You asked the right and most important question first. What is the amount of drug in a vial or a kit.? When you are dosing yourself as opposed to getting a prescription for a drug from a doctor, there is no one there to stop you from making mistakes, getting the dose wrong by a factor of ten or two is super easy and happens all the time, and you would have to be incredibly unlucky to get killed by it , but you would have a good chance of a very bad time of vomiting for a week or some similar unpleasant experience.
Do lots of reading of other peoples experiences, doses , side effects etc. Always double and triple check calculations of doses and dilutions. If you buy more than one different peptide label them carefully so you cannot mix them up. Buy from popular vendors that show test results. Good luck, read lots and ask stupid questions, much safer than not asking them.