- Castor oil has not been proven to help eyelashes grow, but it may prevent them from falling out.
- This can still lead to the appearance of fuller lashes, since you may not lose as many lashes each day.
- Castor oil may also keep your lashes hydrated and control inflammation on your lash line caused by makeup.
- This article was medically reviewed by Debra Jaliman, MD, a board-certified dermatologist with a private practice in New York City.
Castor oil has become popular as a treatment to help eyelashes grow (it's Kardashian-approved), but research isn't super clear on its effectiveness. Here's what you need to know about the benefits of castor oil and whether it can actually lengthen your lashes.
What is castor oil?
Castor oil is derived from cold pressing the seeds of the castor plant. Most people know it as a natural supplement you can take to relieve constipation, but it has other health uses as well, including benefits for your skin.
"Castor oil is loaded with ricinoleic acid, a potent antioxidant that protects the skin from free radical damage that causes collagen damage and wrinkles," says Joshua Zeichner, MD, the director of cosmetic and clinical research at Mount Sinai Hospital.
In addition, the fatty acids in castor oil work to hydrate and soothe your skin from any irritation, Zeichner says. People also frequently use castor oil to encourage hair growth on their scalp, eyebrows, and eyelashes.
Castor oil for eyelashes: Is it effective?
"Castor oil is commonly used as a natural treatment for eyelash and eyebrow growth," Zeichner says. However, most of the evidence in favor of castor oil for hair growth is purely anecdotal.
The current research does suggest that some compounds in castor oil may prevent you from losing hair, rather than lead to a surge in hair growth. But preventing your lashes from falling out may lead to thicker lashes overall, since you won't lose as many hair follicles each day.
Specifically, castor oil is thought to help keep your lashes healthy in three different ways:
- Reducing PGD2. Ricinoleic acid, the main component of castor oil, may stop you from losing lashes by reducing your levels of prostaglandin D2 (PGD2), a type of fat that is linked to hair loss. A 2015 study found that in computer models, castor oil significantly decreased levels of PGD2, though it is unclear exactly what the effect is in humans.
- Controlling inflammation. Castor oil may be particularly helpful if you wear makeup on your eyelids or lashes because of the anti-inflammatory properties in ricinoleic acid. Cosmetics like mascara can cause inflammation on your lash line that may make your lashes fall out more easily.
- Keeping lashes hydrated. Castor oil may be able to boost the health of your current lashes by acting as a conditioner. "Because of its moisturizing benefits, castor oil can help condition and thicken the hairs themselves," Zeichner says.
How to use castor oil on your eyelashes safely
To use castor oil safely, you can buy a pre-diluted product, or mix a 1:1 ratio of castor oil with olive oil or peanut oil. The Cleveland Clinic also recommends using only organic castor oil when applying it to your hair or skin.
"Castor oil is commonly diluted out in a carrier oil before being applied to the skin," Zeichner says. A carrier oil is a neutral oil, usually a type of vegetable oil, used to dilute concentrated essential oils that may irritate your skin if they are used alone.
"Applying straight castor oil may lead to skin irritation, inflammation and dryness," Zeichner says. If you develop any red, itchy skin you should stop using it."
As with any skin product, it's best to first test the oil on a less sensitive area of skin like your arm and see how you react over the course of a few hours. As long as you don't react poorly, you can start using castor oil once or twice per day as needed, Zeichner says.
It's best to apply castor oil before bed to give it time to soak into your lashes. To apply castor oil, follow these steps:
The bottom line
Though more research is needed, castor oil may help to improve your eyelash health and prevent you from losing lashes. If you want to try using castor oil, make sure to dilute the oil and use it carefully. If you have any negative reaction to castor oil, stop using it immediately and contact your doctor.
Related articles from Health Reference:
- 6 causes of dark under-eye circles, according to a dermatologist
- The best anti-aging ingredients, according to dermatologists
- The best facial cleanser ingredients for each skin type, according to dermatologists
- 5 skincare benefits of vitamin C
- These are the best, most effective ingredients you should look for in a moisturizer
Madeline Kennedy Madeline Kennedy is a health writer for Insider covering a wide range of topics including reproductive and sexual health, mental health, nutrition, and infectious disease. Before joining Insider, Madeline worked as a health news writer for Reuters, and a domestic violence therapist. She has a master's degree in social work from UPenn and is interested in the intersection of health and social justice. Read more Read lessncG1vNJzZmivp6x7o8HSoqWeq6Oeu7S1w56pZ5ufonyowcidnKxnkpqutsDYaJqaq6Skv267yKVkn6eiYrK6scuaqqGdow%3D%3D