Does Castor Oil Really Help Lashes Grow? We Asked Derms to Weigh In

While some of us are lucky enough to be born with camera-ready lashes, many of us turn to growth-inducing serums, supplements, and ingredients to enhance our lash line. Castor oil, in particular, is commonly included in lash growth recommendations because of its anecdotal ability to influence hair and eyebrow growth.

However, while castor oil is commonly used on the scalp and brows, extra precautions need to be taken when applying it near the eye area. To understand castor oil's potential benefits and risks for lashes, we turned to two dermatologists and an oculoplastic surgeon for their expertise. Keep reading to find out the truth about using castor oil to help lashes grow.

What Is Castor Oil?

"Castor oil is a super versatile treatment for a whole host of ailments and has historically been used in a range of cultures as a natural skin fix," Ziering says. Castor oil is produced by pressing the seeds of the castor oil plant, which is typically exported from India. Castor oil is essential to the global specialty chemical industry because it is the only commercial source of hydroxylated fatty acid. "It is rich in ricinoleic acid, a fatty acid that can help moisturize the skin," Marcus explains. Ziering agrees, adding, "High levels of ricinoleic acid and other essential fatty acids in the oil extracted from the plant encourage detoxification."

To understand what benefits castor oil might have for eyelashes, it's important to understand how it interacts with the skin and hair. Marcus shares that castor oil acts as an emollient, which helps prevent water evaporation from the skin. "Castor oil's fatty acids are natural humectants, substances used to moisturize the skin by preventing water loss. This effect can promote good skin health, relieve dryness, support structure and soothe skin inflammation," Ziering explains.

Does Castor Oil Help Lashes Grow?

"The answer is no as far as triggering actual new growth," Ziering shares. "Although castor oil may help hydrate your lashes and decrease the risk of breakage, unfortunately, it will not cause lashes to grow any faster or denser than normal," Marcus adds.

Ziering goes on to say that there is not much (if any) actual scientific or clinical data on if castor oil helps to galvanize growth or activate the metabolic functions in the follicle to solicit the anagen or prolong the growth phase. Previous research on rabbits indicated that castor oil might affect hair regeneration. However, in humans, only one study determined that the ricinoleic acid in the oil penetrates the skin and acts as an inhibitor of prostaglandin D2 synthase (PGD2), which is believed to be a cause of androgenetic alopecia.

While castor oil may not directly initiate new lash growth, all three of our experts agree that castor oil may indirectly influence growth by improving the environment for growth and the health of your current lashes. "Castor oil has high levels of terpenoids and a tocopherol-related compound, glycerol which combine with fatty acids for healing and health of skin and will also help with the health of existing lashes," explains Douglas. In fact, castor oil has several properties that benefit the lashes, which may make it a great addition to your current beauty routine:

• Deeply hydrating: Castor oil is rich in ricinoleic acid, which is a fatty acid that can help moisturize the skin, explains Marcus. Douglas says these fatty acids can benefit the health and healing of the skin and lashes.
• Prevents transepidermal water loss: Castor oil acts as an emollient, which helps prevent water evaporation from the skin, Marcus says. Douglas agrees that castor oil coats to seal in moisture, and Ziering says this can help to preserve, protect and project better growth in lashes.
  
• Prevents breakage: "Eyelashes are often neglected," Ziering explains. "Dehydrated keratin protein is subjected to weakness and breakage, making lashes look lackluster, shorter, and thinner." Castor oil helps seal in moisture, which Douglas says will help you maintain more luscious-looking lashes. He adds castor oil can also help to boost the tear film and protect eyes from becoming too dry, which is beneficial in and of itself. "Dry eyes often result in rubbing, which can damage the delicate lashes or encourage breakage or early release from the follicle," Douglas notes.
• Antimicrobial and anti-inflammatory properties: Douglas shares that castor oil offers antimicrobial and anti-inflammatory properties. Research has supported the germicidal and fungicidal effects of castor oil, as the ricin and ricinoleic acid present in the oil protect the scalp and the shaft of the hair from fungal and microbial infections.

Is it Safe to Use Castor Oil on Lashes?

Douglas says castor oil is generally eye safe when a small amount is applied. "Castor oil is an occlusive product with a high density and viscosity which has its issues for eyes and skin, but it is often found in beauty products," " he explains. "In some instances, it can be used alone on the hair and skin with success." He does caution that it can clog or block follicles or pores but says this is generally unlikely when small amounts are used on the lashes. 

When it comes to side effects, both Marcus and Ziering say skin reactions like itching, swelling, and redness are possible. Ziering recommends patch testing a small amount behind the ear, on the upper lid close to the brow, or by the hairline before applying to your lash line. Douglas says you may also experience temporary blurred vision if a lot of castor oil enters your eye. "This will not last long—a few minutes to about 15 [at most]," Douglas explains.

To avoid any preventable issues, Douglas says to use clean hands or a clean applicator. It is also important to use a castor oil product that hasn't expired or shows signs of turning. "Normally, castor oil has a shelf-life of about one year," Douglas notes. "Cold-pressed castor oil can last longer [2-4 years] when sealed and stored properly. It is only recommended to store this ingredient in a cool, dry place. A kitchen, pantry, or shelf with temperatures around 65-70 degrees is ideal. Any change in color, consistency, or smell is a sign of compromise and should be thrown out and not used on or near eyes or skin."

How to Apply It

Ziering says castor oil should be applied nightly for best results. Douglas and Marcus recommend using a disposable or single-use mascara wand or eyeliner brush to apply the castor oil to avoid contamination. Douglas provided the following step-by-step guide for castor oil application:

1. Dip your chosen applicator into the castor oil and carefully apply it on your upper and lower lash line, coating each lash thoroughly while doing your best to avoid entry into the eye area at the waterline. 
2. Leave the oil on overnight as you sleep.
3. Remove the oil the following day in the shower, or wash your face with eye-safe micellar water.
   

The Final Takeaway

Castor oil is an intensely hydrating oil widely believed to influence hair growth. While our experts say castor oil has not been proven to cause new eyelash growth directly, all agree that the oil can benefit the appearance and health of your lashes. Castor oil will help maintain thickness, darker color, and hair strength, and a dense appearance. TLDR: It's worth trying along your pursuit of lush lashes.