What is it? Propanediol is a humectant and solvent derived from corn sugar. It is a good natural alternative to propylene glycol.
INCI Propanediol
Appearance Semi-viscous clear liquid
Usage rate 1–20%, though I find it can feel draggy beyond 3%—this does depend on the formulation, though!
Texture In products it tends to be smooth, but too much can be draggy
Scent Nothing very noticeable, slightly sweet
pH 7
Solubility Water
Why do we use it in formulations? It’s a fantastic non-sticky humectant. I’ll often include it in products that I want to be super hydrating (facial lotions, winter products, etc.). I frequently choose it for inclusion in more watery products (things like facial mists, gels, and micellar waters) where a tacky skin-feel would be really noticeable, especially since it can help reduce the stickiness of glycerin.

It helps add clarity and boosts both viscosity and flash-foam in surfactant products. It also increases the feeling of cleanliness on rinse-off.

Do you need it? No, but it’s inexpensive and versatile, so if somewhere you’re shopping will sell you a small amount I’d grab a bottle as part of a larger order.
Strengths It’s a great non-sticky humectant that serves many other purposes (see “why do we use it in recipes?”).
Weaknesses Can be harder to find than other humectants.
Alternatives & Substitutions Vegetable glycerin is a decent alternative, though watch that you don’t include so much in the recipe that it starts to feel sticky. Propylene glycol would be a great alternative as they are very similar.
How to Work with It Include it in your heated water phase or cold-process it if the recipe does not require heating.
Storage & Shelf Life Stored somewhere cool, dark, and dry, Propanediol should last about a year once opened.
Tips, Tricks, and Quirks Propanediol can boost preservative performance!
Recommended starter amount 30mL (1fl oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Propanediol


Posted on

November 27, 2018