But Really, Though: Can Castor Oil Help Your Lashes Grow Longer? Derms Weigh In

We've discussed castor oil's effects on hair growth in general, as well as whether it can help sprout lush, full brows. Here comes the natural next step: What about castor oil for lashes? Those tiny hairs are, well, hairs, so they must respond to the ultra-moisturizing oil in a similar fashion. Right? 

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 the 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.

Browse through the wide selection of lash serums out there, and you'll likely find more than a few include the star oil in their ingredient lists. Efficacy-wise, there isn't much of a difference between using straight castor oil and those castor-oil-infused serums. The only difference is that the lash serums probably lend a more appealing application. Castor oil itself can be quite thick in consistency (especially Jamaican black castor oil, where the castor beans are roasted and boiled before the extraction process), which can feel a bit goopy and heavy on the lash line. 

First things first: If you're using castor oil on lashes, it should be the very last step in your nighttime skin care routine (yes, even after eye cream, if you use one). 

Of course, you'll want to remove any and all makeup beforehand, so your lids don't have any lingering product that could block the oil. Although, Shamban says you might not want to use an oil-based remover: "It may leave an oil coating on the lashes and preclude the castor oil from being applied directly on the lashes and lash line." (Check out these other natural makeup remover options, some of which are oil-free.)