Beauty Q&A


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


  • How would I do this if I don’t “wash” my hair? Twice a week or so I just use baking soda. I haven’t used shampoo in months.

    • Hi Stefanie,
      It would be difficult to fit this into a daily routine, but you could use a castor oil treatment once a week, similar to what I did in the “Oil Cleansing” blog, where I used Jojoba oil to cleanse my hair (which really turned into an oil treatment). You’d just have to plan to wash your hair with baking soda the next morning, after you leave it in as a night treatment. There will definitely be some trial and error. Let me know how it goes!!

  • Thanks for sharing such informative post!!

    Castor oil has some essential fatty acids and nutrients that help in your hair growth. You can even add few drops of rosemary essential oil along with the olive / almond /coconut oil. I personally prefer to use virgin oils as they retain the nutrients.

    Along with the virgin oils , one can also opt for hair thickening products like a professional shampoo.

    Keep on sharing more

  • I specifically use coconut oil to thicken my hair. I massage it gently on my scalp in circular motion. Doing so stimulates the follicles and encourages growth. I do this along with hair thickening products that my friends recommended. I’ll be following your post, it really is informative. Keep it up!


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