It depends on your priorities really. I've had a decent amount of regrowth on finasteride and I'm very pleased with the results. Ive been taking finasteride for some months now and the only sides i had were mild brain fog and increased fatigue. These sides wore off within a few months.
Severity and incidence of finasteride sides are completely overstated and in the vast majority of people who experience sides, they stop on discontinuing meds.
Nothing is guaranteed to work but finasteride retains hair on 90%+ of people and a fair amount get regrowth. The alternatives to finasteride (natural, diet etc) aren't even worth mentioning. They won't do anythjng to slow hairloss
If you're concerned that your hair is getting thinner and you're serious about stopping hairloss you'd be daft not to look into it.
At the very least I'd jump on Nizoral for the time being. Keep a close eye on your hair and keep informed