Castor Oil For Eyebrows: Does It Help Them Grow? Experts Weigh In + How To Use It

Take a peek at a few brow-growth serums, and you might notice a familiar ingredient etched on each label: castor oil. That's because this rich oil has been used for ages by beauty fans of many backgrounds, beloved for its moisturizing and antioxidant capabilities—some even swear the straight oil helps them grow full, luscious arches.

Castor oil is a vegetable oil extracted from castor beans. It has a notably high fatty-acid content (around 85 to 95% ricinoleic acid1, in fact), plus antioxidants and minerals aplenty. 

"Castor oil has documented1 anti-inflammatory2, anti-allergenic, antioxidant, antifungal, antimicrobial3, immune-boosting, and analgesic properties," integrative medicine physician Bindiya Gandhi, M.D., tells mbg about the health benefits of castor oil. The oil has long been used as a beauty staple for decades in both Ayurvedic traditions and Black households (read more about the anti-inflammatory, moisturizing oil here). 

Short answer? Maybe. "There's no published data showing that castor oil can help, but I do have the occasional patient who swears by it," notes board-certified dermatologist Whitney Bowe, M.D., about castor oil for hair growth. However not having published data to prove it works doesn’t mean that it doesn’t work, it just means that it simply hasn’t been studied at this time—and to be honest, few ingredients have robust data to support brow growth claims. So it’s not just castor oil that’s currently lacking in studies—it’s just not a well studied area of beauty at the moment. 

Even without clinical data, though, it makes sense why some do see success: Castor oil's antioxidant and fatty acid content feeds the delicate brow hairs with nutrients, which can help combat free radical damage and inflammation (and for what it’s worth: both are linked to hair aging4 and hair loss).

Castor oil is also incredibly moisturizing—it's both an emollient and an occlusive, which means it penetrates the strands with ease as well as seals in moisture. (This is also great news for your eyebrows, as moisturized brows do tend to grow fuller.) Keeping the strands happily doused in moisture is crucial for staving off hair loss as well, so even if the famed oil doesn't cause growth, per se, it can keep the wisps you do have healthy. 

However, you’ll see anecdotal evidence abound with castor oil. Lots of folks swear the ingredient spurs healthy hair growth on the scalp, lashes, or brows. Perhaps because "it depends on the length of the anagen (or growth) phase of your hair to begin with," board-certified dermatologist Jeanine Downie, M.D., previously told mbg. Meaning, those with a naturally longer brow-growth phase may see profound benefits from using castor oil. (And others may not see noticeable differences—that’s the challenging thing about anecdotal evidence, it’s entirely subjective.) 

Even if castor oil doesn't stimulate actual regrowth, it does coat your brow hairs with moisture—that alone is reason to dabble with the beauty staple. 

Remember: Dry, brittle strands (both on your head and brows) can lead to breakage5, which can ultimately hinder hair growth. 

Castor oil is a well tolerated ingredient to use on the skin. Of course, everybody is different and you should always consider your own unique sensitivities before applying any oil, ingredient or extract. We recommend patch testing formulas on the wrist prior to applying them on your face (where a reaction is much more noticeable). 

And of course, any product has the potential to backfire when used incorrectly. Specifically with castor oil, it should be used as a brow conditioner and rinsed off. Layering on oil after oil without proper removal has the potential to cause buildup. Buildup can suffocate the hair follicle, causing damage and even hair loss. While it would take repeated use over a long period of time to get to this point, it’s of course worth noting.