Every few months a new "grandma remedy" goes viral in the beauty corner of the internet, and right now it's castor oil — dabbed on lash lines, swiped across brow bones, and in some videos, applied straight into the eye itself. The promises are big: longer lashes, clearer eyes, less irritation. So I want to walk through what's actually been studied here, because the honest answer is more nuanced than either the hype or the panic headlines suggest.
What castor oil actually does to lashes
Let's start with the claim everyone's chasing: does it make your eyelashes grow?
A comprehensive 2024 review of eyelash serum ingredients, published in the Journal of Cosmetic Dermatology, looked at the evidence behind castor oil and the many other non-prescription ingredients marketed for lash growth. The conclusion was clear: castor oil lacks adequate scientific evidence to substantiate claims of meaningful lash growth. There's no well-designed clinical trial showing it increases how many lashes you grow or speeds up the growth cycle.
What castor oil probably does do is condition the hair shaft. It's rich in ricinoleic acid, a fatty acid with humectant and mild anti-inflammatory properties, and coating lashes in it can make them look glossier, feel less brittle, and shed less from breakage. That's a real cosmetic effect — your lashes can look fuller because you're keeping more of the ones you already have, not because you're growing new ones. It's a meaningful difference if you're deciding whether it's worth the hype.
If you want an ingredient with actual evidence behind it for lash growth specifically, that's bimatoprost (sold as Latisse), the only FDA-approved prescription option, which works through a completely different mechanism and needs to be prescribed and monitored by an eye care provider. Using Latisse does come with its own risks that deserve a conversation with your eye care provider.
Why putting it in your eye is a different question
Here's where I get more cautious. A lot of the current trend videos go beyond the lash line and involve applying castor oil directly onto the eye's surface, sometimes marketed as a dry eye or "eye whitening" fix.
The 2023 TFOS Lifestyle Report on cosmetics and the ocular surface — a major consensus review from the Tear Film & Ocular Surface Society, the same group that sets international standards for dry eye care — specifically examined castor oil and other cosmetic oils used around the eyes. It's a useful ingredient in formulated, sterile eye products designed and tested for ocular use. It is a different thing entirely from applying a non-sterile, cosmetic-grade bottle of oil directly onto your eye at home.
The risks aren't hypothetical. Oils applied to the ocular surface can disrupt the tear film rather than help it, and non-sterile products carry a real risk of introducing bacteria to an environment that's normally very good at defending itself — until you compromise it. Reported complications from unsupervised ocular use of oils include irritation, blurred vision, allergic reactions, and in more serious cases, corneal infection.
What I'd actually tell a patient trying this
If you want to use castor oil as a lash conditioner, applying a small amount to clean, dry lashes at night — the way you'd apply a lash serum — carries relatively low risk for most people, aside from the small chance of an allergic reaction at the lid margin.
What I don't recommend is putting castor oil, or any non-sterile oil, directly onto the eye itself. If you're dealing with dry eye, gritty, or burning eyes, that's a symptom worth an actual evaluation, not a home remedy that hasn't been shown to fix the underlying cause.
If anything you put near your eyes causes persistent redness, pain, discharge, or blurred vision, stop using it and get seen. Those aren't symptoms to wait out.
Thinking about your eye health?
I see patients at Eye & Health in the East Village. If a viral trend has you second-guessing something you're already doing to your eyes, that's a completely reasonable reason to book a visit. You can book online — usually within the week.
This is not medical advice. Please consult your eyecare professional or schedule an eye appointment today.
