Cyclopentasiloxane vs Saccharin: which is worse?
Quick answer: Saccharin carries the heavier risk profile. Cyclopentasiloxane is restricted in the EU and allowed in the US; Saccharin is — in the EU and — in the US.
| Property | Cyclopentasiloxane | Saccharin |
|---|---|---|
| EU status | Restricted | — |
| US status | Allowed | — |
| Risk level | medium | — |
| Banned in | — | Canada (banned for food use; permitted in medications only) |
| Restricted in | European Union | European Union (ADI 5 mg/kg body weight; must be labeled), United Kingdom, Australia |
| Category | endocrine disruptor | additive |
| Where it hides | hair serum, primer, deodorant | — |
What is Cyclopentasiloxane?
Cyclopentasiloxane is a volatile silicone (D5) used for smooth, silky texture.
What is Saccharin?
Saccharin is the oldest artificial sweetener, discovered accidentally at Johns Hopkins in 1879. It is a sulfonamide compound approximately 300-400 times sweeter than sucrose with no caloric value. It has a slightly bitter metallic aftertaste at higher concentrations. Saccharin's sodium salt (sodium saccharin) is the form used in most food applications.
Documented risks
Cyclopentasiloxane: Persistent and bioaccumulative; the EU restricts D5 in wash-off products over environmental and endocrine concerns. The US has no restriction.
Saccharin: Saccharin's carcinogenicity history is one of the most tumultuous in food regulatory history. In 1977, the FDA proposed banning saccharin after studies found it caused bladder cancer in rats at very high doses. Congress passed the Saccharin Study and Labeling Act, which put a moratorium on the ban and required a cancer warning label on saccharin products ('Use of this product may be hazardous to your health. This product contains saccharin which has been determined to cause cancer in laboratory animals.'). By 2000, saccharin was removed from the US National Toxicology Program's Report on Carcinogens after subsequent research determined that the bladder cancer in male rats was caused by a rat-specific mechanism — high pH, high protein, and calcium phosphate in rat urine — that does not apply to human urine. The cancer warning label requirement was repealed. IARC also removed saccharin from its Group 2B list in 1999. However, Canada maintained its ban on food use saccharin, citing continued precautionary concern. A 2022 study in Cell found saccharin was among the artificial sweeteners most significantly altering gut microbiome composition and glucose tolerance in previously non-sweetener-using participants. Saccharin showed the largest effect on glucose tolerance among the sweeteners studied (saccharin, sucralose, aspartame, stevia). Saccharin passes through the placenta and appears in breast milk, raising questions about infant exposure that have not been fully resolved.
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