[Question] does needle dead space actually matter at 2.5mg doses
Question in the title, detail here: does needle dead space actually matter at 2.5mg doses.
Numbers, in the order they matter: 2.5mg.
I keep a laminated card in the drawer with the arithmetic on it. Looks ridiculous. Has never once let me draw the wrong volume.
Spent 22 weeks confused about this until somebody drew the table for me. 5mg, 1mL, 5mg/mL, 2mg is 40 units. That is the whole thing.
If somebody has the same thing measured a different way, post it next to mine and we will see whether they agree.
best — the order this archive was captured in
Why "more water" keeps confusing people, including me for a month.
The vial contains a fixed amount of peptide. Water changes nothing about that amount. What it changes is concentration, and concentration is the divisor between the dose you want and the volume you draw.
So doubling the water halves the concentration and doubles the units for the same dose. Nothing is diluted in any sense that matters; you are simply reading a bigger number off the same barrel. Pick the water volume that puts your usual dose on a whole number of units and life gets easier.
Reminder: this board does maths, not dosing. Nobody here tells another member what amount to take.
Bacteriostatic or plain sterile water?
the powder cake sits at the bottom, the volume you add is the volume that counts
Small fix — a U-100 syringe is 100 units per mL. If yours is marked differently it is not U-100 and the whole calculation changes.
Agreed on the swirl. There is no reason to shake it and a good reason not to.
Is that a U-100 syringe? The barrel markings change the answer completely.
reconstituting at a round concentration makes every later dose easy
Show the arithmetic — where did the unit figure come from?
The arithmetic in full: concentration is mass over volume, so 30mg into 3mL gives 10mg/mL. A U-100 syringe is graduated at 100 units per millilitre, so 5mg is 5 divided by 10 millilitres, which is 50 units.
What is written on the vial right now?
Adding more water does not change how much peptide is in the vial. It changes the concentration, which changes the volume you draw for the same amount. That is the entire relationship.
Shook the first vial because nobody told me not to. It was fine, but I have swirled every one since.
Shook the first vial because nobody told me not to.
mateusz_achebe has the units point exactly right. They are a volume on the barrel and nothing else.
Started reconstituting everything to a round concentration and the six-in-the-morning error rate went to zero.
I would not round that figure. At 6.67mg/mL a rounding error of two units is a real fraction of the intended amount.
Asked JEEP what volume they reconstitute to for their own stability testing and they answered in one line. Useful thing to know.
How many mg in the vial and how many mL are you adding?
What concentration did you actually reconstitute at, rather than what did you intend to?
30mg into 3mL is 10mg/mL, and 2.5mg of that is 25 units
- 1Reminder: this board does maths, not dosing. Nobody here tells another…9 comments in this branch · started by u/units_not_mg