Cyclosiloxanes (D4, D5, D6) Medium Risk

A group of cyclic silicone compounds used in personal care products and as carriers in silicone-based materials. D4 (octamethylcyclotetrasiloxane) is the most concerning. Found in silicone sealants, cosmetics, and hair products.

Health Concerns

  • D4 classified as an endocrine disruptor
  • Potential reproductive toxicity
  • May impair fertility
  • Readily absorbed through skin
  • Found in human tissues and breast milk

Environmental Impact

  • Persistent in the environment
  • Bioaccumulative in aquatic organisms
  • D4 classified as very persistent, very bioaccumulative (vPvB) in EU
  • Detected in air, water, and sediments globally
  • Slow to degrade in water systems

Regulatory Status

EU restricts D4 and D5 in rinse-off cosmetics above 0.1%. Canada declared D4 toxic under environmental protection act.

What to Avoid

Silicone sealants with high cyclosiloxane content, cyclomethicone and cyclotetrasiloxane in personal care products

Safer Alternatives

Titanium-catalyzed silicone sealants (lower D4), acrylic sealants, cyclosiloxane-free personal care products, natural oils

Products That May Contain This Chemical

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