The statements below are the ones that I have found so far in the scientific literature that pertain specifically to hair.  There are more studies that show benefit to internal health, but those studies are irrelevant to hair care. That being said, if you know of hair studies to add to this list, please cite them in the comments section and I will add them to the list below!

Reduced protein loss from inside the hair strand.

Your hair gets its strength from the proteins within it, so protecting the integrity of those proteins is very important. Coconut protects those proteins by absorbing into the hair fiber [1, 4, 5], and reducing the protein loss for both undamaged and damaged hair [1]. Apply a thin layer of coconut oil on your hair before showering (focus on your tips to mid-length), as well as a thin coat once your hair has dried.

Better protection from water swelling.

Hair that gets pre-treated with coconut oil before water immersion shows less water-induced swelling. This means that pre-oiling your ends before showering can protect your hair from water damage. On the flip side, some of the water that does come in stays in longer due to the coconut oil.  Taken together, this means that coconut oil helps to balance out the water variability in your hair [2].

Protection from combing damage.

Brushing and combing physically damages the cuticle, aka, the protective outer layer of the hair strand that keeps the hair strand water-tight and healthy. Coconut oil reduces that damage by forming a more “slippery” surface so that the friction between the comb and the hair—as well as between the individual hair strands—is decreased [4]. It also appears to penetrate into the endocuticle layers and prevent endocuticle swelling from water (another way that wet brushing damages the cuticle) [4]. This is the biggest way in which coconut oil is like a conditioner; it helps keep hair manageable and comb-able.

Which Coconut Oil Product to Get

Whichever one you want.

I personally buy in bulk because coconut oil lasts for years in the fridge, and its soo much more affordable in the long term. So as long as you have some extra room back there, buy a tub of coconut oil and take small portions out at a time and keep them in a small container.

This is my personal opinion, but I’ve found the bulk gallon of Nutiva Organic from Amazon to be the best value for the money.  It’s organic, yet at 14 cents per ounce, it’s almost three times less than the standard-sized jar you find at your local health food store or online.

References:

1. Rele AS, Mohile RB. Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. J Cosmet Sci. 2003 Mar-Apr; 54(2) 175-192. PMID: 12715094.
2. Keis K, Huemmer CL, Kamath YK. Effect of oil films on moisture vapor absorption on human hair. J Cosmet Sci. 2007 Mar-Apr; 58(2) 135-145. PMID: 17520153.
3. K. KEIS, D. PERSAUD, Y. K. KAMATH, A. S. RELE. Investigation of penetration abilities of various oils into human hair fibers. J. Cosmet. Sci. 2005 Sep-Oct; 56, 283-295
4. Rele, A. S., & Mohile, R. B. (1999). Effect of coconut oil on prevention of hair damage. Part I. Journal of cosmetic science, 50(6), 327-340.
5. Ruetsch, S. B., Kamath, Y. K., & Rele, A. S. (2001). Secondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair. J. Cosmet. Sci, 52, 169-184.