Does Castor Oil Increase Hair Thickness and Rejuvenate Edges?

By Jc of The Natural Haven Bloom

So let us take a straw poll. How many of you have heard that castor oil can help improve the thickness of natural hair? I have seen this said many times, and since hair thickness is dictated by genetics, I have always wondered if there was any truth to the statement. I finally decided to research it.

First question – what is in castor oil?

Like many natural oils (coconut oil, shea butter, olive oil etc), castor oil is composed of several fatty acids. In reality, these acids are bound and therefore do not really behave like acids at all (note that you cannot pH an oil as it does not dissolve in water). The dominant fatty acid in castor oil is ricinoleic acid.

Can ricinoleic acid or any other of the fatty acids in castor oil increase hair thickness?

There are no scientific studies to prove that castor oil can increase hair thickness. Interestingly, in the field of male pattern baldness where hair thickness improvement is a major requirement, castor oil does not even feature as a research ingredient.

What about the pictures where naturals show an improvement in hairline/bald patches by rubbing castor oil?

In my opinion this is not evidence because massaging in itself even with plain water can stimulate regrowth of hair (i.e where hair has fallen out or been pulled out, massage can help a new strand to grow back). I would add though that the study that showed this was done in rats and not humans.

Additionally, I have not seen anyone measure the actual diameter of hair to show that castor oil use has thickened their hair. Some people refer to thickness as the overall density of hair and in my view again this is not proven by the pictures as often they are just referring to normal regrowth.

Could something else be at work?

My theory in discussion with my chief chemist (i.e the husband) is that 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.

Do you really need to change your hair thickness?

In my view, I think that life and biology is about diversity. Not everyone can have thick hair strands, not everyone can have high density hair but everyone can have great hair regardless of how thick the strand or how dense the hair.

Ladies, do you use castor oil? Has it help improved thickness?

The Natural Haven

The Natural Haven

Scientist on a hairy mission!


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79 thoughts on “Does Castor Oil Increase Hair Thickness and Rejuvenate Edges?

  1. Hi well for me personally I have suffered with a hairline problem after repetitive times placing my hair in a tight bun or pont tail. A year ago I started to massage the area and a year later i have seen a vast improvement.

  2. Well, I’ve used Jamaican Black Castor oil on my edges…there were two particular spots where my hair was not growing at all anymore for like 3 years, due to braids that were too tight. I used the JBCO and my hair started back growing….I stopped using it and the hair growth stopped (the hair that had grown did not fall out though).

  3. I have been using Castor oil for the past year (pic right afterBC on 9/10 and now) and I most definetly believe that its had an effect on my hair growth and thickness.. I Love It!


  4. Interesting i guess Castor oildoes something even if scince doesn’t want toresearch it or validate it. Science is what it is knwledged but when it comes to hair journeys i’m afraid it’s about an idnciduals experience.

    I love castor oil it is brilliant added to a deep condtioner and a great source of moisture.

  5. This is interesting, I was wondering about Caster oil, had it on my list of things to try. My sweetie left some Jamacian Blask Caster oil at my house on accident and he lives out of town so…. I’m gonna start using it in the oil combo I use to massage my scalp with and see if I notice any difference in my growth/thickness.

  6. I can understand where castor oil would cause a buildup of particles that would mimic thickness of the hair. I would not use it because of that. I like to use light and non greasy hair products for my hair, especially in the summer and also use a purifying shampoo and conditioner. Thank you for this information :)

  7. I am a black castor oil advocate. I primarly use it on the ends of my hair and to seal in moisture; it works wonders against single strand knots. Not sure about it making my hair thick because my hair is already thick. But I love that castor oil goes a long way, you don’t have to use a lot.

  8. She didn’t really answer the question whether it rejuvenates edges. Thickness is one thing, but if you have some traction alopecia and you want to recover your normal thickness back – would castor oil help?

    • I think she did address it she said this:

      “In my opinion this is not evidence because massaging in itself even with plain water can stimulate regrowth of hair (i.e where hair has fallen out or been pulled out, massage can help a new strand to grow back). I would add though that the study that showed this was done in rats and not humans.”

      I think she is saying that people are equating the benefits of castor oil with castor oil and massage in the case of regrowth. If you are using both castor oil and massage it is difficult to determine if the castor oil is playing a role or not and so far their hasn’t been a study that proves its benefits. I use castor oil as a sealant like any other sealant but I think the reviews about its benefits as a product that creates thickness and growth, on its own, are overrated.

  9. I don’t know if it rejuvenates your hair or not…BUT have I noticed a difference in using castor oil?

    YES!!! Water (for moisture) and Castor Oil to lock it in and I’ve seen my hair flourish. It’s amazing.

    I use the castor oil pictured above. I just purchased a new bottle of it. I hope to use JBCO one day.

  10. I wonder if there is a difference between using castor oil and jamaican black castor oil. I know that the process of creating jamaican black castor oil is vastly different than just regular castor oil because they slow cook or burn the seed. This might infuse some sulfur into the oil that could help with hair growth (MSM is the sulfur that i believe is in a lot of hair growth supplements that actually work but i could be wrong). I have never used regular castor oil but I swear by Jamaican black castor oil and incorporate it faithfully into my regiment to keep my edges thick while i have senegalese twists, keep my edges laying flat and looking fly, as well as to seal my ends. This oil prevents splits ends like crazy and its wonderful

  11. I tried castor oil one time on my fine hair and it felt like it was stuck to my hair, like a really tacky feel but I want the benefits so I will try again lol

  12. “There are no scientific studies to prove that castor oil can increase hair thickness. Interestingly, in the field of male pattern baldness where hair thickness improvement is a major requirement, castor oil does not even feature as a research ingredient.”

    this statement means nothing. i’m a lover of natural foods and believe that a whole foods approach to living makes eliminates many maladies. up until recently, the “scientific” community dismissed this form of thinking.

    absence of studies or certain things not being studied means little to me in light of said perspective on food and health.

    you’ve drawn conclusions based on scientific research that by your own admission, doesn’t really exist.

    in this case, the opinion expressed here is no more valid than the actual firsthand castor oil experiences that are being dismissed, imo.

    • co-sign! she’s saying there’s no studies to prove the benefits, so how can she conclude that it doesn’t do anything? contradiction much?

    • I agree with Merry. My boyfriend is a scientist, and he likes to proclaim the superiority of science. But I believe that history itself has proven that science is not the end all, be all. Remember when we all thought Pluto was a planet? That was “science” until, well, it wasn’t.

      I also agree with Merry’s point about the whole foods movement not being recognized by the medical establishment. Watching documentaries like Fat, Sick and Nearly Dead and The Gershon Miracle have helped me to realize that, just like anything else, science and medicine are inundated with biases and traditions that can negatively their results.

      Bottom line–if you are looking for a growth aid, I say give castor oil a try. I have never used it in this way, but I think the hundreds of personal experiences you can find online are just as important, if not more than, the lack of scientific trials on this topic. Maybe it will work for you like it has for so many others, maybe it won’t.

      Happy hair growing!

  13. I have use castor oil on my edges for approx. 2 1/2 years and I have noticed a vast improvement in the growth of my hair. My hair loss was due to improper use of relaxers, pulling my hair too tight and sulfate shampoos. I have eliminated the relaxers, braids and sulfate shampoos and I do believe the castor helped to regrow the hair that I lost. I also use it to seal my hair after applying moisture. It is worth a try and it far more affordable that some other alternatives out there. ;)

  14. jbco has helped my hair. i mix it with olvie, coconut and tea tree oil. i used the lavender jbco and my edges are very full now, now that they were thinning out but the jbco mix i use really helped with keeping my edges and ends moisturized.

  15. I believe castor oil works. I gave my SIL qhemets amla cream which has a lot of castor oil. Next thing I hear is that my brother has had to start going to the barber more frequently after he started using it and had to ditch it because of that. He’s a guy and doesn’t massage his hair or do any special treatments. (unless applying the product counts as massaging?) and the qhemet product was the only thing he changed.

    I’ve also used castor oil on its own (I discovered that avocado oil works too) to grow in my eye brows and I see growth in areas that I usually don’t get hair. Ive also used it to help my edges fill in..I know it’s empirical evidence but it’s consistent from my experience. As long as its not harming you, there’s no problem trying it out.

    Now I’m still trying to see if JBCO is better than normal castor oil. I hear yes and no but strawberricurl’s testimony about her mom growing her edges back in with JBCO haunts me!

  16. I have an eyebrow that won’t grow (all the way to the end/length of the other one) and the indian lady who threads them for me told me to use castor oil to make it grow. It did work for growing the hair but my hair is already thick so I don’t know if it did anything for the thickness.

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