There is a little bit of truth to that because relaxers and heat tools both deplete hair of some of it’s structural components. This makes it difficult for our hair to stay moisturized; and dry hair is more prone to breakage and split ends. In most cases of excessive heat use with relaxers, the hair breaks away as quickly as it grows in. That’s why it seems like the hair doesn’t grow.
The key word is excessive heat use. Each person’s ability to grow longer relaxed hair while using heat differs. A safe bet would be to not use heat more than once a week (or every two weeks) and see how that works for you. For my fine and relaxed hair, I can use direct heat (flat irons, curling irons, blow dryers) for maybe 2-4 wash days in between my relaxers (that’s usually a 12 week span). Indirect heat (hooded dryers) I might use up to 2-3 times a month.
It is true that if I never used heat, my hair would get to longer lengths faster. But I’d rather use heat and take a little longer to get to my goals (Although I have been thinking about going heat free until my next relaxer, but… that’s just a thought at this point). Overall the goal is to do what we can to make sure our hair isn’t breaking off at the ends faster than the hair is growing from our scalp.
In addition to minimizing my heat usage, I maintain a hair regimen that incorporates strengthening and moisturizing hair products to keep my hair strong and elastic. I hope that this clears things up for you.
Happy Hair Growing,