Beyond Castor: Vegetable Oils That Regenerate Your Skin

Castor oil is very popular on social media, with enthusiastic advice to put it everywhere from your eyes to your vagina.

We did a main feature on it a little while ago, sorting out:

• what things does science actually say it’s good for,
• what things lack evidence, and
• what things go into the category of “wow definitely do not do that”?

Which body parts go into which category (according to the actual science) will probably surprise you: Castor Oil: All-Purpose Life-Changer, Or Snake Oil?

But what about other oils?

Time to get oiled up (but, correctly!)

Dr. Nina Poljšak and her research team were curious (as researchers often are), and investigated very closely (as in: under a microscope, not relying on nebulous before-and-after photos and hoping any difference was because of the oil) the effects of various oils and oil-constituting substances on the skin, specifically in the context of its regenerative ability.

Specifically, they tested the effects of seven vegetable oils (coconut, olive, linden, poppy, pomegranate, marigold, linseed) and their pure fatty acid or unsaponifiable components (unsaponifiable = you can’t make soap out of them; may seem a silly distinction here, but chemically speaking, it’s a useful way of sorting them, since the components that can’t be made into soap share certain properties, which are being looked at here), on skin’s keratinocytes and fibroblasts.

Even more specifically, they measured how each oil affects cell growth (proliferation) and cell movement (migration) in a wound‑healing test. The migration might sound like a strange thing to measure, but this is the means by which new skin cells replace old ones; in the human body, that means going from underneath to outside. They’re not just randomly going on tour or something (if they do, that’s cancer).

Here’s what they found!

The good:

• Poppy seed oil (high in linoleic acid) gave strong boosts to keratinocyte growth, especially at 0.1–0.15% concentration
• Marigold oil (high in calendic and linoleic acids) mildly improved growth of both cell types at similar doses
• Linden oil and linseed oils (especially high in essential fatty acids like linoleic and α‑linolenic acid) also promoted proliferation significantly

The bad:

• Olive oil (mostly oleic acid) slowed migration significantly and changed cell shapes
• Pomegranate seed oil (dominated by punicic acid) strongly inhibited both fibroblast and keratinocyte growth—even at low concentrations (0.01%)

The useless:

• Coconut oil (rich in lauric/myristic acids) showed no significant effect either way
• Unsaponifiable compounds were a mixed bag; some (such as β‑sitosterol or β‑carotene) helped keratinocyte growth; others (like squalene or ferulic acid) hindered fibroblasts; the conclusion the researchers drew here was that they add complexity but aren’t the main drivers of effects.

You can read the paper itself, here: Influence of vegetable oils and their constituents on in vitro human keratinocyte and fibroblast proliferation and migration

In summary…

If you’re looking for natural oils that gently boost skin cell renewal, go for oils high in linoleic acid—like poppy, marigold, linseed, or linden oils.

Skip the pomegranate seed oil (too inhibitory for regeneration in vitro), and be aware that oleic-rich oils like olive oil may cause subtle organizational effects in healing tissues, and slow the replacement of skin cells generally.

Olive oil is wonderful, but best kept to the kitchen: All About Olive Oil ← about its nutritional wonders and why it’s such a healthy oil

Want to learn more?

If you want an even simpler (not to mention: cheaper) approach:

“Slugging” Skin Care Routine (Tips From A Dermatologist)

Take care!