Rule Of Solubility

When making cosmetics, we tend to learn all about the properties of ingredients and what good does it do to our skin.

However, there is one crucial thing that we miss out. Their solubility! Once we understand this rule of solubility, you will then be able to formulate well, with the right ingredients and even experiment with making new products.

Solubility plays a vital role in making cosmetics. Solubility is when one liquid mixes well with others, making a homogenous mixture. If the ingredient is insoluble, you will see either two layers are made like oil or water, or some powders become lumpy in oils, while some just precipitate. Sometimes when we give it a mix, for a temporary reason they might mix and go with it, but later they separate. Hence it is really necessary to know which ingredients are soluble in what and this is a fundamental rule that you need to know while formulating cosmetics to create stable and effective formulations.

Dividing categories of products based on solubility.

Anhydrous – Lipids, fats waxes. Anything which is oil soluble
Hydrous – Water. Anything which is water-soluble. Even alcohol, glycerin and sometimes honey is used for dissolving certain products.
And when we want to use both of them in a product, we need emulsification.

Emulsification – When oil soluble and water soluble mix with the help of an emulsifier.

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Anhydrous Products – Any products which are oil-based or oil soluble.

Oils, Butters, Waxes, Essential Oils, Emulsifiers, lipid-based thickeners can be added together to create anhydrous products.

Hydrous products – Any product which is water-based.

Hydrosols, decoctions, infusions, humectants, herbal powders, surfactants, natural thickeners or gelling agents can be added together to create anhydrous products. Also, most of the preservatives are water-based, since they are used majorly to protect water-based.

There are certain products where they don’t dissolve well in water, there like said you can use alcohol or glycerine. However, while adding them in formulations, you add them in either water-based products, in the water phase or in the cool-down phase. These solubilisers won’t work in anhydrous formulations since overall, they are hydrous based and not lipid-based.

Emulsions – When you want to mix oil-based ingredients and water-based ingredients together, or if you want to add certain oil-based ingredients to water-based or if you want to infuse some water-based ingredient to the anhydrous product.

For this, you need surfactants, emulsifiers or solubilisers.

Surfactants are water-soluble and can be added to products that as water-based.

For oil-based, you use emulsifiers. Emulsifiers are nothing but surfactants. However, unlike surfactants they don’t lather, are foaming or bubbly. When added to oil-based cleansers, they act as surfactants and help remove extra oil from your face.