone for treatable cancers had about 2.5 times the risk of death of those who had conventional treatment.13 Read the section
Where does a functional approach fit when health advice online is confusing?
Alongside medical care, never instead of it. We help you sort what you have read into what has good evidence, what is unproven and what does not apply to you, and turn the useful parts into habits you can test. Read the section
- Suarez-Lledo V, Alvarez-Galvez J. Prevalence of health misinformation on social media: systematic review. J Med Internet Res. 2021;23(1):e17187. PMID : 33470931. Link
- Wang Y, McKee M, Torbica A, Stuckler D. Systematic literature review on the spread of health-related misinformation on social media. Soc Sci Med. 2019;240:112552. PMID : 31561111. Link
- Vosoughi S, Roy D, Aral S. The spread of true and false news online. Science. 2018;359(6380):1146-1151. PMID : 29590045. Link
- Johnson SB, Parsons M, Dorff T, et al. Cancer misinformation and harmful information on Facebook and other social media: a brief report. J Natl Cancer Inst. 2022;114(7):1036-1039. PMID : 34291289. Link
- Sabbagh C, Boyland E, Hankey C, Parrett A. Analysing credibility of UK social media influencers' weight-management blogs: a pilot study. Int J Environ Res Public Health. 2020;17(23):9022. PMID : 33287374. Link
- Denniss E, Lindberg R, McNaughton SA. Quality and accuracy of online nutrition-related information: a systematic review of content analysis studies. Public Health Nutr. 2023;26(7):1345-1357. PMID : 37138366. Link
- Gigerenzer G, Gaissmaier W, Kurz-Milcke E, Schwartz LM, Woloshin S. Helping doctors and patients make sense of health statistics. Psychol Sci Public Interest. 2007;8(2):53-96. PMID : 26161749. Link
- Tucker J, Fischer T, Upjohn L, Mazzera D, Kumar M. Unapproved pharmaceutical ingredients included in dietary supplements associated with US Food and Drug Administration warnings. JAMA Netw Open. 2018;1(6):e183337. PMID : 30646238. Link
- Swissmedic. Swissmedic issues warning about falsified Ozempic pens. Bern: Swissmedic; 7 July 2023. Link
- Stapel SO, Asero R, Ballmer-Weber BK, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. 2008;63(7):793-796. PMID : 18489614. Link
- Pennycook G, McPhetres J, Zhang Y, Lu JG, Rand DG. Fighting COVID-19 misinformation on social media: experimental evidence for a scalable accuracy-nudge intervention. Psychol Sci. 2020;31(7):770-780. PMID : 32603243. Link
- Roozenbeek J, Freeman ALJ, van der Linden S. How accurate are accuracy-nudge interventions? A preregistered direct replication of Pennycook et al. (2020). Psychol Sci. 2021;32(7):1169-1178. PMID : 34114521. Link
- Johnson SB, Park HS, Gross CP, Yu JB. Use of alternative medicine for cancer and its impact on survival. J Natl Cancer Inst. 2018;110(1):djx145. PMID : 28922780. Link
- Tox Info Suisse. Emergency number 145. Zurich: Tox Info Suisse; accessed 27 October 2026. Link
Researched and drafted with the help of AI, checked against its sources, then reviewed and approved by the FunctionAlps editorial team, which holds editorial responsibility for it. How we use AI
Articles published by FunctionAlps are educational and written within ASCA and EMR scope. They do not replace personalised clinical advice. When findings warrant medical evaluation, we coordinate with a referring physician.