A deep conditioning treatment (DT for short), also called "hair mask", is usually a creamy blend of different conditioning and nourishing ingredients usually (but not necessarily) left on the hair anywhere from 5-30 minutes (sometimes a heat source is used) and then rinsed out. Its purpose is to help restore moisture and protein to the hair which are lost during styling.
Unfortunately, many so-called DTs contain a large amount of silicones which coat the hair forcing the cuticle (outer layer) shut giving it the appearance of health and they also often contain synthetic humectants and other ingredients that don't have a lasting benefit for the hair. So when you look for one please read the labels and look among the first ingredients protein such as silk or soy or amino acids (to "fill" any gaps in the cortex - inner layer - and cuticle), moisturizers such as panthenol, honey, sorbitol, aloe vera and vegetable glycerin and emollients such as shea butter or vegetable oils such as jojoba, coconut, avocado, etc. Some herbal extracts are good for the hair but those can be optional.
I am wondering though why in the world you are straightening your hair and then tying it into a ponytail... Is it because you can't get your hair straight enough? If so, why not wear your natural curls???
Anyone who is putting heat to their hair that often should use a DT every week AND use a rich CO after washing their hair and maybe a leave-in also or apply the protective serum ALL OVER the hair, not just the bangs...
2A/3A, medium length, layered, colored dark/medium ash blonde - "CGer" since April '02.
"Converting the 'curlskeptics' one curly head at a time..." HWHC