I have never liked using hair oils despite being aware of it's benefits. My mum actively encouraged the use of olive oil but I couldn't stand the smell nor the way it left me feeling like a huge greaseball. In my ignorance I assumed that all hair oils (well the limited few I knew) were the same so avoided them. It was only when I started reading blogs that I learned coconut oil could be used as a hair treatment.
This is what I currently use (99p from Asda). It comes in solid form and has to be warmed up (I usually use a hairdryer) before it turns into an oil. I apply this to my hair every Sunday as a deep conditioning treatment, leaving it in all day before washing it out. I love that it has no discernible smell nor is it as viscous as olive oil - in fact it's quite light. I straighten my hair a lot and I feel that using coconut oil has helped to repair and prevent any further damage. My ends are quite dry but the coconut oil leaves it moisturised and looking shinier/healthier. With regular use it has made a noticeable difference to the condition of my hair.
I was reading up on the scienfics and came across this study in The Journal of Cosmetic Science. A few excerpts:
"Coconut oil was found to reduce the protein loss remarkably for both undamaged and damaged hair when used as a pre-wash and post-wash grooming product".
"Coconut oil, being a triglyceride of lauric acid (principal fatty acid), has a high affinity for hair proteins and, because of its low molecular weight and straight linear chain, is able to penetrate inside the hair shaft".
Rhamnousia and Amina have both done posts on hair oils which are worth a read.
Health Benefits of Coconut Oil
Coconut Oil for Hair
The Benefits of Coconut Oil in Black Hair Care