Plant oils in cosmetics are described by how they were extracted as often as by what plant they came from. The distinction changes both what is in the bottle and how it behaves.
Pressing extracts without heat
Cold pressing uses mechanical force to squeeze oil from seeds or fruit while keeping the temperature low, since heat degrades some of the compounds present.
The oil that emerges carries more than triglycerides. It also contains vitamins, antioxidants, pigments and aromatic compounds from the source material.
Yield is lower than other methods, because pressing does not recover all the oil the plant material holds, which is reflected in cost.
Refining strips the minor components
Refined oils are processed further with heat, filtration and sometimes solvents, removing colour, odour and much of the minor compound content.
What remains is close to pure triglyceride, which is pale, almost odourless and highly consistent from batch to batch.
For a formulator this consistency matters, since a variable ingredient makes a finished product that smells and looks different depending on the season it was made.
Stability runs the other way
The unsaturated fats and minor compounds that give cold-pressed oils their character are also the parts most vulnerable to oxidation.
Refined oils resist rancidity for longer precisely because the reactive components have been taken out, which extends the life of anything they are formulated into.
This is why an unrefined oil is often sold in dark glass with a short recommended period, while a refined one tolerates ordinary storage.
Skin does not read the label
The fatty acid profile drives most of what an oil does on skin, and that profile is broadly similar between the refined and unrefined versions of the same oil.
The minor compounds contribute additional effects, but they are present at low concentrations and their contribution is smaller than the marketing suggests.
Meanwhile the aromatic and protein residues left in unrefined oils are also the components most associated with sensitivity reactions.
Why both remain in use
Unrefined oils suit products sold on their sensory character and short supply chains, where the colour and smell are part of what is being bought.
Refined oils suit formulas that need to be stable, fragrance-free and predictable, including products intended for sensitive or compromised skin.
Neither is straightforwardly better, and a product using a refined oil is making a formulation decision rather than cutting a corner.
Many formulas use both together, taking the bulk of the oil phase from a refined grade and adding a small amount of unrefined oil for its character.