Dear Megan,

Can I use castor oil to thicken my hair?

– Shreya A. 

The short answer? Yes. If you want to know how to use castor oil to thicken your hair, keep reading.

Castor Oil for Thicker Hair – Does it Work?

Yes! I’ve used castor oil on both my lashes and brows–which are hair follicles, by the way–with pretty good success. In fact, castor oil the main ingredient in WINK. When I used castor oil alone, I didn’t see the same results as when I used a combination of essential fatty acids (Castor oil is high in Omega-6 via ricinoleic acid, but not any other EFAs). I actually did an A/B trial at MIT with half the participants using solely castor oil on their eyelashes every night, and the other half of the participants using a mix of Omega 3, 6 and 9 fatty acids together (which later became the formulation for WINK!).

If you want to know how and why castor oil works for hair growth, read a recent blog I published on it here.

As for the castor oil and the hair on your head, it does work, but man is castor oil thick and the consistency is oily because, well.. it’s literally just oil. So here’s how I would suggest using it:

Tip #1 for Hair Growth – Use Castor Oil as a Nightly Hair Mask

I’d mix it with a thinner carrier oil first, like Jojoba or Argan oil. Massage it into the scalp vigorously, wrap your hair in a towel, and let it stay in as an overnight treatment. Wash in the morning and rinse in cold water. It may take 2–3 washings. Here’s my recent experience with a jojoba oil-only overnight treatment. Your hair will be fabulously lush, but you will need to repeat this process every day for at least 4–6 weeks. That’s going to take awhile and the cost will add up quickly.

Tip #2 for Hair Growth – Mix Castor Oil into Your Hair Products

Alternatively, you can add some to your shampoo or conditioner. This will be much less effective, because you’ll be washing out the shampoo/conditioner within a few minutes, and the point is to let the castor oil absorb into the skin (scalp), and penetrate the hair follicles.

Tip #3 for Hair Growth – Use Castor Oil as a Mini Treatment Before Shampooing

A good middle ground is to apply a small amount into the scalp and massage it in, sit 15–20 minutes then shampoo and condition. Do this every day or every time you shower. This solution is the best mix of effective and efficient.

Final Takeaways

Castor oil definitely will help your hair thicken or regrow. The biggest challenges that you’ll face are 1. finding the time to fit it into your schedule and 2. sticking with it! The hair growth cycle for hairs on your head is much slower than thehair growth cycle for eyelashes and eyebrows, with the “resting” phase lasting up to 6 years. There is evidence that essential fatty acids can help stimulate dormant hair follicles to grow again, so hopefully you won’t be waiting 6 years for your hair to thicken. Just keep at it and use one of the tips above to work castor oil into your weekly (or daily) hair routine.

Good luck! May the thick hair gods be with you ?


*This blog is part of the Beauty Q&A series, where our founder Megan answers your toughest beauty questions every Tuesday and Thursday on the blog.  If you’d like your beauty question answered on the blog, email Megan at [email protected]

Dr. Vanessa Rodriguez is a board-certified general practitioner with more than 15 years of patient care experience. She takes an integrative approach to patient care that considers the whole person – mind, body, and spirit – and is deeply committed to assisting her patients in achieving and sustaining optimal health. Dr. Vanessa is also a skilled writer and medical reviewer, specializing in preventive care and health promotion. Her articles are written in an approachable manner that is simple to comprehend and implement in one’s own life. Dr. Vanessa’s mission is to equip her patients and readers with the knowledge and resources necessary to live their greatest lives.

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