Dimethicone, Methicone and Substituted-Methicone Polymer Ingredients

Safety Information

Dimethicone, methicone and substituted-methicone polymers have been reviewed extensively by scientific experts and authorities around the world.   

U.S. Food and Drug Administration (FDA)  

The U.S. Food and Drug Administration (FDA) reviewed the safety of dimethicone and approved its use as a skin protectant in over-the-counter (OTC) drug products at concentrations from 1% to 30%. Dimethicone is also an FDA-approved food additive (antifoaming agent).

Expert Panel for Cosmetic Ingredient Safety 

In 2003, the Expert Panel for Cosmetic Ingredient Safety reviewed the available literature and safety data for dimethicone, as well as a group of closely related silicone polymers that function primarily as skin and hair conditioning agents, and concluded that dimethicone and 19 other silicon-based polymers of dimethicone and methicone  were safe as used in cosmetics.  

According to its procedures, the Expert Panel evaluates the conclusions of previously issued reports approximately every 15 years. In 2019, the Expert Panel reassessed the 20 original ingredients, along with 10 additional alkyl dimethicone and methicone ingredients (highlighted in blue in the table below).  

After review of available literature and safety data, the Expert Panel concluded that the following 30 ingredients are safe in cosmetics in the present practices of use and concentration when formulated to be non-irritating to skin and eyes.  

However, the available data were considered insufficient to determine the safety for use of these ingredients when they are in products that are being applied using airbrush devices, as the data regarding inhalation risk is limited. 

Amino bispropyl dimethicone  Capryl dimethicone 
Aminopropyl dimethicone  Caprylyl methicone 
Amodimethicone  Cetearyl methicone 
Amodimethicone hydroxystearate*  Cetyl dimethicone 
Behenoxy dimethicone  Dimethicone 
C20-24 alkyl dimethicone  Dimethoxysilyl ethylenediaminopropyl dimethicone 
C20-24 alkyl methicone*  Hexyl dimethicone 
C24-28 alkyl dimethicone*  Hexyl methicone* 
C24-28 alkyl methicone  Hydroxypropyldimethicone* 
C26-28 alkyl dimethicone  Methicone 
C26-28 alkyl methicone*  Stearamidopropyl dimethicone* 
C30-45 alkyl dimethicone  Stearoxy dimethicone 
C30-45 alkyl methicone  Stearyl dimethicone 
C30-60 alkyl dimethicone*  Stearyl methicone* 
C32 alkyl dimethicone*  Vinyl dimethicone 

*Not reported to be in current use. If these ingredients are used in the future, they would be used in product categories and at concentrations comparable to others in this group. 

 

All ingredients reviewed by the Expert Panel are listed on the EU’s Inventory of Cosmetic Ingredients (CosIng). Their use as cosmetic ingredients is not restricted in any way according to the general provisions of the Cosmetics Regulation of the European Union. 

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an acceptable daily oral intake level for dimethylpolysiloxane (dimethicone) of 0 to 1.5 mg/kg body weight.  

MYTH: Silicones like dimethicone will make your hair fall out. 

FACTS: There is no scientific evidence to support the claim that silicone pollymers in shampoos and conditioners result in hair loss.  

The Journal of Investigative Dermatology summarized this as follows: Silicone-based conditioners, containing ingredients such as dimethicone, aid in smoothing the hair cuticle and increasing hair smoothness and luster. Following water rinsing of a shampoo or conditioner, the silicone is left behind as a thin coating over each individual hair shaft to fill in visible defects in the hair cuticle, improving combing ease. Increased hair friction snags the hair as the comb is drawn for grooming purposes, resulting in hair breakage. This is the most common cause of significant hair loss. Silicones smooth the hair cuticle and coat each individual hair shaft to decrease friction. 

Resources

Dimethicone, Methicone and Substituted-Methicone Polymer Ingredients

What Is It?

Dimethicone (also known as polydimethylsiloxane; a silicon-based polymer) is a man-made molecule comprised of repeating units called monomers. Silicon is the second most abundant element in the Earth’s crust (after oxygen). Dimethicone is one of the most widely used ingredients in cosmetics and personal care products and can also be found in many cooking oils. 

Methicone and substituted-methicone polymer ingredients are also silicon-based polymers. Each repeating silicon atom is linked with hydrogen (-H), methyl (-CH3) or other substituents. For example, “methicone” means that most of the silicon atoms in the polymer backbone each have 1 methyl group and 1 hydrogen atom.

Why Is It Used?

According to the web-based International Cosmetic Ingredient Dictionary and Handbook (wINCI), dimethicone works as an antifoaming agent, skin protectant, skin-conditioning agent, hair-conditioning agent and solvent. Most of the other ingredients reviewed on this webpage also function as skin and hair conditioning agents and/or viscosity-increasing agents.  

Dimethicone prevents water loss by forming a barrier on the skin. Like most silicon-based polymers, it has a unique fluidity that makes it easily spreadable and, when applied to the skin, gives products a smooth and silky feel. It can also help fill in fine lines/wrinkles on the face, giving it a temporary “plump” look.