According to numerous TikTok videos on My FYP, the so-called benefits of castor oil for hair growth are numerous. The oil is renowned for making hair longer and thicker, especially in Jamaican beauty treatments, but also as an ingredient in homemade hair mask recipes and DIY tutorials. “Castor oil is an affordable option if you want to add shine, tame flyaways, and improve the condition of your hair,” says hairstylist and certified trichologist Courtney Foster. But why? Does hair really grow faster?
Before you start slathering your scalp with castor oil to stimulate hair growth, here’s what the pros have to say: Unfortunately, castor oil alone won’t promote hair growth (and, by the way, no other topical product can, except minoxidil, the active ingredient in Rogaine!). But it can help lock in moisture in your scalp and hair ends, helping to create a healthy environment for optimal hair growth. I spoke with a dermatologist and trichologist about everything castor oil for hair growth, including what it is, how it works, and how to properly use it at home to grow longer hair. Keep reading to learn all the 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 extracted. Jamaican black castor oil is one of the most popular varieties. It has a thicker consistency and a warm, toasted aroma because it is boiled with ash.
“Castor oil is rich in anti-inflammatory fatty acids, which improve circulation and can speed up the hair growth cycle,” says dermatologist Jessie Cheung, MD. The fatty acids give castor oil a thick consistency, 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 your skin: What clogs my pores may not clog yours).
“It’s also rich in antioxidants and has antibacterial and antifungal properties,” adds Dr. Cheung, making it an ideal oil for dry scalps and even dry hair. Scientifically speaking, “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 inflammation.” But do these hair-friendly proteins actually help hair grow? Read on.
Unfortunately, castor oil alone does not promote hair growth, says trichologist Shab Kaspara. Hill notes that while castor oil fans claim it can “stimulate” hair follicles and “promote hair growth,” there are no studies or scientific proof that castor oil helps hair grow. In fact, no topical treatment alone can speed up hair growth or prevent hair loss—only hormones, genetics, health, and age can do that, explains Hill. That’s why “hair growth requires a holistic approach” that includes healthy hair and scalp care habits.
While castor oil doesn’t promote hair growth, it can still retain moisture and soothe irritation, making your scalp healthier, 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 achieve success. Which brings me to…
All hair types can (and should!) use castor oil to add moisture and softness. However, how and how often to use castor oil depends on your hair type. Why? Caspara says that because castor oil is so thick, if you have fine, thin, or low-porosity hair, it can clog your follicles and make your roots greasy.
Below, we’ll go into more detail on how to use castor oil depending 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 product buildup that results from regular castor oil use.
How often you apply castor oil to your hair will depend on your hair type. But in general, “there is no standard frequency for using castor oil,” says Bleicher, “but I recommend doing it once or twice a week for at least three months, since that’s how long it typically takes for new hair to grow.”
There is no “best” oil for hair growth, as oil alone cannot stimulate hair growth. Remember: hair growth is a result of your DNA (primarily age, genetics, and hormones), which is why it is so 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 great for locking in moisture in the scalp and potentially reducing 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 are powerful sealants that help lock in moisture and prevent moisture loss.
It’s worth noting that rosemary oil has also been used to treat hair growth and hair loss, with promising results (though more human studies are certainly needed to prove anything). Dr. Cheung notes that a 2015 study comparing rosemary oil extract to minoxidil in men with genetically determined androgenetic hair loss found no significant difference between the effects at three months and six months. Patients also note that rosemary oil causes less irritation and itching, thanks to its 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 hair should apply castor oil to the midsection and ends of your hair and leave it on for 30 minutes before shampooing. On the other hand, people with coarse, thick, and very dry hair can use castor oil as an overnight treatment or as a leave-in conditioner, applying it to the ends of your hair. Hill’s tip: After massaging and applying castor oil, wrap your hair in a silk scarf for deeper penetration (and incredible shine).
Dr. Chang notes that the only potential downside to using castor oil for hair growth is that it’s so heavy that it can be difficult to rinse off your scalp, and it can also build up, causing breakouts and an oily scalp. “Castor oil has anti-inflammatory and antibacterial properties, so it can be beneficial for all skin types,” she says. “But be careful if you have sensitive or very oily skin, as there have been reports that castor oil can cause contact dermatitis and that washing your scalp can cause breakouts.”
The biggest risk with castor oil for hair is the potential for breakouts and buildup on your scalp, since castor oil is very thick and occlusive. To reduce the risk of breakouts, dermatologist Lily Talakoub, MD, advises avoiding castor oil near your hairline and being especially careful when applying it before bed, since it can transfer from your pillowcase to your face, which can lead to breakouts.
Hill explains that if your hair is already dehydrated, castor oil can make it feel 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 daily with a conditioner that contains other humectants like shea butter, glycerin, and panthenol before applying castor oil. You can also combine castor oil with a deep conditioner (either a castor oil-based formula or adding a few drops to your favorite formula) to keep your hair from looking dry.
And like all ingredients and products, castor oil can cause irritation and allergic reactions, so before applying castor oil to your scalp, do a patch test on your neck first, especially if you have sensitive skin. Castor oil is not a common irritant, but hey, better 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 depends entirely on your hair type and concerns. As a reminder, Jamaican black castor oil is thicker, so it’s best for those with thick or coarse hair, while regular cold-pressed castor oil is great for fine hair. Here are a few options to try:
Hairstylist Natasha Burrell likes to use castor oil to massage your scalp and condition your hair from top to bottom. After massaging your scalp and applying castor oil for 5 to 10 minutes, Burrell recommends sitting under a steamer 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 leave it in until your next wash day if you have coarse, damaged, or dry hair.
If you have fine to medium-thick hair that tends to get oily, apply castor oil to your mid-lengths and ends and leave it in for 10 minutes before shampooing. But if you have medium to thick hair, you can massage castor oil into your roots, then massage it into your ends and leave it in for an hour (or overnight) before rinsing. Hill also recommends sitting under a blow dryer with a fan to help the oil penetrate your hair.
For a more personalized treatment, you can mix castor oil with other carrier oils, like jojoba or coconut oil, to dilute the castor oil and make it thinner, making it easier to use even on fine hair, Burrell suggests. On the other hand, if you want a richer formula, you can mix castor oil with olive oil for a deep conditioning treatment (however, never use this method on fine or low-porosity hair).
If you have medium-thick hair that is prone to frizz, you can add a few drops of castor oil to your conditioner once or twice a week to add extra moisture to your hair, leaving it smooth and 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 rinse with shampoo and conditioner. Note: You may need to wash your hair twice to completely remove the castor oil if you don’t want any traces of it to remain.
For gentle scalp care, mix castor oil with olive oil, grapeseed oil, coconut oil, and vitamin E oil in an applicator bottle and apply every night before bed or whenever your scalp feels itchy or dry. Check out this guide to learn how.
Before bed, dip a clean eyelash brush or cotton ball into a small amount of castor oil (you only need a little) and gently wipe it along your lash line, being careful not to get any oil in 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 faster, it can do the opposite. According to celebrity eyelash extension expert Dionne Phillips, castor oil is great for removing eyelash extensions at home, which she previously told Cosmo magazine. Simply use the same cotton-tip technique described above to loosen the glue and remove the extensions while moisturizing your natural lashes.
Castor oil is safe, as long as you don’t apply it directly to your lashes and brows. But remember: Castor oil isn’t guaranteed to make your lashes grow faster, though it can serve as a great lash care 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 thin and easily clogged, so “using castor oil around your eyes can aggravate milia, blackheads, and pimples,” says Dr. Talakoub. Incidentally, 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 with caution.
Unfortunately, castor oil won’t automatically make your hair grow (only genetics and overall health can do that). But it is still very moisturizing, meaning it keeps your scalp and hair hydrated, which is a great environment for stimulating hair growth. Remember to be careful about everyday activities that can contribute to hair loss and breakage, such as wearing your hair too tightly (like braids and tight ponytails), brushing your hair too hard, and using excessively hot styling products. Because while castor oil is moisturizing, its benefits for hair growth are limited.
Beth Gillette is Cosmopolitan’s beauty editor with over five years of experience researching, writing, and editing articles on skin care, from hair growth devices to hair Botox. She’s an expert on all things hair, but she’s an expert on using castor oil for hair growth, having tested dozens of hair growth products to finally grow her own forever locks. She regularly tests and reviews the effectiveness of hair care products, working with the industry’s leading trichologists and hairstylists to evaluate new formulas and brands.
Brooke Shunatona is a staff writer for Cosmopolitan magazine with over 10 years of experience writing about beauty, style, and lifestyle, including microfiber towels and the best hair straighteners. She knew a lot about castor oil for hair growth thanks to information, product reviews, and ratings provided by experts.
Beth Gillette is the beauty editor at Cosmopolitan magazine, covering skincare, makeup, hair, nails, and more across both digital and print. You can usually find her swiping on bright eyeshadow, furiously writing about her latest feature, or hesitantly recommending a new “must try” product. Before joining Cosmopolitan, she spent four years as an editor at The Everygirl, where she wrote and edited beauty content. Follow her on Instagram to see her makeup selfies and new hairstyles every few months.