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Castor Oil for Hair Growth

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by James Roland

Published 02/27/2021

Updated 10/28/2024

The search for an effective hair growth treatment can have you considering some unexpected options. You’re no doubt familiar with prescription hair loss treatments such as finasteride and minoxidil, as well as countless over-the-counter options that may or may not provide any benefits.

Some of those familiar products include hair treatments containing saw palmetto or onion juice. They’re right alongside aloe vera hair loss remedies, and most of them are a dime a dozen.

But you may not know as much about coconut oil, carrier oil, and other natural oils used to stimulate hair growth and slow hair loss. 

Another product you may not know much about, but that is used by plenty of guys is castor oil for hair growth. Castor oil is a rising star in natural remedies, particularly natural health and beauty, but it is nothing new. Unfortunately, it may not be all it’s cracked up to be. 

In this guide, we’ll look at the science behind castor oil for hair growth. We’ll explore the research supporting this natural remedy and talk about the potential benefits of castor oil for your hair. We’ll also cover how to use castor oil for hair growth. 

Castor oil is derived from the castor bean (Ricinus communis). It is typically produced by pressing the bean and purifying the resulting oil to remove toxic components like ricin. 

This multipurpose oil has been used for thousands of years. In ancient Egypt, castor oil was used as lamp fuel. It was even an ingredient in car and machine oils for a long time.

Medicinally, castor oil is commonly used as a stimulant laxative, and in homeopathy, it has been used to stimulate labor and lactation

Today, castor oil is often used as an additive in food, pharmaceutical, and cosmetic products. 

Regrow Hair

All about hair, here

Oils play a significant role in protecting hair from damage. Some research suggests regularly applying hair oils like castor oil may help prevent breakage, which can potentially help repair damaged hair and stimulate healthy hair to grow longer.

Though castor oil is best known for its use as a natural laxative, it has recently gained popularity as a natural remedy for hair growth. Because it’s rich in ricinoleic acid, castor oil is purported to reduce scalp conditions like dandruff, moisturize the hair and scalp, and increase the strength and flexibility of hair follicles. 

But any claims of hair growth benefits are anecdotal at best. Unfortunately, there isn’t any recent scientific evidence to show that castor oil promotes hair growth. That being said, some of its properties suggest that castor oil for hair loss may be worth a try.

For example, castor oil is 90 percent ricinoleic acid, a monounsaturated fatty acid. Fats play an important role in keeping hair follicles moisturized, healthy, and strong. 

Some research suggests that ricinoleic acid may help moisturize the scalp and nourish hair follicles. For example, a study of various herbal ingredients in hair loss treatments found that castor oil was among those with the potential to be a safe and effective treatment for slowing hair loss.

Ricinoleic acid also stimulates prostaglandin E2 receptors, which play a role in triggering blood vessel dilation. When applied to the scalp, castor oil could, therefore, help increase blood vessel dilation by boosting the flow of oxygen- and nutrient-rich blood to the hair follicles. Again, there is no current scientific evidence demonstrating this direct effect, but anecdotal evidence suggests castor oil may improve the growth or appearance of hair. 

On top of consisting of monounsaturated fatty acids, castor oil offers antioxidant, anti-inflammatory, and antimicrobial properties

Castor oil contains the fat-soluble antioxidant vitamin E. This vitamin helps protect against oxidative stress, which has been implicated in certain forms of hair loss, including alopecia areata. Some research suggests supplementary vitamin E may improve hair growth in patients experiencing hair loss by reducing oxidative stress in the scalp.

Vitamin E may also help lock in moisture on the skin’s surface on the scalp, which promotes hair health. Plus, oils that contain vitamin E — like castor oil — may also improve shine by adding a protective layer of fat to the outside of the hair cuticle.

Of course, we should note that in our research for this article, we couldn’t find any specific studies on castor oil and its effects on things like hair loss and hair shine — so, for now, take this as a mere “perhaps.”

If you want to try a castor oil treatment for your hair, we recommend using cold-pressed castor oil. You can find it online or at your local health food store. 

Because castor oil isn’t a science-backed treatment for hair loss, there are no “official” guidelines for its use. A little trial and error may be necessary to learn how to use castor oil for hair growth and thickness.

As with many hair products, consider starting with a small amount of castor oil for your first application. We recommend doing a patch test by applying a bit of castor oil behind the ear once daily for a week before progressing with intensive treatment. 

If your behind-the-ear tests seem promising, or you want to give the rest of your scalp a dose of castor oil, then give it a try.

Here’s our best advice:

  • Start by filling a small bowl with castor oil. Dip your fingers into the oil, then gently massage it into your scalp with your fingertips. 

  • Work in sections, coating each section thoroughly with oil. 

  • When you’re finished, sit under a hair steamer to boost penetration. If you don’t have access to a hair steamer, simply let the oil soak overnight before washing. 

  • Before going to bed, put on a shower cap to keep the oil in place while you sleep — and protect your pillow.

  • In the morning, gently comb your hair with a wide-toothed comb to work out any tangles before washing with shampoo and conditioner. 

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Before/after images shared by customers who have purchased varying products, including prescription based products. Prescription products require an online consultation with a healthcare provider who will determine if a prescription is appropriate. These customers’ results have not been independently verified. Individual results will vary. Customers were given free product.

You can also use castor oil as part of your regular hair care routine, whether you’re dealing with thinning hair, split ends, or other challenges. Your hair type may determine how you use castor oil.

For example, if you have fine, straight hair prone to tangling, you can use castor oil as a protective treatment before you shampoo. 

Apply the castor oil sparingly to hydrate dry ends to prevent tangles. Simply dip your fingers in castor oil and work it gently into the ends of your hair by hand. Shampoo, rinse, and style as desired. 

Castor oil is a good frizz-fighter for wavy to curly hair, especially during the summer. Try adding a few drops of castor oil to your conditioner. 

If you have tight curls or coiled hair, you may also want to use a little as a pre-shampoo treatment for added protection. 

When using castor oil as part of your routine, it is wise to use clarifying shampoo once a month to help rinse out excess oil so it doesn’t weigh down your hair. 

Whatever treatment you choose, remember that hair growth doesn’t happen overnight — you’ll need to give the treatment time to work. For example, with scientifically backed hair loss treatments like minoxidil, you’ll need to use the product consistently for at least a few months to see any visible improvements. 

Hair loss treatments, delivered

Whether you’re struggling with male pattern baldness, stress-induced telogen effluvium, or diffuse thinning related to age, you are far from alone in your battle against hair loss. 

Hair loss affects more than two-thirds of all men by the time they reach thirty-five, and by the age of 50, roughly 85 percent of men experience hair thinning. 

So, it’s no wonder you can find a seemingly endless list of hair loss treatments. If you’ve tried some with little or no success, castor oil may be worth a shot.

Castor oil is generally considered safe, but you should still be cautious when using it. It has been known to cause adverse reactions, such as diarrhea and allergic reactions in some people, so be sure to try that test patch before using it. 

It’s important to remember that even if castor oil has the potential to improve the condition of your hair and scalp, it isn’t a medically proven treatment for hair loss. If you’re looking for a solution backed by science — and by the Food and Drug Administration — we recommend looking into finasteride or minoxidil. A dermatologist or other medical professional may be able to advise you about your concerns and write a prescription if necessary.

To learn more about FDA-approved remedies for hair loss, start with a free online consultation or explore our hair loss treatments yourself.

9 Sources

  1. Drugs and lactation database. (May 1, 2019). Castor. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK501875/
  2. Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Castor. [Updated 2021 Feb 15]. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK501875/
  3. Mysore, V., et al. (May-June 2022). Hair Oils: Indigenous Knowledge Revisited. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9231528/
  4. Fong, F., et al. (Dec. 4, 2015). In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss. https://pubmed.ncbi.nlm.nih.gov/26456343/
  5. Iqbal, J., et al. (2012). Antioxidant, Antimicrobial, and Free Radical Scavenging Potential of Aerial Parts of Periploca aphylla and Ricinus communis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3418662/
  6. Guo, J., Sun, N., & Wang, F. (1999). Effects of castor oil - diet on the synthesis of prostaglandin E2 in pregnant rats. Zhongua fu chan ke za zhi, 34(3): 147-9. Retrieved from https://pubmed.ncbi.nlm.nih.gov/11263183/
  7. Naik, S.N., et al. (2018). Chapter 21 - potential and perspective of castor biorefinery. Waste Biorefinery, P 623-56. Retrieved from https://www.sciencedirect.com/science/article/pii/B
  8. Taghipour, K., Tatnall, F., & Orton, D. (2008). Allergic axillary dermatitis due to hydrogenated castor oil in a deodorant. Contact dermatitis, 58(3): 168-9. Retrieved from https://pubmed.ncbi.nlm.nih.gov/18279156/
  9. Introduction. (n.d.). Retrieved from https://www.americanhairloss.org/men_hair_loss/introduction.html
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Knox Beasley, MD

Dr. Knox Beasley is a board certified dermatologist specializing in hair loss. He completed his undergraduate studies at the United States Military Academy at West Point, NY, and subsequently attended medical school at Tulane University School of Medicine in New Orleans, LA. 

Dr. Beasley first began doing telemedicine during his dermatology residency in 2013 with the military, helping to diagnose dermatologic conditions in soldiers all over the world. 

Dr. Beasley is board certified by the American Board of Dermatology, and is a Fellow of the American Academy of Dermatology.

Originally from Nashville, TN, Dr. Beasley currently lives in North Carolina and enjoys spending time outdoors (with sunscreen of course) with his wife and two children in his spare time. 

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  • Dermatology Residency. San Antonio Uniformed Services Health Education Consortium

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