Meyron

About & methodology

Meyron is a calm, source-linked reference to what published science says about cancer risk. It is written for adults who want to read primary sources instead of headline summaries — no fear-selling, no supplements, no personalised medical advice.

How we source

Every entry in Meyron is anchored to at least one primary source. Where evidence is contested we say so and cite the disagreement. We rely, in order of weight, on:

  • IARC monographs — the International Agency for Research on Cancer's formal evaluations of carcinogenic hazards.
  • WHO — position statements and technical reports from the World Health Organization.
  • WCRF / AICR — the World Cancer Research Fund and American Institute for Cancer Research's Continuous Update Project for diet, nutrition and physical activity.
  • Cancer Research UK (CRUK) — plain-language evidence reviews maintained by the UK's largest cancer research charity.
  • U.S. National Cancer Institute (NCI) — the U.S. federal cancer research and information body.

We do not treat single studies as evidence of risk. Where a reference cites a single trial, it is presented as such.

What the IARC groups mean

IARC classifies agents by the strength of the evidence that they can cause cancer — not by the size of the risk any individual faces, and not by the dose required. The five groups:

IARC Group 1Group 1 — carcinogenic to humans

Strong evidence that this can cause cancer in humans. Examples: smoking, alcohol, UV radiation.

Read more about Group 1
IARC Group 2AGroup 2A — probably carcinogenic

Likely to cause cancer. Evidence in humans is limited, but strong in animals or other studies.

Read more about Group 2A
IARC Group 2BGroup 2B — possibly carcinogenic

Some evidence exists but it is limited or mixed. Less certain than Group 2A.

Read more about Group 2B
IARC Group 3Group 3 — not classifiable

Not enough reliable evidence yet to say whether this causes cancer. This does NOT mean it is safe — it means science has not answered the question.

Read more about Group 3
IARC Group 4Group 4 — probably not carcinogenic

Strong evidence that this is unlikely to cause cancer. Used very rarely.

Read more about Group 4

Editorial policy

Meyron does not offer personalised risk estimates or medical advice. We do not tell readers to buy, avoid, or use any specific product. Where a factor has widely-used consumer references (EWG, Prop 65, Yuka), we link to them for context only — not as endorsements.

Corrections are welcome. Email us at hello@meyron.co.

Full source list

Every organisation cited across the reference:

Trademarks

"IARC", "WHO", "WCRF", "AICR", "Cancer Research UK", "NCI", "EWG", "Dirty Dozen", "Skin Deep", "Proposition 65", "Yuka" and other organisation and product names are trademarks of their respective owners. Meyron is not affiliated with or endorsed by any of them; they are cited as sources.

Not medical advice

Meyron is an educational reference. It is not a diagnostic tool and does not replace consultation with a qualified clinician. If you have a specific personal health question, please talk to a healthcare professional.