What happens when you put castor oil on your eyelashes every day?

Vaseline. Growth serum. Castor oil? This vegetable oil, arguably most commonly known as a simple laxative but generally used for many different purposes including treating acne and other skin inflammation as well as wrinkles and age spots, is also supposedly a little-known beauty go-to for growing your eyelashes thicker, fuller, and longer. 

According to Healthline, castor oil is actually a common ingredient in several of our most-used beauty products due to its naturally hydrating properties. Unlike other ingredients, the oil doesn't clog pores or irritate skin either, so when it comes to natural remedies, it's safer than many others. There are plenty of common eyelash mistakes, but is not using castor oil one of them?

How do you use castor oil on your eyelashes?

First and most importantly, if you are considering utilizing castor oil for eyelash growth on a daily basis, make sure that what you buy is pure castor oil. If it's been blended with other ingredients, it could irritate your skin or have zero effect whatsoever, leaving you with greasy eyelashes for no reason. Cold-pressed castor oil, which is clear, and Jamaican black castor oil (which is actually brown, rather than black) are the two most commonly used for at-home beauty practices. 

The latter is generally the preferred choice, but both variations contain the same basic properties. You'll need to do a swatch the day before on your arm to check for any irritation before applying to your eyelashes. The best time to use castor oil on eyelashes is before bed, when your eyes are clean and completely free of makeup. Apply a small amount using a cotton swab along the top of your lash line, ensuring none gets in your eyes (if any does, wash thoroughly). Wash it off in the morning.

Does castor oil really help eyelash growth? Maybe, maybe not

Although no scientific studies have been conducted yet in relation to castor oil and eyelash growth, evidence suggests ricinoleic acid, which makes up nearly 90 percent of it, may help to reduce or even reverse hair loss. Dominic Burg, Ph.D., hair biologist and chief scientist for Évolis Professional, told Byrdie, "Castor oil contains ricinoleic acid as its main component, which is thought to work through stimulating the receptor of a special molecule called prostaglandin E2 (PGE2), which has diverse effects on the body including dilation of the blood vessels, uterine contractions, and bowel activity. The theory is that PGE2 also has a role in hair growth by stimulating hair follicles to enter the growth phase."

However, it's worth noting cosmetic chemist and author Perry Romanowski emphatically told Allure, "Castor oil will not grow hair. There is no evidence for it and no scientific theory supporting that it would work, so yes, it's a total myth." 

So, there's good reason to believe slathering it on your eyelashes every day will do absolutely nothing. If you're still curious, castor oil is cheap, easy to use, and generally safe as long as you take pains to avoid getting it into your eye. It could be worth a try provided a swatch doesn't show any obvious irritation from it.