So here’s the thing: Technically, there aren’t any clinical studies to back up any castor oil claims. But as board-certified dermatologist Ava Shamban, M.D., founder of SKINFIVE, tells mbg, “There is no denying its anecdotal powers and prowess.” Specifically, it’s been a staple in both Ayurvedic and Black households for years, beloved by beauty fans aplenty for its many moisturizing and antioxidant capabilities.
Though the actual clinical evidence is lacking, there is scientific weight behind the ingredient itself: Castor oil’s main compound is ricinoleic acid, a fatty acid that has antioxidant and anti-inflammatory properties. The oil also contains vitamin E, which can also help protect those hairs from environmental aggressors. And, finally, it’s both an emollient and an occlusive—meaning, it’s able to penetrate into the strands and keep moisture from seeping out. “It is super hydrating so lashes don’t become brittle and dry or break, which happens as we age,” Shamban notes.
Ultimately, it’s the same conversation as castor oil for hair growth: Some swear by it; others simply don’t see the hype. That may be because “it depends on the length of your anagen (or growth) phase of your hair to begin with,” explains board-certified dermatologist Jeanine Downie, M.D. (That’s why some FDA-approved lash serums work by actually extending the growth phase of hair.) In other words, people with a naturally longer growth phase may see profound benefits from using castor oil—others, not so much.
But for what it’s worth: Even if castor oil doesn’t promote lash growth, per se, its nourishing compounds can certainly keep the flutters you do have healthy and thriving.