What does this mean? Weak hairshaft?
ETA: a single hair is split in the middle, but not on the end
Technically, this problem is the same as split ends, just that the weakness goes up further up the hair shaft. It could be due to external cause (products used, hard water, way of handling the hair, etc.) or internal (protein and vitamin deficiency, illness, medication taken, etc.). Protein-rich DTs are needed and hair must be kept well moisturized and softened with emollients (preferably vegetable oils or butters). Weeding out the damaged hairs you find is good because that way they won't tangle with the others maybe causing them to break too.
Can you share which products you've been using and how long you've been doing CG? It would also be helpful if you described your hair length and at what distance from the roots you have found the breaks. This way we can calculate how old the hair is at the point of break and if it may have anything to do or not with CG. Also, I want you to think if there were any significant changes in your life several months to a year ago (such as pregnancy or a lot of stress) as this could've caused the hair to grow in weaker for a while.
Thank God they're random, right? They're a good reminder to apply a little more TLC than usual. Btw, eight months in between trims is waaay too long even if you're trying to grow your hair out, try to get at least 3 a year, if you warn the stylist to just "clean up your ends" because you're letting your hair grow she/he will understand.
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