Dimethicone (DMPS 350): What It Is and How to Use It in Skin and Hair Formulas

Dimethicone (DMPS 350) is a light, colourless, odourless silicone oil with a viscosity of 350 centistokes, used as a conditioning ingredient in creams, lotions, shampoos, conditioners and lipsticks. In simple terms, it forms a thin, breathable film on skin and hair that seals in moisture, adds slip and smoothness, and reduces the stickiness, foaming and whitening of a finished product. It is for external use only.

What is Dimethicone (DMPS 350)?

Dimethicone is also known as Polydimethylsiloxane (PDMS) or dimethylpolysiloxane. It is a silicone oil derived from purified silica — the same family of material found in sand and quartz. The "350" refers to its viscosity: at 350 centistokes it is thicker than water-thin silicones but still pours and spreads easily, which makes it comfortable to work with in a home or small-batch setting.

A few useful specifications for formulators: the INCI name is Dimethicone, the CAS number is 63148-62-9, the specific gravity is around 0.97 g/ml, and it is odourless with a neutral pH range of 5.5–8.5. It is dispersible in water rather than fully soluble, and this variant is industrial grade with a stated purity of around 99% and a shelf life of about 24 months.

Common Uses in Cosmetics

Dimethicone earns its place in formulas because of how it feels and behaves on skin and hair. Typical applications include:

• Moisturisers, creams and lotions: it creates a protective barrier that slows moisture loss and leaves a silky, non-greasy after-feel.
• Shampoos and conditioners: it coats the hair strand, reducing frizz, adding shine and improving comb-through on wet and dry hair.
• Serums and primers: it gives that smooth "blur" and slip that makeup products are known for.
• Lipsticks and balms: it improves glide and helps the product apply evenly.
• Ointments and barrier creams: it helps shield skin from external moisture and friction.

A practical bonus: adding dimethicone can reduce excess foaming, whitening (soaping) and tackiness in a lotion or cream, which is why many makers reach for it when a formula feels too sticky.

How to Use It in Your Formulas

Dimethicone is oil-soluble and dispersible in water, so it is usually added to the oil phase of an emulsion. General guidance for hobby formulators:

1. Weigh dimethicone as part of your oil phase, typically between 1% and 5% of the total formula, depending on the slip and barrier you want.
2. For lotions and creams, blend it into the heated oil phase before combining with the water phase and emulsifying.
3. For leave-on serums or hair oils, it can be added at the cool-down stage since it is heat stable and does not need high temperatures to incorporate.
4. Start low, test the skin-feel, and increase gradually. A little goes a long way — too much can leave a slippery or coated feel.

Because it is water-dispersible rather than water-soluble, expect it to sit as fine droplets in a water-based mix unless properly emulsified.

Safety and Handling

Dimethicone is intended strictly for external application. Keep these points in mind:

• Do not ingest it, and avoid using it internally.
• Avoid applying it over broken skin or if you are dealing with any active skin ailment.
• As with any new cosmetic ingredient, do a small patch test in your finished product before wider use.
• Store away from open flame — the flash point is around 121 °C.
• Keep containers sealed, labelled and out of reach of children.

Always refer to the COA and MSDS for the specific batch you receive.

Buying and Storage Tips

Azlok stocks Dimethicone (DMPS 350) in a range of pack sizes — 100 GM, 500 GM, 1 KG, 5 KG, 10 KG and 20 KG — so you can buy a small quantity to trial a recipe or a bulk pack for regular production. Prices start at ₹199, and the product is manufactured in India.

To keep it in good condition:

• Store in a cool, dry place away from direct sunlight.
• Keep the lid tightly closed to avoid dust and contamination.
• Use clean, dry utensils when scooping or pouring.
• Use within the roughly 24-month shelf life for best results.

FAQ

Is Dimethicone the same as silicone?

Yes, dimethicone is a type of silicone oil, also called Polydimethylsiloxane (PDMS). It is derived from purified silica found in sand and quartz.

What does the 350 in DMPS 350 mean?

The 350 refers to the viscosity in centistokes. It is a moderate viscosity — thicker than very light silicones but still easy to pour and blend into formulas.

Is dimethicone water soluble?

No. It is dispersible in water but not truly soluble. In emulsions it is usually added to the oil phase and then emulsified into the water phase.

How much dimethicone should I add to a lotion?

Most formulators use around 1% to 5% of the total formula. Start low, test the skin-feel, and adjust to get the slip and barrier you want.

Can dimethicone be used on hair?

Yes. It is widely used in shampoos and conditioners to smooth the hair cuticle, reduce frizz, add shine and improve detangling.