When I was getting started I was so confused about buying syringes. I got a lot of help from others in this forum and I wanted to put it all here for my reference, and possibly for anyone else that might be confused.
You’re looking for disposable insulin syringes. These are so cheap there’s no point not to get a bunch of them so you never have to reuse, share, use expired syringes, etc. You can get 100 for as cheap as $15, which would last more than 3 months even if you dosed every day.
There’s 3 numbers when it comes to purchasing syringes:
Gauge
You have the option of 28, 29, 30 and 31 gauge needles. The higher numbers mean smaller width. So to minimize pain you want the highest gauge needle available, in this case 31g.
CC / ML
The next number measures how much liquid the syringe will hold. 1 CC is equal to a cubic centimeter, or 1 ml. In America the syringes will be measured in CC's, but if you're buying them in Europe (and most places), they'll be measured in ml. For example 3/10 CC would be 0.3ml, and 1/2cc would be 0.5ml, etc.
You want a relatively smaller size because it helps you measure the small doses needed for melanotan. Because of the doses we're using, 1/2cc (0.5ml) or 1cc (1 ml) sized syringes would probably be best so you can easily measure out ½ - 2 ml.
I got 3/10cc as it’s the smallest and thought it'd be less intimidating but I didn’t fully understand it can only hold 0.3 ml at a time, which means that it's a huge pain to measure out 1 ml for reconstitution! Next time I'll probably get 1/2cc (0.5ml) size.
Length of Needle
The last number is the length of the needle. When searching for syringes you want a shorter needle (no need to for a long needle with melanotan). The epidermal layer, and subcutaneous space (where you're aiming for) are around 6mm deep, so as low as 5/16" (8mm) needles are fine if you're inserting all the way. You have the option of 1/2” (12.7mm) but I chose the smaller 5/16” (8mm) length needle since it’s the least scary looking.
Summary:
Next time I think I'd get these:
31G 1/2cc 5/16" Disposable Syringes <--- America
31G 0.5ml 8mm Disposable Syringes <--- Everywhere else
Am I missing anything? Does anyone have anything to add?
Edit: Added extra information provided by Peptide Guru about sizes outside of America.