From prior research on substances that change hair texture, I read in the past (and couldn't find lots of sources now) that some Vitamin A derivatives or acne medicines can cause curly hair and that some anti cancer drugs can cause changes in hair texture (if not hair loss):
- Isotretinoin and curly hair
- Isotretinoin and azathioprine: a synergy that makes hair curl?
- ‘Chemo curls’ another kink in cancer recovery
I further learned that some
endogenous hormones created in human female body at pregnancy can cause hair to go
somewhat straight in woman with "curly hair" or
somewhat curly in woman with "straight hair"; I assume it is a common claim (which might be false or exaggerated) in newspapers and blogs:
- Nice anecdote by Momma PhD → https://mommacommaphd.wordpress.com/2012/01/23/pregnancy-made-me-lose-my-curls/
I personally never came across evidence that these
hair texture changing
endogenous hormones have ever been isolated and formulated by biochemists.
I didn't find any indication that any substance that makes "curly hair" straighter can be somehow administered to the body (putting state-dependent legal-issues aside for a moment).
Are there any substances that can make the hair grow more straight or smoother?