Titanium Dioxide TiO₂ in Cosmetics: Toxicology, Regulation, and Scientific Evidence
- annolim
- Jan 7
- 4 min read
Updated: Jan 8
Titanium dioxide (TiO₂) is one of the most widely used ingredients in cosmetic products worldwide valued for its whitening properties and effectiveness as a UV filter in sun protection products. Its long-standing use has made it familiar to cosmetic chemists and consumers alike, but questions about its safety—especially in nano form—have prompted detailed regulatory scrutiny and scientific research.
This article unpacks the toxicological profile of titanium dioxide in cosmetics, focusing on dermal exposure, inhalation risks, and regulatory requirements, supported by scientific literature and safety assessments.
What Is Titanium Dioxide and How Is It Used in Cosmetics?
Titanium dioxide occurs in different particle sizes and crystalline forms:
Micronized (pigmentary) TiO₂ used as a colorant (CI 77891)
Nano-TiO₂ used primarily as a physical UV filter in sunscreens and day creams to reduce opacity while maintaining UV protection. The nano form typically refers to particles <100 nm in at least one dimension, although cosmetic regulatory definitions vary.
Key Toxicological Considerations
Dermal Exposure: Primary Cosmetic Use Route
The most relevant exposure route for most cosmetics is skin contact.
Skin Penetration
Numerous in vitro and in vivo studies show that both micron-sized and nano-TiO₂ particles do not penetrate beyond the outer layer of the skin (stratum corneum) to viable cells or systemic circulation in healthy or compromised skin. This has been confirmed in human and animal studies examining sunscreen formulations.
SCCS Safety Opinion
The Scientific Committee on Consumer Safety (SCCS), the EU’s independent expert body, concluded that nano-TiO₂ up to 25% in dermally applied products does not pose a health risk when applied to healthy or sunburnt skin.
Irritation and Sensitization
Nano-TiO₂ is generally considered non-sensitizing and only mildly or non-irritating to skin. No evidence suggests mutagenicity, reproductive toxicity, or carcinogenicity at typical topical exposures.
Inhalation: Principal Toxicological Concern
While dermal exposure appears low risk, the major concern is inhalation of respirable particles (especially in powders or sprays).
Evidence from Animal Studies
Animal inhalation studies have repeatedly shown lung inflammation and related adverse effects—including, in some high-dose protocols, tumours in lungs. These findings are part of the basis for health hazard evaluations.
Carcinogenic Classification
The International Agency for Research on Cancer (IARC) classified titanium dioxide as “possibly carcinogenic to humans (Group 2B)” based mainly on inhalation evidence from animal studies (limited human evidence).
This classification reflects hazard—not risk at typical consumer exposure levels—and does not imply that dermal use in cosmetics is carcinogenic.
Regulatory Response
Due to the inhalation hazard:
The EU Cosmetics Regulation (EC) No 1223/2009 prohibits use of TiO₂ in sprayable products or loose powders that could lead to consumer inhalation exposure.
SCCS safety opinions distinguish between safe topical uses and unsafe inhalation scenarios.
Oral and Systemic Exposure
Incidental oral exposure (e.g., from lip products) is considered very low and unlikely to result in significant absorption into systemic circulation under normal conditions.
However, regulatory bodies (including SCCS and food safety authorities such as EFSA) continue to monitor genotoxicity and systemic effects for all routes of exposure. Recent SCCS drafts suggest that data gaps remain, particularly regarding genotoxicity potential for some TiO₂ forms used in oral cosmetic products.
Toxicological Mechanisms and Size/Coating Considerations
Nano Form and Surface Coatings
Nano-TiO₂’s small size and high surface area can theoretically increase reactivity and potential for oxidative stress under certain conditions.
Coatings (e.g., silica, alumina-based) commonly used in cosmetic nano-TiO₂ reduce photocatalytic activity and support safety assessments that find negligible dermal penetration and reduced photocatalytic risk.
Current Regulatory Landscape
European Union
Under the EU Cosmetics Regulation (EC) No 1223/2009:
Annex IV lists TiO₂ as a colorant (CI 77891) permitted in cosmetics with purity requirements.
Annex VI lists TiO₂, including nano forms, as a permitted UV filter up to 25% in dermally applied cosmetics.
Use is prohibited in sprayable/powder products with inhalation risk.
These decisions reflect SCCS opinions that emphasize safety for skin application but restrictions on inhalation exposure.
United States
Titanium dioxide is permitted as a color additive in cosmetics under FDA regulation.
It is also recognized as an active sunscreen ingredient, with manufacturers responsible for ensuring safety as part of regulatory compliance.
The FDA has issued non-binding guidance on nanomaterials in cosmetics to help industry characterize and assess risks.
The European Commission published the confirmation document of annulment of the harmonized classification Titanium Dioxide in powder form containing 1% or more of particles with aerodynamic diameter equal to or below 10 μm as Category 2 Carcinogen via inhalation – H351. According to the notice, the Annex I, III and the note W, note 10 in Annex III of Delegated Regulation (EU) 2020/217 are also annulled.
Conclusion
Current scientific evidence and regulatory evaluations consistently show that titanium dioxide is safe for use in cosmetics when applied to the skin and used in compliance with regulatory requirements. The primary toxicological concern—inhalation of respirable particles—is well characterized and addressed through product-format restrictions, particularly in the EU.
Ongoing research continues to refine understanding of nanoforms and oral exposure, ensuring that titanium dioxide remains one of the most thoroughly assessed cosmetic ingredients in use today.
Key Scientific References
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