Cold-pressed, refined, solvent-extracted - the extraction method changes the chemistry of a plant oil entirely. Here is why it matters to your skin barrier, and why we do not compromise on it.
A bottle of rosehip oil can cost $8 or $80. Both can truthfully call themselves "rosehip oil." But what is inside those two bottles at a molecular level may be almost entirely different. The difference comes down to extraction.
What happens when you cold-press a seed
Cold-pressing is a mechanical process. Seeds are cleaned, dried to an appropriate moisture level, and passed through a hydraulic or screw press that crushes and squeezes the oil out without applying external heat. The oil is then filtered and bottled. No solvents. No chemical intervention.
The result is an oil that retains its full complement of bioactives: tocopherols (naturally occurring vitamin E), phytosterols, carotenoids, and the specific fatty acid profile that makes each seed oil therapeutically distinct. These compounds are heat-sensitive and solvent-sensitive. They do not survive refining intact.
A refined seed oil is structurally an oil. A cold-pressed seed oil is structurally an oil plus its entire botanical complexity.
Linoleic acid (Omega-6) is an essential fatty acid and a structural component of ceramides in the human skin barrier. It cannot be synthesised by the body and must be obtained externally — topically or through diet. Research has linked linoleic acid deficiency in the skin to increased transepidermal water loss and susceptibility to inflammatory barrier conditions including atopic dermatitis.
Where cold-pressing makes the most meaningful difference is not the fatty acid backbone itself it is the surrounding bioactive complex. Cold-pressed oils generally exceed refined oils in their nutritional value, retaining more natural beneficial compounds including tocopherols, sterols, carotenoids, and phospholipids, which are partially removed as a result of refining. PubMed
The research is specific about which refining stages cause the most loss. The loss rate of antioxidant capacity during neutralisation alone ranges from 46–52%, followed by bleaching at 19–31%, with the reduction attributed to the removal of phytosterols, tocopherols, polyphenols, and carotenoids. Wiley Online Library
Tocopherol and sterol losses during refining vary from 10–75% depending on the oil type and process resulting in a measurable decrease in oxidative stability. Cambridge Core
Cold-pressing involves no heat, no chemical treatment, and no refining which allows for the maintenance of a high level of bioactive phytochemicals that would otherwise be reduced or removed.
The four-stage refining process
Most commercial plant oils used in skincare — even those marketed as "natural" — have been refined. The standard refining process has four stages, each one removing something.
Degumming: Phospholipids and proteins are removed using hot water or acid treatment. These compounds include lecithins, which have genuine skin-barrier affinity. They are stripped because they affect appearance and shelf stability, not because they are harmful.
Neutralisation: Free fatty acids are removed with sodium hydroxide (caustic soda). Free fatty acids contribute to the unique therapeutic profile of each oil in rosehip, for instance, they include the linoleic acid fraction responsible for most of its studied skin effects.
Bleaching: Activated clay removes colour compounds primarily carotenoids and chlorophyll. Carotenoids are potent antioxidants. They are removed because consumers, historically, have preferred colourless oils. Sea buckthorn refined to colourlessness is sea buckthorn without its most compelling compound.
Deodorisation: High-temperature steam stripping removes volatile compounds, including much of the remaining tocopherol fraction. The result is a stable, pale, odourless oil that performs consistently batch to batch — and has very little of the bioactive content that made the original plant worth using.
Why we built Seed Glow as a blend, not a single oil
No individual seed provides the full complement of fatty acids, antioxidants, and phytonutrients that support the range of things we ask skin to do. Rosehip is exceptional for its retinoid precursors and linoleic content.
Every oil in the Seed Glow blend is sourced with Certificate of Analysis documentation for each batch: fatty acid profile, peroxide value, free fatty acid content, and tocopherol levels. These numbers tell us whether the oil we received is genuinely cold-pressed or whether it has been blended with a refined fraction a practice that is more common in the supply chain than most consumers would be comfortable knowing.
We do not source on price. We source on chemistry. This creates supply challenges and cost pressures that we accept as part of the work.