Silicones are used as conditioning agents in most hair care products like shampoo, conditioners, treatments and leave-in products.
- Due to their good spreadability, they make a thin film on hair which reduces hair porosity, and prevent hair from absorbing moisture from outside air. That’s how they provide anti-frizz and help in extreme humid condition.
- Lubricates the surface of the hair to provide the slip that helps in wet and dry combing.
- Silicone with refractive index of 1.5 and more reflects light from the hair surface and makes the hair look shiny.
- Because of their silky feel, they are considered as good conditioning agents. Conditioning is different than moisturizing. Moisturizing agents penetrate hair and provide moisture to hair. While conditioning agents work superficially on hair to provide slip and help to lay the cuticles flat over hair surface.
These are not water soluble silicones but evaporate from hair after sometime. So there’s no worry about build up or moisture lock out with these. They are added in products to deliver other ingredients because of their good spreadability on hair. Due to evaporating property, these help hair to dry faster. They distribute into a thin, uniform film before evaporation. They also provide the wet-combing benefit due to their slip.
- Hexamethyl disiloxane
- Octamethyl cyclotetrasiloxane
These silicones can be washed out using water. So you get the benefits of silicone without any concern about their buildup. Any sort of PEG/PPG modified Methicone or Dimethicone belong to this category. For example PEG-8 Dimethicone, PEG-12 Dimethicone. Identify these silicone with PPG- and PEG- in their standard silicone name naming convention (-cone, -oxane, -conol in the end).
- Dimethicone copolyol
- DEA PG-Propyl PEG/PPG-18/21 Dimethicone
- Dimethicone PEG-8 Phosphate
- Dimethicone-PG Diethylmonium Chloride
- PEG-40/PPG-8 Methylaminopropyl/Hydropropyl Dimethicone Copolymer
- PEG/PPG-20/15 Dimethicone
- PEG-12 Dimethicone
- PEG/PPG-20/15 Dimethicone
- PEG-7 Amodimethicone
- PEG-8 Disteramonium Chloride PG-Dimethicone
- PEG-33 (and) PEG-8 Dimethicone (and) PEG-14
Hard to Wash and don’t build Up on themselves
These silicones are generally the ones with names that have “amo”, “amino”, or “amine”. These silicone are highly substantive to hair especially on damaged hair. So, these provide great reduction in forces for wet and dry combing. They make a thin layer on the hair shaft which is hard to remove without a sulfate shampoo. But they do not build up on themselves as subsequent layers are repelled by the first. You need to use a sulfate shampoo to remove these from hair. These are suitable for people who use clarifying shampoo containing lauryl or laureth sulfates or cocamidopropyl betaine on weekly basis. Their deposition rate on hair sometimes depend on other ingredients in the product. They show more deposition rate if they are used with other cationic surfactants like behentrimonuim chloride etc (read more about cationic surfactant) and deposition rate is reduced if they are used with cationic polymer like polyquaternium-X. X could be any number. So, a lot depends on the product formulation.
- Aminopropyl Dimethicone
- Bis-Amino PEG/PPG-41/3 Aminoethyl PG-Propyl Dimethicone
- Bis-aminopropyl Dimethicone
- Dimethicone crosspolymer
- Trimethyl silylamodimethicone
- Vinyldimethicone Crosspolymer
Hard to Wash and builds Up
These silicones are also good conditioner. But repeated use of them leads to build up on hair, causing greasiness, weigh hair down and make hair dry over a period of time. Due to their hydrophobic nature, they are also hard to remove from hair. You have to use a clarifying shampoo and some may even need multiple washes to remove them completely. If these are not removed, moisture can be blocked out of the hair shaft, resulting in dry strands and potential breakage.
- Behenoxy dimethicone
- Bis-Phenylpropyl Dimethicone
- Cetyl dimethicone
- Cetearyl methicone
- Dimethiconol hydroxystearate
- Polysilicone-18 Cetyl Phosphate
- Propyl Dimethicone
- Stearoxy dimethicone
- Stearyl dimethicone
- Stearyl methicone
“Silicones in Cosmetics” Principles of Polymer Science and Technology in Cosmetics and Personal Care In Goddard, E.D. & Gruber, J.V. (Eds.)
Tonya McKay (2006) “WHAT’S THE SCOOP ON SILICONES?” naturallycurly.com.