Compendium of the most significant studies with reference to properties, intake, effects.

There is no unanimity of conclusions in the scientific literature on the hazardousness and genotoxicity of talcum powder, so we have gathered in two sections the studies that consider talcum powder to be not harmful to human health and the studies that attribute clear negative consequences to talcum powder.

Talcum powder: not harmful

Hildick-Smith GY. The biology of talc. Br J Ind Med. 1976 Nov;33(4):217-29. doi: 10.1136/oem.33.4.217. 

Abstract. Data are presented on the effects on health of talc dusts from exposure in industry and use of talc-containing health products. The mineralogy of talc and the composition of cosmetic and industrial grade talc dusts are described. Studies in animals are reviewed, and epidemiological data are considered in relation to exposures that occur during industrial and consumer uses of talc dusts. Hamsters exposed to 8 mg/m3 of respirable cosmetic grade talc dust for up to 150 minutes a day for 300 consecutive days showed no difference in incidence or nature of pathological lesions from those observed in a group of untreated animals. A retrospective study of the causes of death of 227 talc mine millers exposed to cosmetic grade talc at the threshold limit value for talc (20 million parts per cubic foot) for an average of 15-8 years showed that the causes of death were no different from those in a control cohort not exposed to talc dust. The available data indicate that talc dust exposure in the modern mining of cosmetic grade talc does not appear to be injurious to health. The significantly lower dust exposure in the normal use of cosmetic grade talc dusts in talc-containing health and cosmetic products confirms that their use is not a hazard to health.

Muscat JE, Huncharek MS. Perineal talc use and ovarian cancer: a critical review. Eur J Cancer Prev. 2008 Apr;17(2):139-46. doi: 10.1097/CEJ.0b013e32811080ef. 

Abstract. Talc, like asbestos, is a silicate that has been studied in relation to cancer risk. Several studies conducted over the past 25 years found an association between perineal talc powders and ovarian cancer. The summary relative risk is about 1.3 (95% confidence intervals 1.2-1.5) and these data have been interpreted as supporting a causal role. In this review article, we discuss the chemical and morphological features of talc and asbestos, and explain why despite their similar chemical classification talc does not possess asbestos-like carcinogenic properties. The heterogeneity in the perineal dusting studies has raised important concerns over the validity of the exposure measurements, and the lack of a consistent dose-response effect limits making causal inferences. Perhaps more importantly, whereas it is unknown whether external talc dust enters the female reproductive tract, measures of internal talc exposure such as talc-dusted diaphragms and latex condoms show no relationship with ovarian cancer risk. In addition, the therapeutic use of high dose cosmetic grade talc for pleurodesis has not been shown to cause cancer in patients receiving these treatment modalities. Talc is not genotoxic. Mechanistic, pathology and animal model studies have not found evidence for a carcinogenic effect. In summary, these data collectively do not indicate that cosmetic talc causes ovarian cancer.

Fiume MM, Boyer I, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Andersen FA. Safety Assessment of Talc as Used in Cosmetics. Int J Toxicol. 2015 Jul-Aug;34(1 Suppl):66S-129S. doi: 10.1177/1091581815586797.

Abstract. The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of talc for use in cosmetics. The safety of talc has been the subject of much debate through the years, partly because the relationship between talc and asbestos is commonly misunderstood. Industry specifications state that cosmetic-grade talc must contain no detectable fibrous, asbestos minerals. Therefore, the large amount of available animal and clinical data the Panel relied on in assessing the safety of talc only included those studies on talc that did not contain asbestos. The Panel concluded that talc is safe for use in cosmetics in the present practices of use and concentration (some cosmetic products are entirely composed of talc). Talc should not be applied to the skin when the epidermal barrier is missing or significantly disrupted.  © The Author(s) 2015.

Talcum powder: harmful

Tran TH, Steffen JE, Clancy KM, Bird T, Egilman DS. Talc, Asbestos, and Epidemiology: Corporate Influence and Scientific Incognizance. Epidemiology. 2019 Nov;30(6):783-788. doi: 10.1097/EDE.0000000000001091. 

Abstract. Despite the Cosmetic, Toiletry, and Fragrance Association’s attempts to downplay the elevated risks of ovarian cancer associated with perineal talcum powder use reported in epidemiologic studies, both of the National Toxicology Program scientific panels voted to list talc “not containing asbestos” as a carcinogen. The Cosmetic, Toiletry, and Fragrance Association then threatened the United States National Institutes of Health and National Toxicology Program Report on Carcinogens budgets,and the National Toxicology Program management overruled the science panels. Talc was the only one of the 21 substances nominated for the Report on Carcinogens that the National Toxicology Program withdrew.

Cramer DW. The association of talc use and ovarian cancer: biased or causal. Gynecol Oncol Rep. 2021 Dec 4;41:100896. doi: 10.1016/j.gore.2021.100896. 

Abstract. In a recent review published in Gynecologic Oncology (Wentzensen and O'Brien, 2021), Wentzensen and O’Brien summarized epidemiologic evidence on the association between genital talc use and ovarian cancer. They noted that retrospective case-control studies have shown associations between genital powder use and ovarian cancer with summary relative risk estimates from 1.24 to 1.35. ... The apparent synergistic effect of estradiol with talc provides a biologic basis for our observation that postmenopausal women using estrogen replacement had greater risk for a ovarian cancer with talc use than postmenopausal women who had used talc but hadn’t taken hormone replacement.

Chang CJ, Tu YK, Chen PC, Yang HY. Talc exposure and risk of stomach cancer: Systematic review and meta-analysis of occupational cohort studies. J Formos Med Assoc. 2020 Apr;119(4):781-792. doi: 10.1016/j.jfma.2018.07.015. 

Abstract.  Background/purpose: Talc powder is widely used in various industries, but the carcinogenic effects associated with talc are not well understood. The objective of this study was to estimate the risk of stomach cancer after occupational talc exposure....Conclusion: The available data showed a positive association between occupational talc exposure and risk of stomach cancer. The association between talc not containing asbestiform fibers and risk of stomach cancer was not significant. Further epidemiological studies are required to evaluate the safety of talc. Copyright © 2018. Published by Elsevier B.V.

Moline J, Patel K, Frank AL. Exposure to cosmetic talc and mesothelioma. J Occup Med Toxicol. 2023 Jan 18;18(1):1. doi: 10.1186/s12995-023-00367-5. 

Abstract.  Aim: Mesothelioma is associated with asbestos exposure. In this case series, we present 166 cases of individuals who had substantial asbestos exposure to cosmetic talc products as well as some who had potential or documented additional exposures to other asbestos-containing products and who subsequently developed mesothelioma....Conclusion: Cumulative exposure to asbestos leads to mesothelioma; for individuals with mixed exposures to asbestos, all exposures should be considered. Use of cosmetic talc is often overlooked as a source of asbestos exposure. All individuals with mesothelioma should have a comprehensive history of asbestos exposure, including cosmetic talc exposure. © 2023. The Author(s).

Stoiber, T., Fitzgerald, S., & Leiba, N. S. (2020). Asbestos contamination in talc-based cosmetics: An invisible cancer risk. Environmental Health Insights, 14, 1178630220976558.

Abstract. The aim of this study was to assess asbestos contamination in talc-based cosmetics and to call attention to the outdated methods for screening as well as bring awareness to the potential hazard in cosmetics. With nearly 15% of products contaminated in a small study, methods used by industries to screen talc supplies are not adequate.

Steffen, J. E., Tran, T., Yimam, M., Clancy, K. M., Bird, T. B., Rigler, M., ... & Egilman, D. S. (2020). Serous ovarian cancer caused by exposure to asbestos and fibrous talc in cosmetic talc powders—a case series. Journal of Occupational and Environmental Medicine, 62(2), e65-e77.

Abstract. Objective: Asbestos is a known cause of ovarian cancer. We report 10 cases of serous ovarian cancer among users of Johnson & Johnson (J&J) asbestos-containing “cosmetic” talc products....Conclusion: We provide evidence that the inhaled dose of asbestos/fibrous talc from “cosmetic” talc use causes ovarian cancer. The unique combination of the types of asbestiform minerals detected in cancerous tissue and “cosmetic” talc is a fingerprint for exposure to asbestos-containing talc.

What is Talcum powder

A chemical compound that is produced directly from talc, steatite, sepiolite, a pressed hydrated magnesium silicate, treated with hydrochloric acid, washed and dried. In its composition are available asbestos, amphiboles, chrysotile, aluminum.

The name defines the structure of the molecule:

• Talc. The name is derived from the Arabic word 'talq', meaning 'pure'. It is a reference to its white colour and the softness of the mineral.

The synthesis process takes place in different stages:

• Mother rock formation. Talc is formed from parent rocks rich in magnesium and silica. The mother rock can be dolomite or serpentine.
• Metamorphism. Over millions of years, these rocks undergo metamorphism, a process in which the mineral composition and structure of the rock are changed by heat and pressure. This process can lead to the formation of talc.
• Extraction and processing Once formed, talc is extracted from open-pit mines and then ground into a fine powder for use.

It comes in the form of a fine, odorless, tasteless, white non-sandy powder with a greasy feel to the touch.

What is it for?

Used in a variety of industries: paints, cosmetics, linoleum, textiles, rubber, paper, plastics, talc is a good modifier for elastomers, improves stiffness and barrier properties. Because of its high specific surface area characteristics, talc is used to dust sticky products, prevents agglomeration and improves handling. Talc has acid and fire resistance, insulation, high melting point, strong absorption strength and is chemically inert because of its crystallization due to its layered structure.

Pharmaceutical 

Filling agent, coating of tablets Talc is a gliding excipient, in practice it increases the smoothness of the material in the tablet by reducing the friction between the particles. Typically the concentration is: 0.3-10 %w/w.

Cosmetics

Talc is a restricted ingredient as III/59 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Ingredient at risk: Talc: Hydrated magnesium silicate

• Abrasive agent. It contains abrasive particles to remove stains or biofilm that accumulate on the stratum corneum or teeth. Baking soda, kieselguhr, silica and many others have abrasive properties. Peeling or exfoliating products used in dermatology or cosmetic applications contain abrasive agents in the form of synthetic microspheres, however these microspheres or abrasive particles are not biodegradable and create pollution in aquatic ecosystems.
• Absorbent. Absorbs substances dispersed or dissolved in aqueous solutions, water/oil, oil/water.
• Anticaking agent. This compound facilitates free flow and prevents aggregation or clumping of substances in a formulation by reducing the tendency of certain particles to stick together.
• Bulking agent. It regulates the water content, dilutes other solids, can increase the volume of a product for better flow, acts as a buffer against organic acids, helps to keep the pH of the mixture within a certain level.
• Opacifying agent. It is useful into formulations that may be translucent or transparent to make them opaque and less permeable to light.
• Skin protectant. It creates a protective barrier on the skin to defend it from harmful substances, irritants, allergens, pathogens that can cause various inflammatory conditions. These products can also improve the natural skin barrier and in most cases more than one is needed to achieve an effective result.
• Slip modifier. It increases the spreadability of a product by helping other substances flow more smoothly and easily, without chemical reaction..

Food

Labeled with the number E553b, anti-caking agent, in the European food additives list.

Other uses

Rubber: filling agent (the dosage is 5% of the amount of poly (vinyl acetate)

And also used in printing inks, ceramics, cables, waterproof materials and others

Safety

In recent years, many manufacturers have removed asbestos (a known carcinogenic mineral) from the production of talcum powder because of the dangers that asbestos can create to human health, but some precautions still need to be observed: talcum powder must not come into contact with the horny layer when the latter is damaged.

Among the impurities present in talcum powder processing, aluminium is of some concern. Aluminium can interfere with different biological processes (cellular oxidative stress, calcium metabolism, etc.), so it can induce toxic effects in different organs and systems, and the nervous system is the main target of its toxicity. 

Studies

This study finds that exposure to talc in female genitals produces an increase in inflammation resulting in an increased risk of ovarian cancer (1).

Because of the contained asbestos, talc inhalation can cause pulmonary fibrosis in the form of granulomatous nodules called talcosis. Talc exposure has also been suggested as a causative factor in the development of ovarian carcinomas, gynecological cancers and mesothelioma (2).

This study assessed the risk of contracting asbestos-related disease from powdered cosmetic talcum users. The hypothetical treatment of this fiber as if it were an asbestos involves a risk of 9.6 × 10-7 (less than one in a million) (3).

Some cases of talc poisoning (4) which is believed, in this study, to be cytotoxic (5).

The most relevant studies on this ingredient have been selected with a summary of their contents:

Talc studies

Typical commercial product characteristics

• Molecular Formula : Mg₃(OH)₂Si₄O₁₀   H₂Mg₃O₁₂Si₄   Mg₃(Si₄O₁₀)(OH)₂
• Linear Formula :  ₃MgO·₄SiO₂·H₂O
• Molecular Weight : 379.259 g/mol
• CAS : 14807-96-6
• UNII    7SEV7J4R1U
• EC Number: 238-877-9
• DSSTox Substance ID: DTXSID5032109
• MDL number  MFCD00792903
• PubChem Substance ID 
• InChI=1S/3Mg.4O2Si.H2O.3O/c;;;4*1-3-2;;;;/h;;;;;;;1H2;;;
• InChl Key      FPAFDBFIGPHWGO-UHFFFAOYSA-N
• SMILES    O.O=[Mg].O=[Mg].O=[Mg].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O
• IUPAC dioxosilane;oxomagnesium;hydrate
• ChEBI    

Synonyms :

• Talc CP
• tris(@magnesium oxide) tetrakis(silica) hydrate
• tris(@magnesium oxide) tetrakis(silica) hydrate
• 3MgO.4O2Si.H2O
• E553b

References____________________________________________________________________

(5) Davies R, Skidmore JW, Griffiths DM, Moncrieff CB. Cytotoxicity of talc for macrophages in vitro. Food Chem Toxicol. 1983 Apr;21(2):201-7. doi: 10.1016/0278-6915(83)90237-5. PMID: 6682083.

Abstract. The cytotoxicity of seven specimens of respirable talc dust for mouse peritoneal macrophages in vitro was studied. All talcs showed modest but consistent macrophage cytotoxicity and would be expected to be fibrogenic in vivo. Available data suggest that under certain circumstances respirable talc can cause lung fibrosis in animal inhalation studies. As most of the talc specimens under investigation were of high purity it seemed unlikely that the cytotoxicity was due to the presence of small quantities of contaminating minerals.