Reference summary — not medical advice or a personal risk estimate.
1-Naphthylthiourea (ANTU)
Quick answer
Classified as Group 3 — not classifiable, based on limited evidence in humans, alongside stronger evidence in animals. Listed by IARC mainly as an industrial or research chemical. Where people are exposed has not been written up here; see the IARC Monograph.
Summary
Classified by IARC as Group 3 — not classifiable as to carcinogenicity. Inadequate evidence. (Vol 30, Sup 7, 1987)
What's not established
This classification means the evidence is inadequate to say whether this factor causes cancer in humans. It does not mean the factor is safe. It does not establish a safe exposure threshold or your personal risk from a given level of exposure.
Regional relevance
global
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
IARC
IARC Monographs — Agents Classified Alphabetically (Vols 1–123)
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.