Does Castor Oil Really Work for Brow Growth? Experts Say Maybe—If You Do This

Castor oil: Some swear it's Miracle-Gro for brows, while others aren't so impressed. Both camps remain equally fervent in their position, so what's the real story here? Well, the very short answer is that everyone's skin, hair, nails, etc., are different, so of course, no one would achieve the exact same results with one hero ingredient. Still, castor oil has received such hype from myriad success stories that it's worth looking into its strong claims. One TikTok user even considers it directly responsible for their "eyebrow glow-up."

I sent trusted experts—board-certified dermatologist Hadley King, MD, and my personal brow wizard Joey Healy—all of my castor-oil questions to suss out its standing as a brow-growth MVP. Let's put this debate to bed once and for all, shall we?

What is castor oil?

Castor oil is a natural oil derived from the seeds of the—you guessed it—castor plant, which is native to India and Africa. The seeds from the plant are cold-pressed in order to extract the oil and its accompanying vitamins, minerals, and fatty acids. Castor oil has been used for thousands of years for its healing properties with roots in ancient Egypt, and it's been a big staple in many Jamaican households as well. Although, Jamaican castor oil is processed a little differently.

Benefits for Brows

• Very moisturizing: "I find that castor oil is helpful for brows as a deep conditioner," says Healy. "It is full of nourishing ingredients," namely fatty acids and vitamin E.
• Rich in antioxidants: Castor oil is brimming with vitamin E, an antioxidant that can protect the hairs against pesky free radicals, which are the source of age-related hair loss. If your brows appear thin due to natural aging as opposed to overplucking, antioxidants like vitamin E can help keep them from becoming sparser.
• Improves shine: "Castor oil has been shown in a study to increase hair luster," notes King. Shiny brows might not be first on your list of priorities, but trust that glossy, well-moisturized hairs can make your arches appear much thicker.
• Conditions brows: Given castor oil's rich fatty acid and antioxidant content, it can soften the brow hairs and make them more pliable, which means they're less likely to break.
• Strengthens hair: "If your brows are weak, frail, thin, fragile, and quick to break, I do think it can strengthen the quality of the hair, which can help you retain more," notes Healy.

Can castor oil help regrow brows?

Here's the thing. There are no clinical studies at the moment that can back up castor oil's hair-growth claims. That being said, the nutrients that make up castor oil do carry some scientific weight.

For example, ricinoleic acid (one of the main fatty acids in castor oil) has been shown to be super nourishing for the hair. According to King, the fatty acid can activate prostaglandin receptors in vitro (translation: in cell studies, not in humans). "We know that prostaglandin analogs can be helpful for hair growth (Latisse!), so this could be a possible mechanism of action," she says.

Castor oil is also super moisturizing for the brow hairs, and as a general rule, healthy, well-hydrated hair tends to grow faster. "If your existing brow hairs are shinier and healthier, they do appear thicker," says Healy.

We also can't ignore the flood of personal accounts that swear it's a brow-growth game changer. When crowds of people back a certain ingredient, especially one with a rich historical context, that may be enough proof to consider it! It certainly can't hurt to send your brows some extra TLC as long as you know the correct application methods, which brings me to my next point.

How to Apply Castor Oil Correctly

You can use castor oil whenever you please, but Healy says most people should apply it during their nighttime routine. "It's actually thicker than people think," he notes. "It's kind of gelatinous." That said, it might be best to use castor oil right before bed so the oil can soak into your brow hairs overnight. Also, make sure your brows are clean and dry before reaching for the castor oil.

Healy recommends saturating a cotton swab with the oil before applying it to the brow and massaging it into the base. Otherwise, the oil will merely sit atop the strands, so it might not work as well. "Just use a light amount," he adds. "I think a [cotton swab] is probably the best way to control that."

Again, castor oil is pretty thick, so it can be potentially pore-clogging if you use too much. If you have acne-prone skin, another oil might be better to use in general. It could also migrate into your eye if you use a huge glob, and no one wants that. A small dab with your cotton swab should be more than enough, especially if you use it nightly. "That's the run-of-the-mill [cadence] for anything that you're using for brow growth," Healy adds.

Alternatives for Brow Growth

If you can't use castor oil for any reason—say, it's too thick for your liking—or you just want to dabble in other brow-enhancing ingredients, know that you have options. Below, find recommendations from both Healy and King.

• Peptides: "Peptides are what really make brows grow," says Healy, who features the ingredient in his own Brow Renovation Serum. "Peptides are long chains of amino acids, and when peptides get together in their own long chains, they create proteins. Proteins really are the building blocks of brows."
• Rosemary oil: Of all the natural oils for hair growth, rosemary is arguably a dermatologist favorite. It's anti-inflammatory, antimicrobial, and brimming with antioxidants. "A 2015 study compared rosemary oil to minoxidil [aka the active ingredient in Rogaine] for hair growth, and at six months, both groups saw significant increases in hair growth," notes King.
• Jojoba oil: Jojoba has conditioning and strengthening benefits for the hair, similar to castor oil. It's also way thinner in consistency if you're looking for a lightweight oil to nourish your brows.
• Coconut oil: "It does not directly affect hair growth, but it may provide benefits that improve the health of the hair overall," notes King. "Because of its emollient properties, it may reduce hair breakage and make the hair less brittle. This may indirectly contribute to longer hair, as less breakage may result in longer strands over time."
• Tea tree oil: Healy is also quick to call out tea tree's anti-inflammatory and antibacterial properties. "All of that stuff creates a really great, clean brow," he says. "It can help to nourish the brow through all of those properties, but it's also very healing."

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