Ingredient
Cyclotetrasiloxane
Cyclotetrasiloxane is flagged for pregnancy, trying to conceive, PCOS and general use. The concern behind the strongest flag is endocrine disruptor and absorbed into the body.
- D4
- Octamethylcyclotetrasiloxane
- Cyclic Silicone D4
Verdict by profile
Truva checks every ingredient against six profiles. Jump to any of them for the full assessment.
- Strongest verdict
- Caution Advised
- Its verdict for pregnancy, the profile this one is worst in
- Profiles flagged
- 4 of 6
- Counting avoid, high risk and medium risk
- Irritancy
- 0 of 5
- Higher means more likely to sting or redden
Cyclotetrasiloxane and pregnancy
Caution Advised
- Endocrine disruptor
- Absorbed into the body
Cyclotetrasiloxane (D4) is a cyclic silicone that gives cosmetics a smooth, silky feel and helps them spread easily on skin. It's volatile, meaning it evaporates after application, leaving other beneficial ingredients on the skin without a heavy residue. According to the European Chemicals Agency (ECHA), D4 has been classified as a substance of very high concern due to potential endocrine-disrupting properties. Animal studies have shown effects on fertility and fetal development at high exposures. While human skin absorption is considered low (estimated at 0.3-0.5%), the ingredient's classification as a potential endocrine disruptor raises theoretical concerns during pregnancy, a period of heightened hormonal sensitivity. The EU has restricted D4 in wash-off cosmetic products to concentrations of 0.1% or less as of 2020 due to environmental persistence and bioaccumulation concerns. While acute toxicity risk is low, many dermatologists and pregnancy resources suggest choosing products without D4 as a precautionary measure, particularly given the availability of alternative silicones without these concerns.
Cyclotetrasiloxane and breastfeeding
Safe to Use
Cyclotetrasiloxane has low dermal absorption and is highly volatile, meaning it evaporates from skin rather than being absorbed systemically. Studies estimate less than 1% dermal penetration, which minimizes the potential for transfer to breast milk. While D4 has raised concerns about endocrine disruption, the low systemic absorption from topical application and its volatile nature mean that breastfeeding exposure to infants would be negligible. There are no documented cases of D4 transfer to breast milk affecting breastfed infants. For breastfeeding mothers, topical use of products containing D4 is considered low risk. However, if you prefer to avoid ingredients with any endocrine disruption concerns, alternative silicones like dimethicone or cyclopentasiloxane are available in many formulations.
Cyclotetrasiloxane and postpartum
Safe to Use
Cyclotetrasiloxane provides cosmetic benefits by creating a smooth texture in skincare and makeup products. For postpartum women not breastfeeding, the primary concerns with D4 relate more to environmental impact than personal health effects from topical use. While D4 has been flagged for potential endocrine effects in animal studies, the low dermal absorption from cosmetic use means systemic exposure is minimal. For women not pregnant or breastfeeding, the ingredient is generally considered safe for topical use, though environmental considerations may influence product choices.
Cyclotetrasiloxane and trying to conceive
Caution Advised
- Fertility effects
- Endocrine disruptor
Cyclotetrasiloxane has shown reproductive and fertility effects in animal studies, which led to its classification as a substance of very high concern by ECHA. While human skin absorption is low and the relevance of high-dose animal studies to cosmetic use is debated, women trying to conceive often prefer to minimize exposure to potential reproductive toxicants. The precautionary principle suggests avoiding ingredients with documented fertility effects in animal models during the preconception period, even though topical exposure levels are far below those used in toxicology studies. Many fertility specialists recommend choosing products without D4 when equally effective alternatives exist.
Cyclotetrasiloxane and PCOS
Caution Advised
- Endocrine disruptor
Cyclotetrasiloxane has been classified by ECHA as having potential endocrine-disrupting properties based on animal studies. For women with PCOS, a condition already characterized by hormonal imbalance, exposure to potential endocrine disruptors is a theoretical concern, though direct evidence linking topical D4 to PCOS symptom worsening is lacking. The dermal absorption of D4 is low (less than 1%), and the ingredient is volatile, evaporating from the skin rather than accumulating in the body. However, some women with PCOS prefer to avoid ingredients with any potential hormonal activity as a precautionary approach to managing their condition. While there's no strong evidence that topical D4 significantly impacts PCOS, given the availability of alternative silicones without endocrine disruption concerns, many women choose to select products formulated without D4. This is more of a precautionary choice than a response to proven harm.
Cyclotetrasiloxane and general use
Caution Advised
- Endocrine disruptor
- Environmental pollutant
Cyclotetrasiloxane (D4) is a cyclic silicone widely used in cosmetics for its ability to create smooth textures and help products spread easily. It's volatile, meaning it evaporates after application, which prevents buildup on skin but contributes to environmental accumulation. The European Chemicals Agency classified D4 as a substance of very high concern in 2018 due to its persistence, bioaccumulation, and potential toxic effects on the environment. Animal studies have also shown endocrine disruption and reproductive effects at high doses. While dermal absorption from cosmetics is low (less than 1%), the ingredient's environmental impact and potential health concerns have led to increased regulatory scrutiny. The EU restricted D4 in wash-off cosmetic products to 0.1% or less as of 2020 under REACH regulations. In the US, the FDA has not restricted D4, but many companies are reformulating to use alternative silicones like cyclohexasiloxane (D6) or dimethicone due to consumer demand and environmental considerations. For individuals concerned about endocrine disruptors or environmental sustainability, choosing products without D4 is advisable.
Everything else flagged for the same profiles
Related ingredients
Ingredients suggested in place of Cyclotetrasiloxane, each one with its own page here.
Ingredients that raise the same concerns.
Where this came from
Truva summarises published guidance from bodies including ACOG, the FDA, the EU SCCS and the Cosmetic Ingredient Review. It has no access to your medical history and it is not a substitute for your doctor, dermatologist or midwife. These assessments have not been reviewed by a clinician, and nothing here is a diagnosis or a prescription. If you are pregnant, breastfeeding or being treated for PCOS, take the ingredient list to the person looking after you.
Assessment last pulled from the ingredient database on .
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