Face oils are often celebrated for their ability to promote skin glow, softness, and nourishment — but not all oils age gracefully. When certain oils oxidize or go rancid, they don’t just lose effectiveness. They can actively harm the skin, especially sensitive or rosacea-prone complexions.
Understanding how rancidity happens — and how to avoid it — is essential to maintaining a calm, stable barrier. Here’s what actually happens when oils break down.
What Does It Mean When an Oil “Goes Rancid”?
Rancidity is the process where oils degrade due to oxidation, light, heat, and exposure to air. The result is:
- A sour or “off” smell
- A change in color
- A sticky or tacky texture
- Loss of beneficial nutrients
- Formation of oxidized fatty acids, peroxides, and free radicals
These byproducts don’t just smell unpleasant — they interact with the skin in very real, very damaging ways.
Why Do Some Oils Go Rancid Faster?
Not all oils have the same stability. Oils high in polyunsaturated fatty acids (PUFAs) break down the fastest.
Oils most prone to rancidity include:
- Rosehip oil
- Chia seed oil
- Hemp seed oil
- Evening primrose oil
- Grapeseed oil
These oils oxidize quickly, especially when:
- Stored in clear glass
- Exposed to sunlight
- Repeatedly opened
- Formulated without antioxidants like Vitamin E or ROE
- This is why so many “natural” oils quietly spoil long before the bottle is empty.
The Hidden Effects of Rancid Oils on Skin
This is the part most brands won’t say — because it reveals why so many face oils irritate sensitive skin.
1. Increased Irritation + Sensitivity
Oxidized oils produce lipid peroxides — molecules that trigger inflammation.
On the skin, this can lead to:
Redness
Stinging
Tingling
Burning sensations
Flare-ups for rosacea and eczema
These reactions often get misdiagnosed as “purging” or sensitivity to actives, when the real culprit is rancidity.
2. Barrier Breakdown
Healthy skin depends on stable lipids.
Rancid oils:
Disrupt the lipid matrix
Increase transepidermal water loss (TEWL)
Weaken barrier integrity
Leave skin vulnerable to environmental irritants
In short: unstable oils create unstable skin.
3. Accelerated Aging
Oxidized oils generate free radicals — the same type of stressors responsible for premature aging.
This can contribute to:
Loss of firmness
Dullness
Increased fine lines
Slower healing
Uneven texture
Fresh oils support repair. Rancid oils accelerate damage.
4. Breakouts + Congestion
As oils oxidize, their fatty acid profile changes.
This can lead to:
Blocked pores
Clogged follicles
Inflammatory acne
Rough texture
Even oils marketed as “non-comedogenic” can cause issues once oxidized.
Why Léonie Avoids Rancidity By Design
Léonie was formulated specifically to resist oxidation and remain stable from the first drop to the last.
This is achieved through:
✔ Ultra-stable base oils
Squalane (fully saturated + oxidation-resistant)
Jojoba Seed Oil (a liquid wax, not a fragile oil)
Jojoba Esters (even more stable than jojoba itself)
Camellia Seed Oil (naturally antioxidant-rich)
✔ Low percentages of delicate oils
Amaranth, black raspberry, and botanical extracts are used sparingly — enough for benefit, never enough to destabilize.
✔ Built-in antioxidant system
Vitamin E (mixed tocopherols)
Rosemary Oleoresin Extract
Natural antioxidants from sterols and seed oils
✔ Protective dark-glass packaging
Light-blocking. Air-minimizing. Freshness-preserving.
A stable formula = a stable complexion.
**The Takeaway:
Fresh Oils Support the Skin. Rancid Oils Stress It.**
Most irritation blamed on “actives” or “sensitive skin” is actually the result of unstable, oxidized oils.
Choosing stable lipids isn’t just about shelf life — it’s about protecting the barrier, calming inflammation, and preserving long-term skin health.
Léonie was created for exactly this purpose:
to give you an oil that stays fresh, gentle, and skin-identical — never rancid, never reactive.