Can you explain how metformin is supposed to help? And NMN (maybe start by defining it, as I've never heard of it)?

NMN (Nicotinamide Mononucleotide) is believed to raise levels of NAD+, which in turn is a vital component of mitchondrial energy production (and levels tend to fall with age).

I'm actually taking plain Nicotinamide (one form of Vitamin B3) in larger amounts (3g/day) and the benefits I feel from it are similar to those ascribed to NMN (the recommended dose of which is about 1g/day).

Metformin has a pretty bad side effects with low term use, induced Vitamin B deficiency being the notable.

The major problems with Metformin are that it frequently makes people nauseous, it causes sperm damage in men (effects go away when you cease taking it + about 3 months), and in rare cases can cause lactic acidosis if you consume alcohol.

Admittedly, I got put on it because my blood work wasn't going in the right direction, but it has noticably increased my ability to lose weight. Not exactly scientific, but in my first 5 months of trying to lose, I was down 30 pounds, in the next 5 months after starting it, I lost about 50 and was less strict about my diet...

Now I'm down a full 100.