Peptide tracking glossary

Bacteriostatic water

Sterile water containing a small amount of preservative, usually 0.9% benzyl alcohol, that inhibits bacterial growth. It is one of the liquids commonly used for reconstitution.

Concentration

The amount of substance in each unit of liquid, usually written as mg/mL or mcg/mL. Concentration equals the vial strength divided by the volume of liquid added: 5 mg in 2 mL is 2.5 mg/mL.

CSV file

Comma-separated values: a plain-text file of rows and columns that opens in any spreadsheet. PepVault exports dose history as CSV.

Dose log

A dated record of each dose: what, how much, when, where and any notes. Also called a dose history or injection log.

Expiration date

The date printed on a product after which it should not be used. A reconstituted vial usually has a shorter usable period than the sealed one; follow the label or your pharmacist.

GLP-1 receptor agonist

A class of prescription peptide medicines, including semaglutide and tirzepatide (a dual GIP/GLP-1 agonist), usually injected once a week. Users often track dose dates, sites and weight alongside them.

Injection site rotation

Using a different site for each injection in a planned pattern rather than the same spot repeatedly. A site log records where each one went.

International unit (IU)

A measure of biological activity, defined separately for each substance. IU cannot be converted to mg or mcg without the conversion factor for that specific substance, and it is different from the unit marks on a syringe.

Lot number

The manufacturer's code identifying the production batch a vial came from. Recording it lets you tie a log entry to a specific batch.

Lyophilised powder

A freeze-dried powder. Many peptides are supplied this way in sealed vials because the dry form is more stable than a solution.

Microgram (mcg)

One millionth of a gram and one thousandth of a milligram. 1 mg equals 1,000 mcg. Also written µg.

Milligram (mg)

One thousandth of a gram. 1 mg equals 1,000 mcg.

Millilitre (mL)

A unit of volume, one thousandth of a litre. 1 mL is the same volume as 1 cc and equals 100 units on a U-100 syringe.

Peptide

A short chain of amino acids, the same building blocks that make up proteins. Peptides are generally defined as chains of roughly 2 to 50 amino acids; longer chains are called proteins.

Peptide tracker

An app or log used to record peptide doses, vials, injection sites and schedules. PepVault is a peptide tracker for Android, iPhone, iPad and Mac.

Reconstitution

Adding a measured volume of liquid to a dry (lyophilised) powder so it can be drawn into a syringe. The amount of liquid added sets the concentration of the solution.

Subcutaneous injection

An injection into the layer of fatty tissue just under the skin, commonly in the abdomen or thigh.

Syringe units

The graduation marks on an insulin syringe. On a U-100 syringe they measure volume only: 10 units is 0.1 mL. They are not the same thing as international units (IU).

U-100 insulin syringe

A syringe graduated so that 100 units equal 1 mL. Each unit mark is 0.01 mL. Common sizes are 1 mL (100 units), 0.5 mL (50 units) and 0.3 mL (30 units).

Vial strength

The total amount of substance in a vial, as printed on the label, for example 5 mg or 10 mg.

Definitions are general and for reference. They are not medical advice.