PEG-12 Dimethicone: properties, uses, INCI functions, safety, alternatives
PEG-12 Dimethicone is a chemical compound, derived from silicone, a chemically inert polymer based on silicone. It comes in the form of a colorless transparent liquid. The prefix ''dimeth'' recalls the two methyl groups that are attached to the silicone molecule to form dimethicone. At high temperatures it behaves as a viscous liquid, while at low temperatures it assumes a rubbery behavior. It is resistant to water and UV rays.
The name defines the structure of the molecule:
"PEG-" stands for polyethylene glycol, a polymer based on ethylene oxide. The number that follows "PEG-", in this case 12, indicates the average number of ethylene glycol units in the PEG molecule. Therefore, PEG-12 would have an average of 12 ethylene glycol units.
"Dimethicone" is a type of silicone used for its lubricating and conditioning properties. It is a polymer made up of repeating dimethylsiloxane units, which is a compound consisting of silicon, oxygen, and methyl groups.
The synthesis process takes place in several stages:
Stage 1: Preparation of raw materials: dimethicone and polyethylene glycol.
Stage 2: Reaction. Dimethicone reacts with polyethylene glycol in the presence of a catalyst. This reaction links the polyethylene glycol chains to the dimethicone backbone.
Stage 3: Purification. The resulting PEG-12 Dimethicone is purified to remove any unreacted raw materials and by-products through a series of washing and filtration steps.
Stage 4: Drying. The purified PEG-12 Dimethicone is then dried to remove any residual solvent.
Industrially it is produced in different formats that are distinguished by a number indicating the nominal kinematic viscosity placed after the name. The number appearing after the abbreviation PEG represents the molecular weight and the higher this number is, the less it penetrates the skin.
Dimeticone BP (Poly(dimethylsiloxane) CAS 9006-75-9
Dimethicone USP (-(Trimethylsilyl)- -methylpoly[oxy(dimethylsilylene) CAS 9006-65-9 [–(CH3)2SiO–]n
What it is for and where
It acts as an emulsifier and is used in the cosmetic industry in liquid soaps, shampoos and more. It is a non-neurotoxic topical agent. It is often used in hair products both for its hydrophobic feature that makes the hair smooth and for its high molecular weight that, on the skin, prevents the penetration of exogenous substances, protecting the skin. At concentrations between 1% and 30% it is considered safe. It is mainly an emulsifier and in tablets it has the function of antifoaming.
Hair conditioning agent. A significant number of ingredients with specific and targeted purposes may co-exist in hair shampoo formulations: cleansers, conditioners, thickeners, matting agents, sequestering agents, fragrances, preservatives, special additives. However, the indispensable ingredients are the cleansers and conditioners as they are necessary and sufficient for hair cleansing and manageability. The others act as commercial and non-essential auxiliaries such as: appearance, fragrance, colouring, etc. Hair conditioning agents have the task of increasing shine, manageability and volume, and reducing static electricity, especially after treatments such as colouring, ironing, waving, drying and brushing. They are, in practice, dispersants that may contain cationic surfactants, thickeners, emollients, polymers. The typology of hair conditioning agents includes: intensive conditioners, instant conditioners, thickening conditioners, drying conditioners. They can perform their task generally accompanied by other different ingredients.
Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.
Other uses
Industrial Lubricants - Its combined hydrophobic and hydrophilic properties can make PEG-12 Dimethicone useful in certain lubricant formulations.
Surfactant in Cleaning Agents - Its surfactant properties can help in removing oils and residues in industrial cleaning processes.
Textile Industry - It can be used as an additive to provide a soft finish to fabrics and to help with the uniform distribution of other chemicals during fabric processing.
Agriculture - It can be employed as a spreader or wetting agent for agricultural sprays to ensure even distribution and coverage of pesticides or herbicides on plants.
De-foaming Agent - Silicone derivatives like PEG-12 Dimethicone can act as antifoaming agents in industries where foam can be problematic, such as in certain manufacturing processes.
Ink and Coatings - The compound can help modulate the flow and spreading properties of inks and coatings.
Medical Devices - In some contexts, silicone derivatives can be used in medical device manufacturing, either as part of the device material or as a lubricant.
Alternatives
| Option (INCI) | Product type | Key advantages |
|---|---|---|
| Polyglyceryl-4 Isostearate | Non-ethoxylated emulsifier/solubilizer | Supports emulsification and oil solubilization, useful to reduce/avoid PEGs; good fit in balanced O/W systems. |
| Polyglyceryl-10 Laurate | Non-ethoxylated solubilizer/co-emulsifier | Helps microemulsions and fragrance/light-oil solubilization, suitable for “PEG-free” positioning. |
| Caprylyl/Capryl Glucoside | Nonionic surfactant/solubilizer (APG) | Non-ethoxylated, strong solubilization, improves clarity in gels/sprays, strong natural-origin positioning. |
| Hydrogenated Lecithin | Phospholipid emulsifier (soy/sunflower-derived) | Supports lamellar systems, improves sensory and barrier-like feel, useful for silicone-free skin-feel emulsions. |
| Squalane | Lightweight emollient (plant-derived) | Provides slip and silkiness (not a solubilizer), helps replace part of dimethicone-like silky feel in leave-on products. |
Most significant studies
Dimethicone is considered to be a safe and highly effective treatment for lice in pediatrics (1) definitely better than permethrin.
Effective in the treatment of Actinic Keratoses on the face (2).
Effective in the management of reflux oesophagitis (3).
Safety
Safe as used in cosmetic formulations (4).
For more information:
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Typical characteristics of commercial product Octamethyltrisiloxane (Dimethicone)
| Appearance | Transparent colorless liquid |
| Viscosity | 1.0 cSt(25 °C) |
| Purity | 99% |
| Melting point | -82 °C |
| Boiling point | 153 °C(lit.) |
| Vapor density | >1 (vs air) |
| Flash point | 37.2°C |
| Specific Gravity | 0.82 |
| D4 content % | <0.1 |
| Shelif life | 24 months |
- Molecular Formula : C8H24O2Si3
- Linear Formula: [(CH3)3SiO]2Si(CH3)2
- Molecular Weight : 236.533 g/mol
- CAS : 9016-00-6 107-51-7 9006-65-9 556-67-2
- UNII 9G1ZW13R0G
- EC Number: 203-497-4
- DSSTox Substance ID:
- MDL number MFCD00008264
- PubChem Substance ID 24870584
- InChl 1S/C8H24O2Si3/c1-11(2,3)9-13(7,8)10-12(4,5)6/h1-8H3
- InChI Key CXQXSVUQTKDNFP-UHFFFAOYSA-N
- SMILES C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C
- IUPAC dimethyl-bis(trimethylsilyloxy)silane
- ChEBI 9147
- NACRES NA.23
Synonyms :
- Octamethyltrisiloxane
- Octamethyl-Trisiloxane
- Polydimethylsiloxane
- Dimethicone
- Polidimetilsilossano
- Poly(oxy(dimethylsilylene)), alpha-(trimethylsilyl)-omega-methyl-
- Trisiloxane, 1,1,1,3,3,5,5,5-octamethyl-
- alpha-(Trimethylsilyl)-omega-methylpoly(oxy(dimethylsilylene))
- Dimethyl polysiloxane, dimethyl-terminated
- Dimethylbis(trimethylsilyloxy)silane
- dimethyl-bis(trimethylsilyloxy)silane
- Dimethyl polysiloxane, bis(trimethylsilyl)-terminated
