Castor oil benefits: what it can and cannot do for hair, skin and lashes
Castor oil benefits explained: the evidence for hair growth, lashes, brows and skin, how to use it, hair felting and other risks, and why not to drink it.
The short answer
Castor oil can add shine and seal in moisture for hair, lips and dry skin. There is no good human evidence that it regrows hair, lashes or brows. Rarely, its thickness has caused irreversible hair felting; dilute and use sparingly.
- Keep it out of your eyes, patch test, and do not drink it for wellness.
Castor oil is a thick, pale oil pressed from castor beans, and its benefits for hair, lashes and skin are among the most shared beauty tips online. It can make hair look shinier and help seal in moisture, but the evidence that it regrows hair, lashes or brows is weak. It is also very sticky, and in rare cases has caused hair to mat beyond repair. Here is what castor oil can and cannot do, how to use it, and the risks.
General information, not medical advice. For hair loss, see a dermatologist; castor oil is not a proven treatment. Do not drink castor oil without a doctor's advice.
What is castor oil?
Castor oil comes from the seeds of the castor plant, Ricinus communis. Its main fatty acid, ricinoleic acid, makes it unusually thick. It has a long history in traditional medicine and cosmetics and is found in many lip products, balms and hair treatments.
What does the research say?
A 2026 narrative review of castor oil in dermatology found evidence that it can improve hair luster and noted a possible role in pattern hair loss through effects on a scalp compound called prostaglandin D2. The review also described benefits for skin hydration and elasticity, and its use in formulas to help other ingredients penetrate. But the authors called for more clinical research to establish how well it works, and the hair-growth idea has not been proven in good human trials.
| Claim | What the evidence suggests |
|---|---|
| Shinier, smoother hair | Supported: it can improve luster and seal moisture |
| Regrows hair | Not proven in good human trials |
| Longer lashes and fuller brows | No good evidence it grows new hairs; may condition existing ones |
| Hydrates skin | Some support as an occlusive moisturizer |
| Detox or weight loss when swallowed | No; it is a strong laxative |
Based on Girdler et al. 2026 and general dermatology guidance.
Castor oil for hair
As a pre-wash treatment or a few drops on dry ends, castor oil can make hair look glossier and feel less brittle. It is so thick that most people mix it with a lighter oil such as jojoba or argan. If you are worried about thinning, see our guide to minoxidil for women, the treatment with real evidence for female pattern hair loss.
The hair felting risk
Acute hair felting is a rare condition in which hair suddenly twists into a hard, tangled mass that cannot be combed out. A 2017 case report in the International Journal of Trichology described a woman whose long hair matted immediately after an oil bath with coconut and castor oil; the authors linked it to castor oil's high viscosity and long hair, and the hair had to be cut off. It is rare, but it is a reason to use castor oil sparingly, dilute it, and avoid vigorous rubbing and piling hair on top of the head while oiled.
Castor oil for eyelashes and eyebrows
- Evidence: no good studies show it grows new lashes or brow hairs, though it may condition existing ones.
- Eye safety: keep it out of your eyes; it can cause irritation and blurred vision.
- How: if you try it, use a clean spoolie with a tiny amount on the brows, or the very base of the upper lashes, and stop if you notice redness or swelling.
- Proven option: a prescription lash serum is the treatment with clinical evidence for longer lashes; ask a doctor.
Castor oil for skin
As an occlusive, castor oil can help seal moisture into dry lips, cuticles and rough patches. The review notes that contact dermatitis, an itchy allergic rash, has been reported, although rarely. On the face, it may feel heavy, and some people break out. Patch test on your inner arm first. Our guides to peptides for skin and Korean skin care cover gentler ways to hydrate.
How to use castor oil safely
- Choose a cold-pressed, hexane-free oil from a reputable brand.
- Patch test on the inner arm for a day or two.
- Dilute it with a lighter oil for hair and skin.
- Use small amounts: a few drops for ends, a thin layer for lips and cuticles.
- Wash it out gently, shampooing twice if needed, and avoid rough rubbing.
- Keep it away from your eyes.
Should you drink castor oil?
No, not for wellness. Castor oil is a strong stimulant laxative that can cause cramping, diarrhea and dehydration. It is sometimes mentioned for starting labor, but that should only ever be discussed with your doctor or midwife. For gentler digestive support, see our guides to fiber supplements and gut health.
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Questions people ask about this
Does castor oil make hair grow?
There is no good human evidence that it regrows hair. It can improve shine and seal in moisture. For hair loss, see a dermatologist.
Does castor oil grow eyelashes?
No good studies show it grows new lashes. It may condition existing ones. Keep it out of your eyes, and stop if irritation develops.
Is castor oil good for your skin?
It can seal moisture into dry lips, cuticles and rough patches. It may feel heavy on the face and rarely causes allergic rashes; patch test first.
Can castor oil damage hair?
Rarely, it has been linked to acute hair felting, where long hair suddenly mats and must be cut off. Use small, diluted amounts and avoid rough rubbing.
How do you use castor oil on hair?
Mix a little with a lighter oil, apply to the ends or as a pre-wash treatment, then shampoo it out gently.
Is it safe to drink castor oil?
Not for wellness. It is a strong laxative that can cause cramps, diarrhea and dehydration. Only take it on a doctor's advice.
