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Propylene Glycol vs Cyclopentasiloxane: which is worse?

Quick answer: Both score equally on our risk model. Propylene Glycol is in the EU and in the US; Cyclopentasiloxane is restricted in the EU and allowed in the US.

PropertyPropylene GlycolCyclopentasiloxane
EU statusRestricted
US statusAllowed
Risk levelmedium
Banned in
Restricted inEuropean Union (not permitted as a direct food additive in most food applications; only permitted as a carrier solvent for specific additives at low levels)European Union
Categoryadditiveendocrine disruptor
Where it hideshair serum, primer, deodorant

What is Propylene Glycol?

Propylene glycol is a synthetic organic compound used as a humectant, solvent, and emulsifier in food, pharmaceuticals, cosmetics, and industrial applications. It is produced from propylene oxide (derived from petroleum). Its chemical formula is C3H8O2.

What is Cyclopentasiloxane?

Cyclopentasiloxane is a volatile silicone (D5) used for smooth, silky texture.

Documented risks

Propylene Glycol: Propylene glycol is generally considered safe by the FDA and is metabolized by the liver to lactic acid and pyruvate (normal metabolites). However, at high doses — particularly from intravenous pharmaceutical formulations — propylene glycol can accumulate and cause lactic acidosis, kidney toxicity, and CNS effects. These effects are seen in critically ill patients receiving high-dose PG-containing intravenous medications, not from food consumption. In children and people with impaired liver or kidney function, PG accumulation may occur at lower doses than in healthy adults. Animal studies have found reproductive and developmental effects at high doses. EFSA's 2018 re-evaluation found no concerns at typical food use levels but noted the EU limits PG use as a direct food additive, using it only as a carrier solvent for permitted additives.

Cyclopentasiloxane: Persistent and bioaccumulative; the EU restricts D5 in wash-off products over environmental and endocrine concerns. The US has no restriction.

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