Is there any side effects to this stuff?
Depends on the fellow. Finasteride, I started at 26 (I'm 36 now), and initially and taking it once a day every day I had a decrease in libido which is the biggest thing most people notice. It can make you a bit more cranky/less patient/more aggressive and if anyone is depressed I'd say it could tilt the scales into further depression, if you're paranoid, the same thing.
These weren't too bad for me and aren't for most people that don't have a pre-existing tendency for any of those. After a few months you adjust and function just the same as before, the side effects effectively gone. Regardless, as I said I prefer to function with a bit less finasteride than what's prescribed if you just want to maintain. For the first month to an year you probably can't avoid normal dosage (1 mg per day). Some people like to buy proscar, which is for same substance (but with 5 times the dosage with 5 mg and that way they can take a bigger dosage. I don't recommend it, but doable.
Minox/Rogaine, I never used, but it can hit skin fairness, you can get acne, some rashes kinda as if it was abrasive. It's also supposed to have a specific smell, and you have to sleep with it applied. A bit unpractical.
Happens to us all, but I've always been a little confused about hair loss. Is there an ACTUAL way to stop it such as catching it early or suitable treatments?
Finasteride will do that for most people.
If I started at 22 or something, I would have all my hair. Thing is at first you don't notice you're thinning because all your hair is there, just experiencing minification (hair width getting smaller)
You can still lose some, as it only decreases in 70% what causes male pattern hair loss (it's DHT), but it should be enough to keep everything, yes.
Most people taking finasteride stagnate or almost stagnate. In my case it 100% stagnates.