If you’ve ever wanted to make a cleansing balm that melts into a milky wash, or a lightweight lotion that doesn’t need a degree in chemistry to formulate, Durosoft PG4-O is worth getting to know. It’s a quiet workhorse ingredient that makes oil-to-milk emulsions possible for home and small-batch formulators, without needing high-shear mixers or complicated processes.

This article covers what Durosoft PG4-O actually is, how it works, and where it fits into your DIY skincare and personal care recipes.

What is Durosoft PG4-O?

Durosoft PG4-O is the trade name for Polyglyceryl-4 Oleate, an emulsifier derived from glycerin and oleic acid. Chemically, it belongs to the polyglyceryl ester family, a group of plant-derived, biodegradable emulsifiers that have become popular alternatives to older, harsher surfactant systems.

Polyglyceryl-4 Oleate is a non-ionic emulsifier. It carries no electrical charge, which makes it gentle on skin and compatible with a wide range of other ingredients: actives, oils, and other emulsifiers you might already be using in your formulations.

It’s typically supplied as an amber, oily liquid. That makes it easy to weigh out and blend directly into an oil phase without melting or special handling.

How does an oil-to-milk emulsifier work?

An oil-to-milk emulsifier is exactly what it sounds like: it turns an oil-based product into a milky, water-dispersible one the moment water touches it.

This is the same principle behind cleansing oils and balms that you massage onto dry skin, then rinse off with water. Instead of leaving a greasy film, the product turns cloudy and washes away cleanly.

Durosoft PG4-O achieves this because of its molecular structure. It has a hydrophilic (water-loving) glycerin backbone attached to a lipophilic (oil-loving) oleic acid chain. This dual nature lets it sit at the interface between oil and water, reducing surface tension and allowing the two to blend.

When you add water to an oil phase containing Polyglyceryl-4 Oleate, the emulsifier reorganises itself around tiny droplets of oil, creating a stable oil-in-water dispersion. The result looks milky white, even though the base recipe was mostly oil.

Traditional emulsifiers are usually blended into a formula from the start to create a stable, ready-mixed cream or lotion. With an oil-to-milk system, the transformation happens at the point of use. That’s part of what makes it so appealing for cleansing products.

Why formulators like Durosoft PG4-O

There are a few practical reasons Durosoft PG4-O has earned a place in many DIY formulators’ toolkits.

It’s low-tech to work with. You don’t need a homogeniser or high-shear mixer to get a stable result. A simple whisk or hand blender is usually enough, which makes it accessible for people formulating at home or in a small workshop setting.

It’s plant-derived and biodegradable. Because it’s built from glycerin and oleic acid, it fits comfortably into naturally-derived and green-leaning product lines. That matters to a growing number of customers across South Africa and neighbouring markets who are asking more questions about what’s in their skincare.

It’s gentle. As a non-ionic emulsifier, it doesn’t strip the skin’s natural barrier the way some older surfactant-based cleansers can. That makes it well suited to sensitive skin formulations, including products aimed at dry or reactive skin types.

It’s versatile. Beyond cleansing balms, it can be used in lightweight lotions, milky toners, and even some hair care rinses. One ingredient, several product categories.

Uses in skincare and personal care

Polyglyceryl-4 Oleate shows up across a surprising range of product types. Here’s where it tends to work best.

Cleansing balms and oils

This is the classic use case. A cleansing balm is typically a blend of solid and liquid oils, sometimes with a wax for firmness, plus Durosoft PG4-O to give it the oil-to-milk effect on rinsing. Massaged onto dry skin, the balm dissolves makeup and impurities; add water, and it emulsifies into a milky rinse that leaves skin clean rather than filmy.

Milky cleansers

For a lighter-weight version, formulators use Durosoft PG4-O in liquid cleansing oils that turn milky in the hand or on damp skin, offering a softer sensory experience than a solid balm.

Lightweight lotions

Because it’s a relatively soft, flexible emulsifier, Polyglyceryl-4 Oleate can also be used in low-percentage lotions and body milks where you want a light texture rather than a thick, rich cream. It won’t necessarily replace a primary emulsifier in a full-bodied lotion, but it can support texture and stability in lighter formulas.

Micellar-style and rinse-off products

Its ability to disperse oil in water on contact makes it a natural fit for rinse-off cleansing products more broadly, including some facial washes and even certain hair and scalp treatments where an oil-based active needs to rinse cleanly.

A few formulation tips

Durosoft PG4-O is added to the oil phase of your formulation, generally somewhere in the range of a few percent of the total recipe, though exact usage levels depend on the other oils, waxes, and actives in your specific formula. As with any new ingredient, start with a small test batch to see how it performs with your particular oil blend before scaling up.

It blends well with common carrier oils and butters, and it pairs nicely with other polyglyceryl esters if you want to fine-tune the emulsification and rinse-off behaviour of a product. Because it’s a liquid at room temperature, it’s straightforward to incorporate without extra melting steps, which keeps the process simple for small-batch production.

As always with any new-to-you cosmetic ingredient, patch test finished products before wider use, and keep good records of your ratios so you can repeat, or adjust, a successful formula.

Try it in your own formulations

If you’re formulating cleansing balms, milky cleansers, or lightweight lotions, Durosoft PG4-O is a practical, low-fuss way to bring that oil-to-milk transformation into your own recipes. It’s approachable enough for a first-time formulator, yet versatile enough to keep earning its place in more advanced formulations as your skills grow.

Have a look at our formulation for making your own Oil to Milk Facial Cleanser

Have a look through DIY Naturally’s range of emulsifiers to find Durosoft PG4-O alongside other formulation ingredients, and use it as a starting point for your next cleansing balm or lotion project.