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Moumoujus

THORIUM DIOXIDE.

Avoid CAS 1314-20-1 / BINDING, SKIN CONDITIONING

Thorium Dioxide is a highly radioactive and carcinogenic substance with no legitimate application in skincare or cosmetics. It poses a severe radiation hazard upon skin absorption, leading to cellular damage and an elevated risk of cancer. Its historical use in cosmetic products was swiftly banned due to its inherently poisonous nature.

Summary

Science

Mechanism of Action

When absorbed through the skin, Thorium Dioxide undergoes breakdown into other radioactive isotopes within the body. These emit alpha particles that, despite traveling short distances, inflict direct cellular damage. This internal exposure creates an ongoing radiation hazard, significantly increasing the long-term risk of various cancers.

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

Thorium Dioxide is not a legitimate ingredient in cosmetics, thus dusting analysis for consumer safety is not applicable. Its use in any cosmetic form is strictly prohibited due to extreme hazards.

The Formula

Formulation

Solubility
Insoluble
Optimal pH N/A
0 7 14

Stability

Thorium dioxide is a remarkably stable crystalline solid, exhibiting the highest known melting point among all oxides at approximately 3300 °C (3350 °C; 6060 °F; 3620 K). It maintains its integrity under typical temperature and pressure conditions.

Conflicts

  • human exposure
  • cosmetic formulations

Safety

Safety Profile

CIR Status
Not reviewed
Max tested
0%
Pregnancy
Caution
Sensitization risk High

Thorium Dioxide is unequivocally classified as a carcinogen. The U.S. Department of Health and Human Services lists it as reasonably anticipated to be a human carcinogen, and the IARC categorizes internalized α-particle-emitting radionuclides, including Thorium-232, as carcinogenic to humans (Group 1). This substance is radioactive, with no stable isotopes. Exposure can lead to severe health issues, including suppressed white blood cell production, lung scarring from repeated low-level exposure, and damage to the liver and kidneys. Long-term exposure has been associated with symptoms such as persistent coughing, weight loss, breathing difficulties, anemia, cataracts, and heart disorders. Historically, its use in French cosmetics was banned in the 1930s due to its poisonous nature. It is not approved for cosmetic use by any major regulatory body (FDA, CIR, SCCS); it should not be confused with titanium dioxide (TiO2).

Your Skin

Skin Compatibility

No Normal
No Dry
No Oily
No Sensitive
Irritancy High
Comedogenicity Unknown

Our Assessment

Verdict

Avoid

Thorium Dioxide is a highly dangerous, radioactive carcinogen with no safe or legitimate use in skincare or cosmetics, posing severe health risks including cancer and organ damage.

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