I know growth aids come with their pros and cons. You shouldn't apply them to the scalp due to possible scalp irritations and build-up, but that can also depend on the person. I don't think it causes problems for all people, just for some depending on the scalp
I have dry, itchy scalp, not flaky or dandruff though and I have tried MN, castor oil, megatek and sulfur mix. The MN caused too much itching and intense shedding after 7 weeks for about 2 weeks after I stopped using it. Castor oil causes intense shedding so I stopped. Sulfur was too drying and cause itching and dandruff (weird huh). The only thing that never caused itching was the megatek, caused growth and actually stopped a majority of my itching without build-up. I haven't used anything on my scalp in a while except my hot oils but because of so many reactions I barely bother anymore.
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