Last updated: 20 February 2026
In skincare, botanical oils are often described with terms such as "nourishing", "restoring", or "balancing". These words are mainly sensory; they describe how something feels but do not explain why an oil is more comfortable on one skin type than another. For a professional assessment, it is more useful to look at the chemical reality: fatty acid profiles, stability (oxidation), and the presence of lipophilic micronutrients such as tocopherols and phytosterols.
In this article, we approach cold-pressed oils as lipid mixtures that interact with the epidermal barrier function. If you would first like to read about the basics of lipids and barrier integrity, start with dry skin and the skin barrier – how to support the skin.
Table of contents
- 1. Molecular structure of botanical oils
- 2. Saturated, MUFA, and PUFA – why double bonds matter
- 3. Fatty acid profiles of commonly used cold-pressed oils
- 4. Linoleic acid – barrier, ceramides, and follicular context
- 5. Oleic acid – penetration and barrier interaction
- 6. Lipid oxidation – chain reactions and quality
- 7. Squalene oxidation and its relevance in sebum-rich environments
- 8. Antioxidants in cold-pressed oils – tocopherols and stability
- 9. Interaction with stratum corneum lamellae – why context is everything
- 10. Cold-pressed versus refined – what changes chemically?
- 11. Translation to skin conditions – a chemical perspective
- 12. When botanical oils may be less suitable
- 13. How to identify oil oxidation (Checklist)
- 14. Frequently asked questions
- 15. Conclusion
- Transparency and sources
1) Molecular structure of botanical oils
Most botanical oils consist primarily of triglycerides: esters formed by glycerol with three fatty acid chains. The physical and cosmetic properties of an oil are determined mainly by:
- chain length (typically C16–C22)
- degree of saturation (the number of double bonds)
- the ratio between individual fatty acids
Cold-pressed oils also contain smaller amounts of lipophilic micronutrients, such as tocopherols (vitamin E), phytosterols, and, depending on the oil, phenolic compounds. Although these components do not determine the "bulk profile" of the oil, they can significantly influence its stability and skin comfort.
2) Saturated, MUFA, and PUFA – why double bonds matter
The number of double bonds in fatty acid chains influences both molecular structure and oxidative stability.
Saturated fatty acids (SFAs) have no double bonds; their chains are relatively straight and can pack together compactly. These fatty acids are generally highly oxidatively stable.
Monounsaturated fatty acids (MUFAs) have one double bond (such as oleic acid). This introduces a kink in the chain, which changes its molecular arrangement.
Polyunsaturated fatty acids (PUFAs) have two or more double bonds (such as linoleic acid). Multiple kinks make the chain chemically more reactive and more susceptible to oxidation.
In practical terms, this means that PUFA-rich oils degrade more rapidly when exposed to light, heat, and oxygen, which can affect both their sensory quality and skin comfort.
3) Fatty acid profiles of commonly used cold-pressed oils
The values below are average ranges. Natural variations due to origin, harvest, and processing are to be expected.
| Oil | Linoleic acid (ω-6) | Oleic acid (ω-9) | Stability indication |
|---|---|---|---|
| Jojoba | Predominantly wax esters (no classic triglycerides) | N/A | Very high |
| Argan | ±30–35% | ±40–45% | Medium |
| Rosehip | ±40–50% | ±10–20% | Low |
| Avocado | ±10–15% | ±60–70% | High |
| Hemp seed | ±50–60% | ±10–20% | Low |
| Macadamia | ±3–5% | ±55–65% | High |
It is rarely about finding a single "perfect percentage," but rather about recognizing the overall pattern: linoleic-acid-rich oils (often lighter but more prone to oxidation) versus oleic-acid-rich oils (often richer-feeling and relatively more stable), and how this profile aligns with your skin condition and routine.
4) Linoleic acid – barrier, ceramides, and follicular context
Linoleic acid (C18:2, ω-6) is an essential fatty acid that plays a vital role in epidermal lipid structures. Within the barrier, specific ceramide structures are formed in part in the presence of linoleic acid. This explains why linoleic acid is frequently discussed in dermatological contexts regarding barrier function.
In acne research, it is also noted that individuals with acne-prone skin often present with a lower proportion of linoleic acid in their sebum. This deficiency is associated with alterations in follicular keratinization (microcomedone formation). While this does not imply that linoleic acid treats acne, it provides biochemical context on why fatty acid ratios are relevant in sebum-rich environments.
More context on acne-related processes (sebum, keratinization, and the microbiome): Understanding acne – how skin, hormones, and microbes work together.
5) Oleic acid – penetration and barrier interaction
Oleic acid (C18:1, ω-9) is a monounsaturated fatty acid (MUFA) that dominates the profile of many plant oils. In dermatological research, oleic acid is known as a penetration-enhancing fatty acid, as it can temporarily alter the arrangement of stratum corneum lipids. In an intact skin barrier, this can contribute to a rich, nourishing feel. However, in sensitive or already compromised barriers, this same property can sometimes lead to irritation.
This nuance is key: being "oleic-acid-rich" is not inherently positive or negative. The context—such as barrier health, concentration, and oil stability—determines the outcome.
Read more about skin reactivity and triggers: Sensitive skin – causes, triggers, and gentle care.
6) Lipid oxidation – chain reactions and quality
Fatty acid oxidation is a well-documented chemical process. Because PUFAs contain multiple double bonds, they have more reactive sites vulnerable to oxygen attack. Oxidation typically progresses as a chain reaction in three steps:
1. Initiation
A hydrogen atom is removed from a fatty acid chain (typically triggered by light, heat, or metal ions), creating a free radical.
2. Propagation
The fatty acid radical reacts with oxygen to form a peroxyl radical. This peroxyl radical then reacts with other fatty acid molecules, propagating the chain reaction.
3. Termination
Radicals react with one another to form more stable, non-radical compounds (including aldehydes and ketones). These secondary oxidation products are responsible for the rancid odor and loss of product quality.
In skincare applications, it is important to note that oxidation by-products can be biologically more irritating than the original fatty acids. This is why freshness and proper storage are functionally essential, particularly for PUFA-rich oils.
7) Squalene oxidation and its relevance in sebum-rich environments
Squalene is a natural, highly unsaturated lipid component of human sebum. Under the influence of UV radiation and oxygen, squalene readily oxidizes into squalene peroxides. In scientific literature, squalene peroxides are linked to changes in keratinization and inflammatory responses within the follicular environment.
Although botanical oils do not necessarily share the exact same lipid profile as human sebum, this mechanism illustrates why oxidation is a critical consideration in lipid-rich environments, and why oxidation-prone oils require diligent storage.
8) Antioxidants in cold-pressed oils – tocopherols and stability
Cold-pressed oils naturally contain antioxidants, including tocopherols (vitamin E), phenolic compounds, and sometimes carotenoids. Tocopherols act as chain-breaking antioxidants, neutralizing free radicals and slowing down the oxidative chain reaction.
The stability of an oil is determined by several key factors:
- its fatty acid profile (PUFAs vs. MUFAs/SFAs)
- the presence of natural antioxidant fractions
- packaging (such as amber glass), exposure to oxygen, and temperature
- the duration of storage and general storage conditions
As a result, two batches of the same oil can vary in stability depending on their specific origin, extraction method, and processing.
9) Interaction with stratum corneum lamellae – why context is everything
The intercellular lipids in the stratum corneum are organized into lamellar sheets (lipid lamellae). These consist primarily of ceramides, cholesterol, and free fatty acids in precise ratios. Triglycerides from botanical oils largely remain on the skin's surface, though a small fraction can be hydrolyzed into free fatty acids via enzymatic pathways.
The impact of these free fatty acids on the skin barrier depends entirely on the context. A fatty acid that feels comfortable in small quantities can cause irritation in higher concentrations or on an already compromised skin barrier. This explains why the exact same oil can feel wonderful on one individual's skin but cause issues for another.
10) Cold-pressed versus refined – what changes chemically?
Cold pressing is a mechanical extraction process with minimal heat load. As a result, fatty acid ratios generally remain intact and micronutrients are often better preserved. Refining can neutralize smell and color, reduce free fatty acids and increase stability, but can also affect the phytosterol and tocopherol fraction.
From a chemical perspective, cold-pressed oils are not inherently "better"; they simply deliver a different active profile. The optimal choice depends on your specific goals (such as sensory quality, stability, or minimal processing) and individual skin conditions.
11) Translation to skin conditions – a chemical perspective
Linking fatty acid profiles to specific skin types requires nuance. Labeling skin as a single "type" is often an oversimplification; in practice, skin condition is highly dynamic and is influenced by barrier integrity, the microbiome, hormonal factors, environmental stressors, and daily routines.
Oily or acne-prone skin
In this context, research indicating a lower linoleic acid content in the sebum of individuals with acne-prone skin is highly relevant. Oils richer in linoleic acid are often experienced as lighter on the skin, but ensuring the stability of these PUFA-rich oils is critical. Oxidized by-products can cause irritation, particularly if the skin is already compromised.
Dry skin and barrier loss
Dry skin is commonly associated with elevated TEWL and a lipid deficiency. Botanical oils can reduce water loss through an occlusive effect while replenishing surface lipids. Note that occlusion is not the same as hydration: an oil does not introduce water, but it prevents existing water from evaporating. Comprehensive barrier support therefore also requires gentle cleansing and avoiding over-exfoliation.
Sensitive or reactive skin
When the skin barrier is disrupted, a high concentration of penetration-enhancing fatty acids can trigger sensitivity. Stability and simplicity are crucial here: fresh, well-stored oils and minimalist routines are highly recommended.
Mature skin
Mature skin often presents with both dryness and increased sensitivity. In this state, keeping the skin comfortable, stable, and gently supported is key. Natural antioxidants, such as tocopherols, can help limit the oxidative load on the skin's surface, though this is supportive and does not imply therapeutic claims.
For a practical overview per skin condition: Oil guide – finding the right oil for your skin type.
12) When botanical oils may be less suitable
A comprehensive approach also recognizes limitations. Situations where applying botanical oils may be less suitable include:
- during acute inflammatory breakouts where an occlusive layer feels uncomfortable
- when the oil has partially oxidized
- when combined with multiple highly active routines that already strain the barrier
- in cases of individual sensitivity to specific fatty acid profiles
Additionally, botanical oils are cosmetically supportive and do not replace professional dermatological treatment for medical skin conditions.
13) How to identify oil oxidation (Checklist)
- Odor – a rancid, sharp, or paint-like smell that deviates from normal
- Color – noticeable darkening or unusual cloudiness
- Texture – changes in viscosity or a stickier, heavier feel
- Skin feel – sudden irritation from an oil that your skin previously tolerated well
- Storage history – prolonged exposure to heat, light, or air
When in doubt, it is best to discontinue use, especially when dealing with PUFA-rich oils.
14) Frequently asked questions
Is an oil high in linoleic acid always better for acne-prone skin?
No. Fatty acid ratios are only one factor in a complex process. Product stability, your overall routine, skin barrier health, and individual tolerance play equally significant roles.
Are cold-pressed oils always better than refined oils?
Not necessarily. Cold-pressed oils typically retain more micronutrients, while refined oils can be more stable and neutral in scent. The optimal choice depends on your specific goals and skin condition.
Can oils repair the skin barrier?
Oils can support lipid replenishment and skin comfort, but barrier health depends on multiple factors, including gentle cleansing, irritation levels, lipid balance, and moisture retention.
Why does my oil smell different than it did initially?
This can be a sign of oxidation, especially in PUFA-rich oils. Check your storage conditions, ensure the bottle is tightly sealed, and limit exposure to heat and light.
What is the best way to store botanical oils?
Keep them in a cool, dark place, tightly sealed, and preferably in amber glass. Minimize exposure to air and avoid prolonged exposure to heat.
15) Conclusion
There is no single "best" oil. The suitability of a cold-pressed oil is closely tied to its fatty acid profile, oxidative stability, current skin condition, and freshness. By evaluating oils based on their molecular composition rather than marketing terminology, we can establish a nuanced, science-backed perspective on natural skincare.
Transparency and sources
Editorial note: This article is intended solely for educational purposes, providing biochemical and cosmetic context. It does not constitute medical advice and contains no therapeutic claims. For persistent or severe skin concerns, please consult a healthcare professional.
- Linoleic acid in sebum and acne context (review, PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC2943135/
- "Essential fatty acids and acne" (Downing, JAAD, 1986): https://www.sciencedirect.com/science/article/abs/pii/S019096228670025X
- Topical linoleic acid and microcomedones (Clin Exp Dermatol, 1998): https://academic.oup.com/ced/article/23/2/56/6627675
- Oleic acid and barrier function (PubMed): https://pubmed.ncbi.nlm.nih.gov/10620117/
- Plant oil components and stratum corneum lipids (PubMed): https://pubmed.ncbi.nlm.nih.gov/24372651/
- Squalene peroxidation and acne parameters (PMC, 2023): https://pmc.ncbi.nlm.nih.gov/articles/PMC10748031/
- Squalene oxidation and comedogenic/inflammatory context (Wiley): https://onlinelibrary.wiley.com/doi/10.1111/ics.12208
- Example: phytosterols and (thermal) processing of oils (PMC, 2024): https://pmc.ncbi.nlm.nih.gov/articles/PMC11311388/
Author: Vincent Meindertsma – More Natural
