Does Castor Oil Grow Eyelashes?

Many clients ask whether castor oil can grow eyelashes or eyebrows. It’s a fair question: social media is full of before & after reels and beauty editors often list it as a “natural” fix. In this article I’ll explain what castor oil is, what it can realistically do for lash and brow health, what the evidence says about growth, how to use it safely if you choose to, and where clinically proven options fit in.

What is castor oil?

Castor oil is a thick, glossy oil pressed from the seeds of ricinus communis, a tropical plant native to Africa and now grown worldwide. It has been used for hundreds of years in traditional medicine, skincare, and even as a pharmaceutical ingredient thanks to its unique chemistry.

Its principal component is called ricinoleic acid which makes up around 85 to 90% of the oil. This fatty acid is unusual because it contains a hydroxyl group that makes it noticeably thick compared to other oils. This viscosity allows it to form a protective film over skin and hair, sealing in moisture and adding shine.

It’s important to note that this plant is the same the source of the potent toxin ricin, the purified oil contains no ricin and poses no such danger. The toxic proteins are water soluble and are completely removed during oil extraction and refining. What remains is a thick oil that is widely used.

From a safety perspective, castor oil and its derivatives (such as hydrogenated castor oil and PEG-castor oil esters) are considered non-toxic and non-sensitising when used in cosmetic formulations. This has been confirmed by multiple reviews, including the independent Cosmetic Ingredient Review (CIR) panel and European safety assessments.

What castor oil can do for lashes and brows

Condition & protect the hair

The thickness of castor oil reduces water loss from the hair shaft. In practice, this can make lashes/brows feel softer, look plumper, and could reduce breakage.

Soothe the eyelid margins

In some ophthalmological studies castor oil has been looked at for blepharitis and dry eye. They suggest that castor oil may improve symptoms when used appropriately. While not hair-growth studies, they show that it can be safely used around the eye.

Dr Tom Walker

Dr Tom Walker is one of the founders of Opti Laboratories, the successor to Mylash which he founded in 2007. He graduated from the University of Glasgow with a degree's in medicine and anatomy. His work has been featured in publications including The Times newspaper and Vogue magazine. He has a passion for bringing innovative and evidence based treatments to the market. The eyelash and eyebrow growth treatment he introduced is the only clinically proven growth treatment available.

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Does castor oil grow eyelashes or eyebrows?

At present, there are no robust human clinical trials demonstrating that castor oil increases eyelash or eyebrow growth, either by increasing the number of follicles or by stimulating the hair growth cycle.

The best related study is in the journal Dermatologic Therapy. In this multicentre cohort study involving 278 patients with alopecia areata three topical regimens were compared. The first was a steroid (betamethasone) by itself, the second was the same steroid with minoxidil, and the third regime was the steroid with castor oil and jojoba oil. The study found that the steroid & minoxidil combination produced significantly higher hair regrowth rates with a correspondingly better patient satisfaction, as well as a shorter period to improvement compared with the other two groups. By contrast, the steroid with castor oil & jojoba oil did not show superior outcomes compared with the steroid by itself.

An experts opinion

Castor oil may help your lashes and brows look a bit better by making them appear plumper and shinier due to the surface of the hair being coated in the oil. There is no dependable studies that prove that it stimulates new growth or accelerates the hair cycle in eyelashes or eyebrows. If you want a treatment with proven eyelash and eyebrow growth efficacy then a prescription strength growth treatment is the gold standard. These treatments have multiple randomised clinical trials behind them.

Reference:

Muntz, A., Lacey, M., & Craig, J. P. (2021). Topical periocular castor oil for blepharitis and meibomian gland dysfunction: A randomised, double‐masked, pilot study. Clinical and Experimental Optometry, 104(3), 315–322. https://pubmed.ncbi.nlm.nih.gov/33037703/
Al-Zahrani, A. M. (2021). The effectiveness and safety of three treatment regimens of topical minoxidil 5.0%, betamethasone 0.064% w/w, and castor and jojoba oils for alopecia areata: A multicenter cohort study. Dermatologic Therapy, 34(6), e15161. https://onlinelibrary.wiley.com/doi/full/10.1155/dth/6631359
Kporou, K. E., Adjé, K. B., Koffi, C., & Konan, K. M. (2021). Quality, safety and activity of an ointment formulated from Butyrospermum parkii and Ricinus communis oils on rabbits’ hair growth. Revue RAMReS – Série Pharm. Méd. Trad. Afr., 20(1), 38–46. https://www.researchgate.net/publication/355890691_Quality_safety_and_activity_of_an_ointment_formulated_from_Butyrospermum_parkii_and_Ricinus_communis_oils_on_rabbits_hair_growth
Cosmetic Ingredient Review Expert Panel. (2017). *Final Report on the Safety Assessment of *Ricinus communis (Castor) Seed Oil, Hydrogenated Castor Oil, and Related Ingredients. Cosmetic Ingredient Review (CIR). https://www.cir-safety.org/sites/default/files/Castor%20Oil.pdf

These are before and after photos of real Opti Laboratories customers.

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