What is it? Dimethicone 350 (also known as Dimethylpolysiloxane) is a mid-weight, non-volatile silicone.
INCI Dimethicone
Appearance Semi-viscous clear liquid
Usage rate Up to 80%, though I typically use it in the 1–5% range
Texture Rich, slippy, smooth. Typical of silicones.
Scent Nothing noticeable
Absorbency Speed Slow
Approximate Melting Point Liquid at room temperature
Solubility Oil, silicones
Why do we use it in formulations? Dimethicone 350 adds wonderful slip to our products and helps reduce tackiness. Small concentrations add a really gorgeous, expensive-feeling skin feel. It helps improve spreading, offers skin protection, and conditions the skin and hair. It can also reduce soaping in lotion formulations. It is also an FDA approved skin protectant.
Do you need it? No, but I do love how small concentrations of Dimethicone 350 allow me to work with higher concentrations of good-for-skin ingredients that can make products feel tacky. It’s also a wonderful, super-easy way to improve slip & skin feel.
Refined or unrefined? Dimethicone 350 only exists as a refined product.
Strengths Dimethicone 350 is a very versatile ingredient that improves the skin feel of anything I’ve ever tried it in. It is non-irritating (suitable for those with sensitive skin) and will not aggravate conditions like Pityrosporum Folliculitis (a.k.a. fungal acne).
Weaknesses The biggest weakness of Dimethicone 350 is all the negative myths about it. These myths include the idea that silicones suffocate the skin, cause acne, are toxic, and are bad for sensitive skin. Dimethicone and other silicones have been studied and reviewed extensively by experts around the world and have been continuously found to be not only very safe, but beneficial to the skin. If you have concerns about silicones, please review these resources:

You certainly don’t have to use silicones in your products if you don’t want to, but don’t avoid it based on misinformation 🙂

Alternatives & Substitutions In products where you are using Dimethicone 350 at 5% or less, you could try a higher viscosity version, like Dimethicone 500 or Dimethicone 1000. With that low of a usage rate, the dimethicone will be diluted so much that the thicker version is unlikely to impact the end product much (if a very low viscosity is important to the final product [i.e. if it’s supposed to mist] then swapping in a higher viscosity of dimethicone probably isn’t the best idea).

There are several natural silicone alternatives on the market now, like “LuxGlide” and “LexFeel”. The ones most suitable for replacing Dimethicone 350 are “LuxGlide 350” and “LexFeel 350”. I find the natural alternatives do not offer the same level of slip and richness as Dimethicone 350, so you may want to increase the concentration to compensate.

You could also try rich, slippy oils as an alternative (something like oat oil), though these will not offer the same level of de-tack-ifying and skin smoothing. The importance of this is very formula dependent, and I also find perceptions of stickiness/tackiness are very personal. If you’re not very sensitive to stickiness (or just plain ol’ don’t mind it) you are less likely to notice the loss of silicone in a formulation.

Dimethicone 1.5 is not a good alternative for Dimethicone 350; the 1.5 version is ultra-thin and lightweight, and evaporates quickly. It is much closer to Cyclomethicone and Cyclopentasiloxane than Dimethicone 350.

How to Work with It Include it in the oil phase of your products; it can be hot or cold processed. Check with your supplier for the specific product you have as recommendations can vary.
Storage & Shelf Life Stored somewhere cool, dark, and dry, Dimethicone 350 has an indefinite shelf life.
Tips, Tricks, and Quirks The “350” in Dimethicone 350 indicates viscosity. The higher the number, the more viscous the dimethicone. Dimethicone 500 and 1000 are also fairly readily available to home crafters.
Recommended starter amount 100mL (3.3fl oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Dimethicone 350


Posted on

January 24, 2020