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Science Confirms Castor Oil Does Not Thicken Hair Strands

• Dec 7, 2015

It’s one of the first recommended remedies when naturals complain of thin strands or weak edges; “Girl just rub it with some castor oil!” And many women swear by the thickening and strengthening properties of castor oil, but what if it’s not scientifically proven! A detailed article from explains why castor oil does not actually thicken strands of hair

…it is biologically impossible for the physical hair strand to become thicker after it has emerged from the scalp. Therefore, it should make sense that products applied directly to the hair that promise to increase the thickness can only deliver the illusion of actual hair thickness. In order to physically grow thicker strands of hair, you would have to address the problem at the root (pun intended)…”

But what about the many naturals who swear by incredible results from castor oil?

Improved hair density due to a castor oil treatment could be attributed to the lubricating of the scalp with an oil known to have anti-inflammatory and antibacterial properties, which can help clear up bacterial infested follicles. This can most likely be achieved with other oils such as rosemary or tea tree oil. In addition, it is often encouraged to lightly massage the oil into the scalp. A scalp massage alone could possibly stimulate blood circulation, which may help the flow of nutrients in the papilla. In this case, results would not be limited to the use of castor oil, but any product associated with a scalp massage or scrub. In my opinion, this all comes down to a personal preference.”

Blogger and biologist Jc of the Natural Haven also credits castor oil’s stickiness for its perceived thickening qualities.

…castor oil perhaps can stick to hair more firmly than most oils and therefore create an illusion of thickness. Anyone who has used it will note how thick and viscous it is. It is almost like a soft glue and tends to stay put and not move when applied. It does not transfer easily either, which means that it can attract small particles of dust and lint which may also add to the illusion of thickness.”

Hmmmm.… Well we’re certainly not going to ditch our castor oil! It is still an incredible oil with great sealing and strengthening abilities.

Ladies, what are your thoughts?

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10 Comments on "Science Confirms Castor Oil Does Not Thicken Hair Strands"

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I figured this out back in 2009 that it doesn’t thicken strands, it just coats it. Similarly to the texture and stickiness of mineral oil also. It attracts lint and other particles to the ends to look thicker. The more you rub in, the more particles twist and attach to your hair causing an illusion. Henna also sticks the the hair too and stays bc it’s like a clay. Once you stop using henna, you no longer have that reddish clay after color and the thickness also fades too. So I just stuck with using sesame, peanut, or any oil… Read more »

Well I am happy you are sharing this info because *cough cough* some major hair brands that cater to us — MMMMM WHY YOU LYING?! Castor oil is great for hair though, no doubt.


I have been into natural hair sites for 4+ years and have never heard that black Jamaican castor oil made strands thicker; I noted on my research that it help regrow and retain your edges, aaarrrggghhh, what’s up with that headline!


Yeah, I’ve never heard that either. I’ve heard that it stimulates hair growth and I believe that to be true. I’ve been using it as a face mask to seal in moisture on my skin and my sparse eyebrow hairs have gotten longer. It’s strange, but now they look more full, so I’ll take’em


Science is a discourse like anything else. One day scientists know some, the next day they learn something else. Scientists don’t have all the answers.


Well, what I DO know for sure is that JBCO was the only thing that helped restore my edges so I’m forever a fan!


Yes, but people don’t use castor oil to thicken their individual hair strands, but to restore thin edges (increase the *number* of individual hair strands). And even this post admits that by killing bacterial growth on your scalp, it allows dormant follicles to produce hair and accomplish just what these ladies are looking for. 🙂


Oh well, it solved my bald edges issue so i’m still using it. Before i started using JBCO my hair line was receding rapidly. I genuinely believe this stuff stimulates hair growth.

Nicole Hunter

I don’t care what the scientist is talking about. Just like doctors don’t know everything and even their tests can be wrong, so can the scientist!


It works!

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