Talc and Cancer: What the Evidence Shows

IARC is the cancer agency of the World Health Organization. On 5 July 2024, a working group of 29 experts there classified talc as probably carcinogenic to humans. That is Group 2A.

The classification rested on three legs, and the order matters.

• Limited evidence for cancer in humans, specifically ovarian cancer.
• Sufficient evidence for cancer in experimental animals.
• Strong mechanistic evidence that talc shows key characteristics of carcinogens, in human primary cells and in experimental systems.

That combination is the whole reason for 2A rather than Group 1. The human evidence alone did not carry it. IARC says Group 2A is the second highest level of certainty that a substance can cause cancer.

IARC's press release is unusually specific about its own doubts.

It says numerous studies consistently showed more ovarian cancer among people who reported using body powder in the perineal region. But the evaluation focused on talc without asbestos. And IARC states that asbestos contamination could not be ruled out in most of the human studies.

It also says biases in how talc use was reported could not be ruled out with reasonable confidence. Because of that, a causal role for talc could not be fully established.

Occupational studies pointed the same way and had their own limits. IARC reports higher ovarian cancer rates among women exposed to talc in the pulp and paper industry. But it says co-exposure to asbestos could not be ruled out. And the finding rested on small numbers of ovarian cancers.

In animals, talc raised malignant tumors in females, in the adrenal medulla and lung. In males it raised a mix of benign and malignant tumors in the adrenal medulla. All of this was in a single species, the rat.

On mechanism, IARC names two key characteristics. Talc induces chronic inflammation. And it alters cell growth, cell death, or nutrient supply. IARC notes a filter it applied here. In reviewing this experimental evidence, the group used only studies where asbestos contamination was highly unlikely.

NCI's PDQ summary on ovarian cancer prevention reaches a different conclusion from the same literature. It says results from case-control and cohort studies are inconsistent. So, in its words, the data are inadequate to support a link between perineal talc exposure and ovarian cancer risk.

The studies it cites show the split clearly.

• A meta-analysis of 16 studies found a relative risk of 1.33, with a 95% confidence interval of 1.16 to 1.45. But no dose-response relationship was found.
• A pooled analysis from the Ovarian Cancer Association Consortium, with 8,525 cases and 9,859 controls, found an odds ratio of 1.24 for genital powder use, with a confidence interval of 1.15 to 1.33. The trend across increasing lifetime applications was not statistically significant, at P = .17.
• A case-control study of African American women, with 584 cases and 745 controls, did find a dose-response: an odds ratio of 1.71 for daily powder use versus 1.12 for less than daily use.
• A cohort study of nurses found no risk, with a relative risk of 1.09 and a confidence interval of 0.86 to 1.37.
• The Women's Health Initiative followed 61,576 women for a mean of 12.4 years, with 429 ovarian cancers. It found no association with ever-use, and a hazard ratio of 1.06 for combined perineal powder exposure.
• A cohort of about 250,000 women across four long-term studies found near-identical risk in never-users and ever-users, with a hazard ratio of 1.08.

Both bodies read the same evidence with different rules. IARC asks whether a hazard can be identified. NCI asks whether an association is established. There is also a pattern in the study designs. Case-control studies ask people to recall past powder use after a cancer diagnosis. Those tend to show more effect than cohorts, where use is recorded before anyone gets sick.

IARC is explicit that talc containing asbestos was not part of this evaluation. That category stays inside the definition of asbestos. IARC classified asbestos as carcinogenic to humans, Group 1, in 2009.

For asbestos, IARC states there is sufficient evidence of mesothelioma. The same holds for cancers of the lung, larynx, and ovary. There is limited evidence for cancers of the pharynx, stomach, and colorectum.

The practical worry is contamination. IARC says accurate measurement is hard. Because of that, contamination of talc with asbestos may still be a concern. It could expose workers and the public through products such as talc-based makeup and body powder.

FDA describes the same problem from the rules side. Under the Federal Food, Drug and Cosmetic Act, cosmetic products and ingredients do not need FDA review before going on sale. Color additives are the exception. FDA monitors for safety problems. But it must have sound scientific data showing harm before it acts.

Anyone reading about talc regulation should check the date on what they are reading.

FDA proposed a rule on testing methods for finding asbestos in talc-containing cosmetics. It was published in the Federal Register on 27 December 2024. Its authority was section 3505 of the Modernization of Cosmetics Regulation Act of 2022.

On 28 November 2025, FDA announced the withdrawal of that proposed rule. It said comments received warranted further consideration before final regulations were issued. So no standardized federal testing method is in force from that rulemaking.

FDA does run its own product testing. Its most recent published survey covered 2023 samples. An outside laboratory did the analysis. It used two methods, polarized light microscopy and transmission electron microscopy. Results were published product by product.

IARC says it plainly. The Monographs programme identifies cancer hazards. That means the potential for an exposure to cause cancer. The classification does not indicate the level of risk at different exposure levels or in different settings. Two agents in the same group can carry very different real-world risks.

FDA's own summary is worth setting beside IARC's. FDA says the scientific literature going back to the 1960s has suggested a possible link between genital powder use and ovarian cancer. But it says those studies have not conclusively shown such a link. Nor have they shown what risk factors might be involved. FDA says more research is needed.

One historical note explains why older material reads differently. The 2024 evaluation supersedes two earlier ones. In 2006, IARC put perineal use of talc-based body powder in Group 2B, possibly carcinogenic, on limited evidence for ovarian cancer. Inhaled talc without asbestos or asbestiform fibers was then Group 3, not classifiable.

How IARC groups are decided is explained in IARC monographs explained. The distinction this page turns on is covered in hazard versus risk. The Group 1 agent behind the contamination worry is covered in asbestos and cancer.

• IARC press release 352: talc and acrylonitrile
• NCI PDQ: ovarian cancer prevention, HP version
• FDA: talc