I have yet to find an actual deep conditioner that I love, &I've tried a lot. So I would say buy a not too expensive deep conditioner that promises moisture and prevents breakage, &add olive ol, jojoba oil, etc on top. &if you need protein, put an egg, acavodo, honey, mayonasia, or apple cider vinegar on your hair (keeping in mind too much protein can be a bad thing)
I have never purchased a deep conditioner. When I want to go the deep conditioning route, I usually make something at home. As Casey mentioned, there are tons of DC recipes that use ingredients that you probably have at home like bananas, coconut, avocado, honey, etc. Just do a quick search on the Naturally Curly site for some examples. Each recipe should let you know if it is for deep conditioning or protein (side note: I have never heard of ACV being used as a protein treatment--it is usually used to cleanse the hair and/or close the cuticle).
If you don't want to whip up your own, totally understandable. There are a number of women on the site who seem to love Creme of Nature's Argan Oil Intensive Conditioning Treatment. I've seen it at my local beauty supply for a buck fifty to two dollars.
Also, another great way to deep condition your own hair is apply a regular conditioner to your hair, put on a plastic cap and sit under a heat cap for about 45 minutes. When you rinse your hair use cool water to lock in the moisture. I love Carol's Daughter Monoi conditioner.
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