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MixedHealthLast updated: June 1, 2026

Cell phones cause brain cancer

Major reviews and long-term cohort studies have not found evidence that typical mobile phone use increases brain tumor risk. The IARC classified radiofrequency radiation as possibly carcinogenic (Group 2B) in 2011 based on limited evidence, but newer and larger studies, including a 2024 WHO-commissioned systematic review, do not support an increased risk.

What we know

Cell phones emit radiofrequency (RF) electromagnetic radiation, a non-ionizing form of energy. Ionizing radiation such as X-rays and gamma rays are established carcinogens because they carry enough energy to break chemical bonds and damage DNA. RF radiation does not have sufficient energy for this mechanism, which is an important biological reason why a cancer link has always been considered biologically implausible.

In 2011, the International Agency for Research on Cancer (IARC) classified RF electromagnetic fields as Group 2B, meaning possibly carcinogenic to humans, based on limited evidence from some epidemiological studies suggesting increased glioma risk among heavy users. This is the same category as pickled vegetables and coffee at the time, reflecting uncertainty rather than established danger.

Since then, larger and better-designed studies have not confirmed an increased risk. The COSMOS prospective cohort study, published in 2024 with data from more than 250,000 participants followed for over seven years, found no elevated brain tumor risk in the highest mobile phone users. A 2024 WHO-commissioned systematic review analyzing about 5,000 studies also concluded there was no evidence linking mobile phone use to brain tumors, cognitive decline, or oxidative stress. The Harvard T.H. Chan School of Public Health has noted that the best current evidence is clear that cell phones do not cause brain cancer. Brain tumor incidence trends have also not increased in ways consistent with widespread mobile phone exposure.

Common claims

  • Cell phones cause brain cancerNot supported by current evidence
  • IARC classified cell phones as carcinogenicGroup 2B - possible, lowest evidence category
  • Heavy users have higher cancer riskNot confirmed in large cohort studies
  • 5G signals are more dangerousNo evidence supports increased risk

Evidence hierarchy

01WHO-commissioned systematic review on mobile phone health effects (2024)Most comprehensive analysis to date of approximately 5,000 studies, concluding no evidence of cancer or cognitive risks from mobile phone use within safety limits.02COSMOS prospective cohort study - mobile phone use and brain tumor risk (Environment International, 2024)250,000-participant prospective study finding no elevated brain tumor risk among heavy mobile phone users over 7 years of follow-up.03Cellular Telephone Use and Risk of Brain Tumors (Epidemiology, 2022)Study of 776,000 women finding no significant association between cellular phone use and brain tumor incidence across all subtypes.04NCI Cell Phones and Cancer Risk Fact SheetOfficial NCI summary noting that most studies do not show a link between cell phone use and brain tumor risk.

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