Cyclopentasiloxane is a silicone-based cosmetic ingredient used in personal care formulations for its smooth spreading, lubricating, and sensory-modifying properties. It is a cyclic siloxane commonly known as D5 (decamethylcyclopentasiloxane) and is valued for its lightweight application feel and volatile character.
Cyclopentasiloxane can help cosmetic products spread evenly across the skin or hair while providing a silky, smooth feel during application. As it evaporates, it may help reduce the perception of a heavy or oily residue, depending on the formulation and the other ingredients present.
This ingredient has been used in selected skin care products, hair serums, conditioners, makeup products, antiperspirants, and other personal care formulations. Its suitability depends on the intended application, grade quality, formulation compatibility, and applicable regulatory requirements.
For cosmetic manufacturers, grade selection is important because purity, physical properties, and regulatory status can influence the ingredient's suitability. The supplier's technical data sheet (TDS), certificate of analysis (COA), and safety data sheet (SDS) should be reviewed before commercial use.
Cyclopentasiloxane is a cyclic silicone compound identified by the INCI name Cyclopentasiloxane. Its chemical name is decamethylcyclopentasiloxane, and it consists of a ring of five alternating silicon and oxygen atoms with methyl groups attached to the silicon atoms.
Unlike Cyclomethicone, which can refer to a mixture of cyclic siloxanes, Cyclopentasiloxane specifically identifies the D5 compound. It has a defined molecular formula and molecular weight.
Cyclopentasiloxane is generally a clear, colourless liquid with low water solubility and a relatively volatile profile compared with non-volatile silicone materials such as Dimethicone. It is used as a spreading agent, carrier for compatible ingredients, and sensory modifier in suitable cosmetic formulations.
Its volatility can contribute to a smooth application experience followed by a lighter residual feel. However, the evaporation rate and finished-product performance depend on the formulation, concentration, processing conditions, and packaging.
1. Smooth Spreading
Cyclopentasiloxane helps cosmetic formulations spread smoothly and evenly over the skin or hair. This is useful in products where consistent distribution and a comfortable application experience are important.
2. Lightweight Sensory Profile
It can provide a silky, lightweight feel during application without the heavy sensation associated with some richer oils and emollients. The final sensory effect depends on the complete formulation.
3. Volatile Carrier Properties
Cyclopentasiloxane can serve as a carrier for selected compatible cosmetic ingredients. Its evaporation after application can help reduce the residual sensation of heaviness.
4. Improved Hair Application
In compatible hair serums, leave-in conditioners, and styling products, it can improve glide and help distribute the formulation along the hair strands.
5. Makeup Formulation Support
Cyclopentasiloxane can be considered for selected foundations, primers, and other colour cosmetics where smooth application, spreadability, and a lightweight finish are desired.
6. Silicone-Based Formulation Compatibility
It can be combined with selected silicone ingredients and compatible oils to help achieve targeted spreading, lubrication, and sensory properties. Compatibility testing remains necessary.
7. Texture Modification
Depending on its concentration and the other ingredients used, Cyclopentasiloxane can influence product slip, application feel, spreading behaviour, and the texture perceived during use.
Cyclopentasiloxane is generally incorporated into compatible silicone-containing or oil-based formulation systems. The appropriate method depends on the grade, intended application, and finished-product requirements.
Important regulatory consideration: The European Union has introduced restrictions on D4, D5, and D6 under REACH. For D5, the restrictions on wash-off cosmetic products have applied since 31 January 2020. The broader restriction includes a 6 June 2026 date, with a separate transition date of 6 June 2027 for specified cosmetic products other than wash-off products. Confirm the current legal requirements, applicable exceptions, and the actual D5 and D4 content before placing products on the EU market.
EUR-Lex
+1
When evaluating Cyclopentasiloxane for cosmetic manufacturing, consider the following quality and procurement requirements:
The identity, quality, and regulatory suitability of the actual supplied grade should be verified before commercial formulation work.
Cyclopentasiloxane is a cyclic silicone ingredient used in selected skin care, hair care, makeup, and personal care formulations for its spreading, lubricating, and sensory-modifying properties. Its suitability depends on grade quality, formulation requirements, and the regulations governing the finished product.
Cosmetic manufacturers should confirm the ingredient identity, purity, impurity profile, technical documentation, and applicable regulatory requirements before use. Laboratory formulation trials, packaging compatibility checks, and appropriate stability assessments are recommended before scaling up production.
1. What is Cyclopentasiloxane?
Cyclopentasiloxane is a cyclic silicone compound, also known as decamethylcyclopentasiloxane or D5. It is used in selected cosmetic formulations to support spreading, lubrication, and a lightweight sensory feel.
2. What is the CAS number of Cyclopentasiloxane?
The CAS number of Cyclopentasiloxane is 541-02-6. The identifier should be confirmed against the documentation for the actual commercial grade.
3. What is the molecular formula of Cyclopentasiloxane?
The molecular formula is C₁₀H₃₀O₅Si₅.
4. What is the molecular weight of Cyclopentasiloxane?
The molecular weight is approximately 370.77 g/mol.
5. Is Cyclopentasiloxane soluble in water?
Cyclopentasiloxane has very low water solubility and is generally considered water-insoluble. Its compatibility with other formulation ingredients should be evaluated during product development.
6. What is Cyclopentasiloxane used for in cosmetics?
It is used in selected skin care products, hair serums, conditioners, makeup products, and other personal care formulations to improve spreading, glide, and application feel.
7. Can Cyclopentasiloxane be used in hair care products?
It can be considered for suitable hair serums, leave-in conditioners, and styling formulations, subject to grade suitability, product safety assessment, and applicable regulations.
8. What is the difference between Cyclopentasiloxane and Cyclomethicone?
Cyclopentasiloxane specifically refers to D5, a cyclic siloxane with a defined molecular formula. Cyclomethicone is a broader ingredient name that may refer to mixtures of cyclic siloxanes, depending on the grade and applicable nomenclature.
9. How should Cyclopentasiloxane be stored?
Store it in a tightly closed, compatible container under the supplier-recommended conditions. Follow the SDS for handling precautions and measures to minimise evaporation.
| Parameter | Specification |
|---|---|
| Appearance | colourless liquid |