Humectants in cosmetic formulas – the unsung heroes
Written by Belinda Carli, 10/2026
You may have heard me call humectants the unsung heroes of a cosmetic formula. But do you know the full benefits they can provide not just within a cosmetic formula, but to the skin and delivery of active ingredients?
Read on to find out…
What are humectants?
Humectants are water soluble substances that attract and absorb moisture from the air or deeper layers of the skin. In cosmetic formulas, they provide an instantly more supple appearance to the skin by hydrating the skin from within and smoothing out fine lines and wrinkles. They can also give the skin an immediately more subtle glow.
Common examples you would regularly see in cosmetic formulas include glycerin, propylene glycol, pentylene glycol and propanediol. These can be found across all types of moisturising lotions and creams as well as some hair care products. More advanced cosmeceutical formulas may also include sodium hyaluronate (commonly referred to as hyaluronic acid) and sodium PCA; while you may also find urea in more restorative personal care or therapeutic formulas.
Humectants are not oils
It is a common misconception that humectants are like oils in a cosmetic formula. This is not correct, as humectants are always water soluble and absorb easily to the mid-layers of the epidermis. They are totally non-greasy and perfect for all types of skin. Oils, by comparison, are lipid soluble substances and can have a greasy after-feel, such as plant oils, butters and lipid esters. Their use needs to be considered carefully for the long term sensory benefits and needs of different skin types.
Here is a summary table comparing humectants and lipids:
| Humectants | Lipids/Oils |
| Completely water soluble | Oil soluble |
| Added/compatible with the water phase of a formula | Need a surfactant, emulsifier or solubilising material to be dispersed in water |
| Hold water within the surface layers of the skin for a supple appearance | Form a film on the surface of the skin to protect against moisture loss |
| Some can feel a little tacky/sticky but never greasy | Can feel greasy – selection for skin feel is important for spread, initial and long term sensory |
| Important in moisturisers to hold moisture within the skin and give a supple appearance | Important in moisturisers to add emolliency and skin feel while protecting against moisture loss by providing a moisture protective barrier on the outer layers of the skin |
| Examples: glycerin, propylene glycol, butylene glycol, sodium hyaluronate, sodium PCA | Examples: plant oils, esters, mineral oils, silicones, butters |
Humectants can benefit cosmetic formulas
Humectants are considered osmolytes – they can help carry actives to the mid-layers of the epidermis (stratum granulosum) and provide a more supple, dewy appearance to the skin. Actives are often paired with a humectant or in a humectant base (including butylene and pentylene glycol) to enable them to be pulled to the stratum granulosum level.
The more common humectants, such as glycerin, propylene glycol and propanediol can also be used in cosmetic formulas to help slurry natural gums or other powdery substances. This can make it much easier to add natural gums or other materials to a cosmetic formula, without the risk of clumping or formation of insoluble powder-like ‘fish eyes’.
Common humectants include:
| Recommended Input | Processing Considerations | Ideal for… | |
| Glycerin | 1.0 – 10.0% (more than 5% may feel tacky) |
Tolerates heat, shear and extreme conditions | Natural products; ideal for slurry use. |
| Propylene Glycol | 1.0 – 10.0% | Tolerates heat, shear and extreme conditions | Synthetic; ideal for slurry use; will reduce foaming and viscosity in surfactants. |
| Propanediol | 1.0 – 10.0% | Tolerates heat, shear and extreme conditions | Natural products; ideal for slurry use; much more expensive than glycerin but not tacky. |
| Hyaluronic acid/ Sodium hyaluronate (100% powder) |
0.1 – 1.0% | Add <40°C; low shear only; protect against oxidation |
High end cosmeceutical products (expensive); Not suitable to slurry gums. |
| Sodium PCA (Sodium pyrrolidone carboxylic acid) |
2.0 – 5.0% | Tolerates heat and shear; best pH<7.0 |
Highest performing of all humectants; high end cosmeceutical products (expensive); synergistic effect with sodium hyaluronate. Not suitable to slurry gums. |
Start including humectants in your cosmetic formulas today!
Read more about hyaluronic acid in cosmetic formulas in this blog or watch additional information with this video on how to select hyaluronic acid for cosmetic formulas.
Watch this video to learn how to make a hyaluronic acid gel with sodium PCA.
Learn how to maximise cosmetic active penetration with this video on cosmetic penetration enhancers, utilising humectants.
And of course, humectants are a fantastic addition to serums! Learn how to formulate gel-based serum formulas with this video; or learn how to formulate lotion-like serum formulas with this video.
Happy formulating!
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