The vial guide — what the label is telling you
Mass, volume and concentration explained on a made-up example vial, plus the words on a label: strength, freeze-dried powder, diluent, lot, expiry and storage. Preparation and dosing questions go to the label, a pharmacist or a prescriber. No doses.
Mass (mg or mcg)
How much of the substance there is. 1 mg is 1,000 mcg. A label strength like "10 mg" on a powder vial is a mass: the whole vial holds that much.
Volume (mL)
How much liquid there is. The final volume is all the liquid in the vial once the product is a solution, which is what a strength per mL is measured against.
Concentration (mg/mL)
Mass divided by final volume: how much substance is in each millilitre. It is the number that links an amount in mg to a volume in mL.
Strength
How much active ingredient the product contains, as printed on the label. Approved products state it in their prescribing information.
Lyophilised (freeze-dried) powder
Some injectable products are supplied as a dry powder because many peptides are more stable dry than in solution. The product's own instructions say whether and how it is prepared before use.
Diluent
The liquid a product's instructions name for preparing it, if it needs one. Bacteriostatic water contains a preservative; sterile water does not. Which one, if any, is set by the product's instructions, not by this site.
Lot number and expiry
Identify the batch and the date the manufacturer stands behind. Worth writing down in your own record when a product arrives.
Storage and in-use period
How the product is kept before and after first use, and for how long once opened or prepared. Both come from the label or leaflet and differ between products.
Read the label and leaflet
Approved medicines come with instructions for use. They are the reference for preparation, the liquid, storage and the device.
Ask a pharmacist or prescriber
Anything about preparing, measuring or giving a dose belongs with them. For an animal, ask your veterinarian.
If something looks wrong, stop
A damaged seal, an unexpected appearance, or a label that does not match what was prescribed is a question for the pharmacy that supplied it.
Dispose of sharps safely
Used needles and syringes go in a sharps container, never the household bin. Local rules and pharmacy take-back schemes vary, so check yours.
Educational use only, never medical advice. No doses.