Saw pictures of a ladies "hot combed" hair. She had it done professionally at a salon.
It was melted. No amount of conditioner, moisturizer, nothing made the natural hair snap back.
Also heard many scary stories of ones who have had the blow dry/wrap under heat/flat iron treatment (I forgot what that is called). So much heat at one sitting caused the hair to melt and evenutally break.
Your hair has a measure of moisture in the center of the hair shaft. When you apply heat to it, that moisture heats up and escapes. That is why many complain that their hair is dry after blowdrying or flat ironing. If too much heat is used and the moisture within the hair is gone, the next phase is over heating the actual shaft, melting it. Once something is melted...it cannot recover. You will either have to cut off the damaged ends or live with the limp, frayed ends.
Whatever we chose to do to our hair will always show up one way or another. So the choice is of course up to us individually on if we use heat or not.
It does seem like the sisters on here with long hair that looks healthy from root to ends...avoid heat. I use that as my guide on if I will accept the advise from someone on a hair subject. How does the ends of their hair look? Does the length of time they have been growing it prove they are following their own advice? (If you have been growing your hair for 5 years-never cut it and you only have 2 inches of hair and you hot comb your hair every day...I am not so sure I would follow your hair routine.
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I know my hair would not react well to heat, so I choose to avoid heat altogether. I know some have seen no adverse affects of using heat appliancs on their natural hair. Some have had damage after one time. I guess it simply boils down to whether you are willing to take the risk or not.