Sounds like yes, you have 10x40mg vials. 40mg is a lot of GLP unless you're running the very top-end dose of like 10-12mg per week. There is not a ton of good data on the rate of degradation of the GLP meds once reconstituted (that is, after you mix them with the bacteriostatic water that you presumably purchased with your peptide) but I have heard three weeks is a good ballpark. Others claim they are good to go for as long as 2-3 months if kept under refrigeration once reconstituted. I usually try to get through my vials within 2-3 weeks, which means I usually buy 10 or 20mg vials. That said, when I have purchased 30mg vials in the past and used them at lower doses, so they last 2-3 months, I can't say I have experienced a drop in efficacy over time.

Keep your unconstituted peptides in the freezer, as they will last longer, and definitely don't reconstitute more than 1 vial at a time! At that concentration, you could reconstitute with 4ml, so one unit (.1ml) would be 4mg, or if you are dosing lower .05ml would be 2mg. If you plan on doing a true microdose of like 1mg then you might want to reconstitute with more, but my guess is your vials are the little 3ml so you might not be able to get 4ml in there.

Good luck!

40mg per vial. google a peptide reconstitution calculator if you haven't so you don't fuck up the measurements and do some more research.