There’s actually a really good reason for that. The body doesn’t have a good way to get rid of excess iron except by bleeding, so it’s fairly easy for someone without a period to get iron poisoning from vitamins with iron in them. Women’s vitamins assume the person taking them loses a significant quantity of blood every month. Not only should men not take them, women whose birth control eliminates their period completely shouldn’t take them either.
This seems like a shitty proposition…