Low porosity hair is very resistant to hydration. Heavy oils like olive and castor will sit on top of the hair and create build up in short periods of time. Lighter oils, that have the ability to penetrate the cuticle layer of the hair, should be used to maximize hydration.
Fractionated Coconut Oil - Coconut oil is a big no no for low porosity hair, but removing the fatty acids transforms it into a wonderfully light oil that low porosity hair loves. Not only does it penetrate the hair shaft, it helps to smooth the cuticle and reduce frizziness.
Moroccan Argan Oil - Argan oil is super softening, rich in vitamin E and ferulic acid. It is one of the best oils for low porosity hair.
Grapeseed Oil - One of the lightest oils on the market, grapeseed oil penetrates the hair shaft and has the ability to seal in moisture without being super heavy on the hair.
Sweet Almond Oil - Vitamin A, vitamin E, proteins, zinc, and potassium. On the acid front, sweet almond oil contains oleic acid, stearic acid, palmitic acid, and linoleic acid. Need I say more about this wonder oil??