Lipids are the oils and fats that make up and reinforce your skin barrier. They fall into emollients that soften, occlusives that seal in water, and barrier-identical lipids like ceramides that rebuild what the barrier is actually made of. They fix dryness at the structural level rather than just adding water.
Understanding the three roles clears up a lot. Emollients (squalane, jojoba, shea) fill gaps between skin cells to smooth and soften. Occlusives (petrolatum, dimethicone, castor oil) form a surface layer that dramatically slows water loss. Ceramides are the star: they are the same lipids your barrier uses, so they repair rather than just coat.
Dry versus dehydrated matters here. Dehydrated skin lacks water and wants humectants; truly dry skin lacks oil and wants these lipids. Most barrier-repair routines pair a humectant (to attract water) with a lipid or occlusive (to keep it in) — which is why ceramides and hyaluronic acid are such a common, effective duo.
Every lipid we cover, with what it does and the concerns it is most often used for. Each name links to its full glossary entry.
| Ingredient | What it is | Most used for |
|---|---|---|
| Ceramides | Lipids constituting ~50% of the stratum corneum intercellular matrix. | Dryness, Redness, Aging |
| Squalane | A saturated, stable form of squalene — a skin lipid that declines dramatically after age 30. | Dryness, Aging |
| Linoleic Acid | An essential omega-6 fatty acid critical for ceramide production. | Acne, Dryness |
| Shea Butter | Extracted from the African shea tree nut. | Dryness, Redness |
| Jojoba Oil | Technically a liquid wax rather than a triglyceride oil — composed primarily of long-chain wax esters structurally similar to human sebum. | Dryness, Oiliness |
| Dimethicone | A synthetic silicone polymer used as a skin protectant, occlusive and texture enhancer. | Dryness, Texture |
| Petrolatum | One of the most effective occlusives in existence — reduces TEWL by up to 98%, more than any other commonly used skincare ingredient. | Dryness, Redness |
| Castor Oil | A thick oil cold-pressed from Ricinus communis seeds, defined by an unusually high ricinoleic acid content (~90% of its fatty acids) that gives it its tackiness and mild anti-inflammatory activity. | Dryness, Redness |
Across the catalogue, the lipids here are most often used for these concerns — each links to its evidence-led concern hub with a full routine:
Dryness (8), Redness (4), Aging (2), Acne (1), Oiliness (1), Texture (1).
These commonly pair well with: Ceramides, Hyaluronic Acid, Panthenol, Squalane, Vitamin E, Niacinamide. Pairing is about getting more from a routine without adding irritation — humectants, barrier lipids and niacinamide are frequent partners here.
Nothing in this category carries a hard "avoid combining" flag in our catalogue — these are generally cooperative actives. Always introduce one new product at a time regardless.
Emollients (like squalane and jojoba oil) soften skin by filling the gaps between surface cells. Occlusives (like petrolatum and dimethicone) form a barrier on top that physically slows water loss. Many good moisturisers combine both — emollients for feel, occlusives to lock hydration in.
Yes — ceramides are among the best-evidenced barrier ingredients because they are identical to the lipids your skin already uses to hold itself together. Replacing them helps repair a compromised barrier rather than just masking dryness, which makes them especially valuable for dry, sensitive or over-exfoliated skin.
No — despite its reputation, cosmetic-grade petrolatum is one of the most effective and well-tolerated occlusives known, and it is non-comedogenic in its refined form. It reduces water loss dramatically and is a mainstay of barrier repair. The concerns usually stem from confusion with industrial-grade product, not the purified version in skincare.
Lighter, non-comedogenic oils high in linoleic acid — such as squalane and rosehip — tend to suit oily and acne-prone skin better than heavier, oleic-rich oils. That said, oils are optional; if you are breakout-prone, patch test and introduce one at a time rather than assuming any oil is safe.
Browse the rest of the ingredient library: Acids, Retinoids, Vitamins — or see the full ingredient categories index.
Written and reviewed by JoAnn, editor of Skin Stacker — see our methodology and editorial standards.
Reviewed / last updated: 2026-07-17. For informational purposes only — not a substitute for medical advice.