One of the most common formulation mistakes in homemade cosmetics is trying to mix essential oils directly into water.
The mixture may look uniform for a few minutes after shaking, but this is temporary. Oils and water are chemically incompatible. Essential oils are lipophilic and water is hydrophilic, so the oil separates and forms microscopic droplets that float freely in the product.
This is not only a stability issue. It is a skin safety issue.
When a spray or toner contains undispersed essential oil, a concentrated droplet may reach the skin directly. Irritation that people often attribute to the essential oil itself is very often caused by improper incorporation into the water phase.
This is the reason solubilizers exist.
what polysorbates arePolysorbate 20 and Polysorbate 80 are non-ionic surfactants used as solubilizers.
Their function is to disperse very small quantities of oils inside water-based formulations such as hydrosols, toners, facial mists and body sprays.
Each molecule has two different parts. One part is attracted to water and the other part is attracted to oil. The solubilizer surrounds the oil droplet and keeps it suspended inside the aqueous phase, forming microscopic structures called micelles.
The oil is not dissolved in the strict chemical sense.
It is evenly distributed.
A properly solubilized product may appear clear or slightly opalescent, but it should not show surface oil after resting.
the difference between Polysorbate 20 and Polysorbate 80Although they belong to the same family, they do not behave identically. The difference is related to the type of lipid material they can accommodate.
Polysorbate 20
Best suited for light aromatic materials.
Works well with:
- essential oils
- fragrance oils
- aromatic extracts
Typical applications:
- facial mists
- toners
- aftershaves
- light body sprays
It gives a lighter skin feel and usually a clearer solution, which makes it preferable for facial use.
Polysorbate 80
Better suited for heavier lipids.
Works with:
- vegetable oils
- oil blends
- bath oils
- thicker aromatic materials
Typical applications:
- bath products
- shower oils
- body products where oil content is higher
Because it accommodates heavier lipids, it often produces a more opaque or cloudy appearance and a richer skin feel.
how to use them correctlyA solubilizer must never be added directly into water first.
Correct method:
- Measure the essential oil
- Add the polysorbate to the oil
- Mix until completely uniform
- Only then add the blend to the water phase
If added directly to water, the solubilization efficiency drops significantly.
typical working ratiosThe required amount depends on the essential oil, but practical formulation ranges are:
Facial mist/ toner (with Polysorbate 20)
Essential oil: 0.2–0.5%
Polysorbate 20: 3–6 parts for each 1 part essential oil
Example:
0.3% essential oil → 1.0–1.8% Polysorbate 20
Body spray
Essential oil: 0.5–1%
Polysorbate 20: 4–8 parts per 1 part oil
Oil-containing water product (with Polysorbate 80)
Oil phase: 1%
Polysorbate 80: 4–10 parts per 1 part oil
If oil appears on the surface after 24 hours, additional solubilizer is required.
important notes- A solubilized product is not an emulsion and does not replace a cream emulsifier.
- Polysorbates are not preservatives. A preservative system is still necessary.
- If the bottle needs shaking before each use, the oil has not been properly solubilized.
- Essential oils should remain at low percentages in leave-on products.
The purpose of using polysorbates is not only aesthetic clarity. It is controlled distribution. Even dispersion prevents concentrated contact between essential oil and skin. A stable formulation is therefore gentler and more predictable in daily use.
In cosmetic formulation, stability and tolerance go together. A product that is properly incorporated is a product that behaves consistently.
If you would like to understand why essential oils must be incorporated this way in the first place, you can read our my safety guide on How to Safely Add Essential Oils to Water-Based Cosmetics.
Polysorbates, however, are not the only option. In the next article we examine PEG-40 Hydrogenated Castor Oil and how it compares in water-based cosmetic formulations.
