Based on the many TikTok videos I watched during my first session, the benefits of castor oil for hair growth are simply endless. The oil is actually used to make hair longer and thicker, especially in Jamaican beauty treatments, and as an ingredient in homemade hair mask recipes and DIY tutorials. “Castor oil is an affordable option if you want to add shine, tame frizz, and keep your hair looking smooth and silky,” says hairstylist and certified trichologist Courtney Foster. But why? Does it really make your hair grow faster?
Before you start slathering your hair with castor oil to boost growth, here’s what the pros have to say: Unfortunately, castor oil itself doesn’t promote hair growth (remember, other than minoxidil, the active ingredient in Rogaine, no topical product promotes hair growth!). But it can help lock in moisture in your scalp and hair ends, creating a healthy environment for optimal hair growth. I spoke to dermatologists and trichologists about the different ways castor oil can promote hair growth, including what it is, how it works, and how to properly use it at home to help your hair grow longer. Read on for more details.
Castor oil is a vegetable oil extracted from the seeds of the castor plant. It is usually colorless, but can be yellow or dark brown depending on how it is prepared. Jamaican black castor oil is one of the most popular varieties, with a thicker texture and a warm, toasty flavor due to being simmered with castor oil ash.
“Castor oil is rich in anti-inflammatory fatty acids, which improve circulation and may speed up the hair growth cycle,” says dermatologist Jessie Cheung, MD. Because of its fatty acid content, castor oil has a thick texture, but shockingly, it has a low comedogenic rating, so it’s less likely to clog your pores (but remember, clogged pores are very subjective and depend on individual skin type; what clogs my pores may not clog yours).
“It’s also rich in antioxidants and has antibacterial and antifungal properties,” adds Dr. Chang, making it an ideal oil for dry scalps and even dry hair. To get a little more scientific, “castor oil is a long-chain fatty acid,” says trichologist Bridget Hill, which means it can “supply hair follicles with protein and nutrients, and help prevent follicle inflammation.” But do these hair-friendly proteins actually promote hair growth? Keep reading.
Unfortunately, castor oil alone does not promote hair growth, says trichologist Shab Kaspara. While castor oil fans claim that it can “stimulate” hair follicles and “promote hair growth,” Hill notes that there are no studies or scientific proof that castor oil helps hair grow. In fact, no topical treatment can speed up hair growth or prevent hair loss on its own—only hormones, genetics, health, and age can do that, Hill explains. That’s why “hair growth requires a holistic approach” that includes healthy hair and scalp care habits.
Even if castor oil doesn’t promote hair growth, it can help retain moisture, soothe irritation, and create a healthier scalp, which in turn creates a more favorable environment for hair growth. So, if your goal is to grow long hair, there’s no reason not to use castor oil to help you succeed. Which brings me to…
All hair types can (and should!) use castor oil to add moisture and smoothness. However, how and how often to use castor oil depends on your hair type. Why? Caspara says that because castor oil is thick, if you have fine, thin, or low-porosity hair, it can clog follicles and make your roots greasy.
Below, we’ll break down how to use castor oil based on your hair type, but no matter how you use it, you should add a clarifying shampoo to your monthly routine (or weekly if you have an oily scalp) to help dissolve any product buildup that can occur with regular castor oil use.
How often you apply castor oil depends on your hair type. But in general, “there is no standard frequency for using castor oil,” says Bleicher, “but I recommend using it once or twice a week for at least three months, because that’s how long it usually takes for new hair to grow.”
There is no “best” oil for hair growth, as oil alone cannot promote hair growth. Remember: hair growth is a result of your DNA (primarily age, genetics, and hormones), so it’s difficult to control. Dermatologists typically recommend topical minoxidil or oral medications like spironolactone. But if you’re looking for a “natural” at-home method, hair oils can be a great way to lock in moisture in your scalp and potentially relieve inflammation and irritation—all of which can promote hair growth. Castor oil, rosemary oil, and peppermint oil are great anti-inflammatory oils that help reduce scalp inflammation, while coconut oil, argan oil, and shea butter act as powerful sealants to help lock in moisture and prevent moisture loss.
It’s worth noting that rosemary oil has also shown promising results in hair growth and hair loss studies (though more human studies are needed to prove it). Dr. Zhang cites a 2015 study that compared rosemary oil extract and minoxidil in men with hereditary androgenetic hair loss. It showed little difference in effectiveness after three and six months. Patients also note that rosemary oil reduces irritation and itching, as it has natural anti-inflammatory properties. Try applying a few drops of rosemary oil scalp serum daily to soothe your scalp and stimulate hair growth over time.
How long castor oil works on your hair depends on your hair type. People with fine to medium-coarse hair should apply castor oil to the midsection and ends of your hair and leave it in for 30 minutes before shampooing. For coarse, thick, or very dry hair, use castor oil as an overnight treatment or apply it to the ends as a leave-in conditioner. Hill’s tip: After massaging and applying castor oil, wrap your hair in a silk scarf to help the oil penetrate deeper (and add shine).
Dr. Chang noted that the only potential downside to using castor oil for hair growth is that it’s so heavy that it’s difficult to rinse off your scalp, which can lead to oil buildup, acne, and ultimately an oily scalp. “Castor oil is beneficial for all skin types because it has anti-inflammatory and antibacterial properties,” she says. “But be careful if you have sensitive or oily skin, as there have been reports that castor oil can cause contact dermatitis, and acne can worsen when you cleanse your skin.”
The biggest risk with castor oil for hair is the potential for scalp acne and buildup, as it has strong moisturizing and occlusive properties. To reduce the risk of acne, dermatologist Dr. Lily Talakoub recommends avoiding castor oil on the hairline and being especially careful when applying it before bed, as castor oil can transfer from your pillowcase to your face, which can lead to acne.
Hill explains that if your hair is already dehydrated, castor oil can make it even drier because it prevents excess moisture from penetrating into your hair. So to prevent your hair from accidentally drying out, be sure to moisturize it with a hair product rich in other moisturizing ingredients like shea butter, glycerin, and panthenol before applying castor oil. You can also incorporate castor oil into your deep conditioning routine (using a castor oil recipe or adding a few drops to your favorite conditioner) to keep your hair from looking dry.
And like all ingredients and products, castor oil can cause irritation and allergic reactions, so it is recommended to test on your neck before applying to your scalp, especially if you have sensitive skin. Castor oil, although rare, is better to be safe than sorry.
There is no right or wrong way to apply castor oil to your hair – some people prefer to leave it on overnight, while others prefer to massage it into their scalp. The best method for you will depend entirely on your hair type and problem areas. It is important to note that Jamaican black castor oil is thicker, so it is best for those with thick or coarse hair, while regular cold-pressed castor oil is great for fine hair. Here are a few things you can try:
Hairstylist Natasha Burrell likes to use castor oil to massage the scalp and condition the lengths of your hair. After massaging the castor oil into your scalp and ends for 5 to 10 minutes, Burrell recommends steaming your hair for 20 to 30 minutes to help the castor oil penetrate your scalp. Once you’re done, you can shower and wash your hair if you have fine/thin hair, or wait until your next wash if you have coarse, damaged, or dry hair.
If you have fine or medium-length hair that gets oily easily, apply castor oil from mid-lengths to ends and leave it on for 10 minutes before shampooing. If you have medium to thick hair, massage castor oil into roots and ends, leave it on for an hour (or overnight), then rinse. Hill also recommends using a blow-dry cap to help the castor oil penetrate your hair.
For a more personalized treatment, Burrell suggests mixing castor oil with another carrier oil, like jojoba or coconut oil, to dilute the castor oil and make it thinner, making it easier to work with even fine hair. On the other hand, if you want a more nourishing formula, you can mix castor oil with olive oil for a deep conditioning treatment (although never do this on fine or low-porosity hair).
If you have medium to thick hair that is prone to frizz, add a few drops of castor oil to your conditioner once or twice a week for a nourishing treatment that will leave your hair smoother and more hydrated.
Before going to bed, apply castor oil to your hair and put on a shower cap. When you wake up, gently comb your hair, take a shower, and wash with shampoo and conditioner. Note: If you want to completely remove the castor oil residue, you may need to wash your hair twice to thoroughly rinse it out.
For gentle scalp care, mix castor oil, olive oil, grapeseed oil, coconut oil, and vitamin E oil in an applicator bottle and apply the mixture every night before bed or whenever your scalp feels itchy or dry. Click on this tutorial to learn how to do it.
Before bed, dip a clean eyelash brush or cotton ball into a small amount of castor oil and gently rub it along the roots of your eyelashes, being careful not to let the oil get into your eyes. In the morning, wash your face with your regular cleanser to remove excess oil.
While castor oil won’t magically make your eyelashes or eyebrows grow, it can certainly have the opposite effect. According to celebrity eyelash extension expert Dionne Phillips, castor oil works well for removing eyelash extensions at home, as she previously told Cosmo magazine. Simply use the cotton swab technique described above to loosen the glue and remove the extensions while moisturizing your natural lashes.
Castor oil is safe to use on your eyelashes and eyebrows, as long as you don’t put it directly in your eyes. But remember: Castor oil isn’t guaranteed to make your eyelashes grow faster, though it can make a great eyelash serum. “Castor oil can hydrate your lashes and make them look thicker and shinier,” Eliza Haberman, MD, an ophthalmologist at NYU Langone Health, previously told Cosmo. “It can also help prevent lash breakage, thereby promoting healthier lash growth.”
Remember that the skin around your eyes is thinner and more susceptible to clogging, so “using castor oil around your eyes can aggravate milia, blackheads, and pimples,” says Dr. Talakoub. By the way, this works for all skin types, not just oily or acne-prone skin, so if you have particularly clogged pores and pimples, it’s best to approach this DIY remedy with caution.
Unfortunately, castor oil does not promote natural hair growth (only genetics and overall health can do that). But it is still extremely moisturizing, meaning it hydrates your scalp and hair, creating a great environment for stimulating hair growth. Be mindful of everyday habits that often contribute to hair loss and breakage, such as tight hairstyles (like braids and tight ponytails), vigorous brushing, and excessive heat styling. While castor oil does have moisturizing properties, its effects on hair growth are limited.
Beth Gillette is the Beauty Editor at Cosmopolitan magazine with over five years of experience researching, writing, and editing skin care articles covering everything from hair growth devices to Botox. She is an expert on all things hair care and is especially an expert on using castor oil for hair growth. She has tried dozens of hair growth products and ultimately achieved success in keeping her forever-long locks. She regularly tests and reviews the effectiveness of hair care products and collaborates with leading trichologists and hairstylists in the industry to evaluate new formulas and brands.
Brooke Shunatona is a staff writer for Cosmopolitan magazine with over a decade of experience writing about beauty, style, and lifestyle, including articles on microfiber towels and the best hair straighteners. She knew all about the benefits of castor oil for hair growth thanks to information, product reviews, and ratings provided by experts.
Beth Gillette is the beauty editor at Cosmopolitan, covering skincare, makeup, hair, nails, and more for both digital and print. You can usually find her with a bright eyeshadow palette, excitedly writing about the latest launches, or gushing over a new “must try” product. Before joining Cosmopolitan, she was the editor at The Everygirl, where she wrote and edited beauty content for four years. Follow her on Instagram to see her makeup selfies and new hairstyles every few months.