Body & health myths
Health advice gets passed down, half-remembered, and repeated with total confidence — including some that's genuinely important to get right. A fact-checked correction, with sources you can actually trace.
Medicine & the immune system
Myth
The claim: Vaccines cause autism.
Actually: This claim traces to a single 1998 study that was later retracted for data manipulation and scientific misconduct; its lead author lost his medical license. Since then, large studies covering millions of children across multiple countries have consistently found no link between vaccines and autism.
Myth
The claim: Antibiotics work against colds, flu and other viral infections.
Actually: Antibiotics target bacteria; they do nothing against viruses. Taking them for a viral illness doesn't help you recover and contributes to antibiotic resistance — a major reason health authorities emphasize the distinction.
Brain & mind
Myth
The claim: Some people are 'left-brained' (logical) and others are 'right-brained' (creative).
Actually: Certain functions do skew toward one hemisphere (language, for instance, is often more left-lateralized), but a large brain-imaging study of over a thousand people found no evidence that individuals have a dominant hemisphere driving a logical-vs-creative personality type.
Myth
The claim: Reading in dim light permanently damages your eyesight.
Actually: It can cause temporary eye strain and fatigue, but there's no evidence it causes lasting damage. Your eyes simply have to work harder in low light, the same way muscles tire during exercise.
Everyday body myths
Myth
The claim: You lose most of your body heat through your head.
Actually: The idea traces to a flawed mid-20th-century military study. Heat loss is roughly proportional to how much skin is exposed — if your head happens to be the only uncovered part in cold weather, of course that's where the heat escapes, but the head has no special heat-radiating power of its own.
Myth
The claim: You must drink eight glasses of water a day.
Actually: There's no solid scientific basis for that specific number. Hydration needs vary by person, climate and activity level, and are met through a combination of drinks and food — a widely cited review of the evidence found the '8x8' rule was never based on rigorous research.
For the general-purpose body myths — the tongue map, hair growth after death, cracking your knuckles — see common misconceptions. For the biology of blood, senses and evolution, see science myths. This page is educational, not medical advice — talk to a qualified professional about anything that affects your own health.