Sugar and opioids are also legal, legality doesn't solve everything, it's also up to the consumers and the regulator to work on better ways to consume those products.

You would need to regulate doses, make sure it's not coupled with other substances to reduce ill effects on consumers, which isn't easy. It's obviously better than letting cartels thrive, of course, but legalizing drugs isn't a silver bullet, it's also a lot of work.

Remember how prohibition went into action: women were tired of their drunk husbands.