alt Hacker News> With 90%+ efficacy it's not a case of "this might work for you" it's "this will almost certainly work for you." It's cheap and it works.
Maybe for thinning hair only. If you're Norwood class 5–7, it won't help you unless you're a super responder (an outlier).
Yep, you have to start early; it regrows about 2-3 years of losses and prevents further losses.