Here's some stolen info that seems commonly used. I've started some MT2 myself and have some info on how I'm running it in my log. There's also info in the Labpe stickies.
Melanotan 2 Dose
:Starting dose: Your first injection should be a very small dose, for example .25mg (250mcg). See how you react. Goal should be to feel nothing. Dose after dinner, before bed. Any dosing chart stating that you should take a high dose (according to your weight) is outdated and potentially dangerous.
Loading dose: Load with 0.5-1mg once a day. People who have used doses in this range generally report getting excellent results. Don’t worry if you miss occasional days. It will not make much difference, focus on the cumulative effects.
Maintenance dose: Maintenance is taking doses less frequently than daily to avoid becoming darker than you want. Yes, that will happen. With enough UVR, you will get much darker than you have even been before. A maintenance dose can help prolong super-physiological photo-protection MT-2 delivers.