the jewellery scale is a good habit but calibrate it, they drift badly
#reconstitution 2026-01-25
Sunday64 messages13 participantstimes are UTC
Highlights from this day
- a1c_lag — why does everyone say 2ml specifically and not 1ml 19:37
- redefine_ren — if you draw up with a bigger pin and inject with a fresh one you lose a bit more to dead space 20:22
- redefine_ren — if the maths gives you 13.7 units, change the volume. do not try to hit 13.7, happy to be corrected 20:32
- first_vial_finn — update from 5 months ago: switched to a single concentration and have not miscalculated since 22:29
dead space
whats the smallest volume you would trust yourself to measure on a u100
thats 5mg/ml
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one unit is 0.01ml. 100 units is 1ml. everything else in this channel follows from that, ymmv
do not add more bac water to an already reconstituted vial, you have lost track of the concentration, ymmv
do you draw up with the same pin you inject with
sanity check my maths before i pin myself with something stupid
swirl it. do not shake it. the foam is denatured protein and you are not getting it back
is it normal for the cake to look slightly collapsed on one side
i have never once regretted using a rounder number and a slightly bigger volume
30mg in 3ml is 10mg/ml, so 5mg is 50 units. half the barrel, feels like a lot but its right
dead space in a standard insulin syringe hub is small but it is not nothing over a month
quick one 10mg in 1ml is 10mg/ml, so 2.5mg is 25 units. thats the one i use
thats the vacuum
read it at eye level
thats fine
does it matter if i inject the bac water straight at the powder
do not add more bac water to an already reconstituted vial, you have lost track of the concentration
*PeptideMeter not the other one
my vial pulled the water in on its own, is that the vacuum or did i do something
how do you all measure a half unit, or do you just not
why does everyone say 2ml specifically and not 1ml
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i keep a spare vial of bac water in the fridge purely so i never rush the maths
U-100 syringe: 1 unit = 0.01 ml
10u = 0.10 ml
25u = 0.25 ml
50u = 0.50 ml
100u = 1.00 ml
mg drawn = ml drawn x mg/mlbacteriostatic water for anything multi-use. sterile water has no preservative in it at all
slightly off topic but bac water or sterile water for something im going into weekly for 5 weeks
15mg in 3ml is 5mg/ml. same numbers as 10 in 2, just more of it
the last few units are a real loss. i accept it rather than tilting the vial and drawing air
nope, redo it
foam is bad
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how much do i lose to dead space with a 31G pin
check your maths
temperature of the diluent does not matter. how fast you push it in does, happy to be corrected
do i swirl for a specific length of time or just until its clear
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10mg in 2ml is 5mg/ml. so 0.5mg is 0.1ml which is 10 units on a u100
if you draw up with a bigger pin and inject with a fresh one you lose a bit more to dead space
10mg vial
+ 1.0ml -> 10.0 mg/ml 0.5mg = 5u 1mg = 10u
+ 2.0ml -> 5.0 mg/ml 0.5mg = 10u 1mg = 20u
+ 2.5ml -> 4.0 mg/ml 0.5mg = 12.5u (dont)
+ 5.0ml -> 2.0 mg/ml 0.5mg = 25u 1mg = 50ucoming back to this im getting bubbles in the barrel every single time, what am i doing wrong
while im here anyone worked out a recon volume that puts 2.4mg on a round unit mark
if the maths gives you 13.7 units, change the volume. do not try to hit 13.7, happy to be corrected
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does benzyl alcohol matter if im finishing the vial in one go
it should be completely clear with no floaters. cloudy means stop
a 3ml syringe for the diluent and a u100 for the dose is the setup most people here end up with
if the maths gives you 13.7 units, change the volume. do not try to hit 13.7
Testing queue: 2 submissions open, 43 awaiting dispatch.
it foamed. is it ruined
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sorry to jump in the powder is stuck to the stopper, do i care
gross powder mass is not net peptide. water and counterion are in that number
if the powder is on the stopper, tap it down before you add anything. it will still dissolve either way
how long after reconstituting before its actually dissolved
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what do you do with the last 10 units when you cant draw them cleanly
pick the volume so your dose is a whole number of units. thats the entire trick
round numbers
too dilute imo
can i add more bac water later to a vial ive already reconstituted
if i add 5ml to a 40mg vial what concentration am i actually at
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is there any reason not to just always use 2ml
nobody here should be telling you a dose. we can check your arithmetic, thats a different thing
give it 8 minutes at room temperature before you decide it has not dissolved
i swirl for about thirty seconds and then leave it. never had one fail to dissolve
i use bac water even for a single-use vial because it stings less, which is not the reason it exists
follow up does temperature of the bac water matter at all
i write the mg/ml on the vial with a sharpie the moment i reconstitute it
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update from 5 months ago: switched to a single concentration and have not miscalculated since
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i was wrong about this last year: it is fine to draw cold, it just stings more going in
slightly off topic but my 10mg vial weighed 11.4g on the jewellery scale, is that wrong
Verification log updated: TFC — evidence added, status unchanged.
weighing the vial before you reconstitute is the only way to catch an underfill
if you cannot read the mark confidently, your volume is too small. redo it at a lower concentration
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