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c/reconstitution·submitted 10 months ago by u/aurel_boateng

mg/mL is the most under-discussed thing on this board

Correctionbranch of 7 comments

mg/mL is the most under-discussed thing on this board. Not a hot take, just something I have not seen said plainly here. 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. Why "more…

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7 comments, started 10 months ago
u/sigrid_kaufmann227 points·10 months ago

If your calculation produces a fraction of a unit, the concentration is wrong for your dose. Change the water volume until the numbers land on whole units.

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u/swirl_dont_shakereconstitution77 points·10 months ago

Shook the first vial because nobody told me not to. It was fine, but I have swirled every one since.

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u/aurel_boatengOP31 points·10 months ago

Did the maths give you a whole number of units, or a fraction?

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u/karim_ilunga21 points·10 months ago

swirl, never shake

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u/saskia_mwangi8 points·10 months ago

The arithmetic in full: concentration is mass over volume, so 10mg into 1mL gives 10mg/mL. A U-100 syringe is graduated at 100 units per millilitre, so 2.5mg is 2.5 divided by 10 millilitres, which is 25 units.

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u/yusuf_achebe155 points·10 months ago

Is that a U-100 syringe? The barrel markings change the answer completely.

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u/ines_lindqvist34 points·10 months ago·edited

That only works if the fill weight is exactly the label weight, and it usually is not exactly anything.

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