You don't need methylene blue. You can fix your mitochondria by doing HIIT. I've done it and it works.
Absolutely you can. Doing high intensity training is WAY more important than any kind of supplement. MB is just a useful addition. Definitely not necessary
Anyone who thinks they can replace movement with supplements is a complete idiota
Well... That's something my parents need to hear. They eat more pills than food, and think riding their e-bikes is exercise.