Peptide, GLP-1 and TRT Glossary: Plain Definitions
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[Glossary · 50 terms]

Glossary

Mixing, measuring, injecting and tracking, in plain words · Reviewed

What this is: Short, sourced definitions of the words that come up when you mix, measure, inject and track peptides, GLP-1 medicines and testosterone. Each term says what it means, why it matters for your log, and shows a worked example where numbers are involved.

A to Z

Mixing and measuring

Vials, water, units and syringes.

Bacteriostatic water (BAC water)Bacteriostatic water (BAC water) is sterile water for injection with a small amount of benzyl alcohol… Concentration (mg/mL)Concentration is how much drug is in each unit of volume, usually written as mg/mL, mcg/mL or units/mL. It… Dead space (syringe)Dead space is the liquid that stays inside a syringe, in the hub and the needle, after the plunger is… DiluentA diluent is the liquid used to dissolve a powdered drug or thin a liquid one before it is injected. The… Insulin syringe unitsThe units on an insulin syringe are marks of volume. On a U-100 syringe, 1 unit = 0.01 mL; on a U-40… International unit (IU)An international unit (IU) measures a drug by its biological activity, compared with an agreed reference… Lyophilized (freeze-dried)Lyophilized means freeze-dried. The drug solution is frozen and the water is then removed, leaving a dry… mcg vs mg (micrograms and milligrams)mg (milligram) and mcg (microgram) are units of weight. One milligram is a thousandth of a gram; one… Needle gaugeNeedle gauge is a number for how thick a needle is. The scale runs backward: a higher gauge number means a… ReconstitutionReconstitution is adding a liquid, called a diluent, to a powdered drug so it dissolves into a solution… Sterile water for injectionSterile water for injection is sterile water with nothing added: no preservative, no antimicrobial agent… U-100 syringeA U-100 syringe is an insulin syringe marked for insulin that holds 100 units per mL. Each unit mark… U-40 syringeA U-40 syringe is an insulin syringe marked for insulin that holds 40 units per mL. Each unit mark equals…

How doses act in the body

Half-life, peaks, troughs and steady state.

BioavailabilityBioavailability is how much of a dose, and how fast, gets absorbed into the body where it can act. The FDA… Cmax (peak concentration)Cmax is the highest concentration of a drug measured in the blood after a dose. It is read straight from… Half-lifeHalf-life is the time it takes for the amount of a drug in your body to fall by half. After one half-life,… HematocritHematocrit is the percentage of your blood volume made up of red blood cells. A result of 45 means about… Loading doseA loading dose is a larger dose, or a short series of doses, given at the start of treatment to reach a… Steady stateSteady state is the point, after repeated doses on a fixed schedule, where the amount cleared between… Testosterone esterA testosterone ester is testosterone with a fatty acid chain attached, such as cypionate or enanthate. The… Titration (dose escalation)Titration means adjusting a dose in planned steps, usually starting low and going up, until a target or… Tmax (time to peak)Tmax is the time between taking a dose and reaching the highest drug level in the blood. It reflects how… Trough levelTrough level is the drug concentration at the end of a dosing interval, just before the next dose is due.… Washout periodA washout period is a stretch of time without a drug, long enough for the body to clear most of it before…

Injecting

Where and how shots go in, and what can go wrong.

Injection site reactionAn injection site reaction is any change at the spot where a shot went in: redness, swelling, itching,… Injection site rotationInjection site rotation means moving each injection to a different spot instead of using the same patch of… Intramuscular injection (IM)An intramuscular injection (IM) puts medicine deep into a muscle, below the fat layer. Most testosterone… LipohypertrophyLipohypertrophy is a rubbery lump of thickened fat under the skin that forms where injections are given… Subcutaneous injection (SubQ)A subcutaneous injection (SubQ) puts medicine into the layer of fat just under the skin, above the muscle.…

Protocol words

The shorthand people use to describe a plan.

Blend (peptide blend)A blend is a single vial that holds two or more peptides mixed together, such as BPC-157 with TB-500, or… Cycle (on/off cycling)A cycle is a planned stretch of taking a compound followed by a stretch off it, such as "8 weeks on, 4… Dosing frequency abbreviations (ED, EOD, E3.5D, QW, BID)Dosing frequency abbreviations are shorthand for how often a dose is taken. Some are old prescription… Microdosing (GLP-1 microdosing)Microdosing , for GLP-1 drugs, means taking much less than the label starting dose, or spacing doses… StackA stack is a set of two or more compounds taken over the same period, usually as separate shots or pills…

Compound types

What the drug classes are and how they work.

Amylin analogAn amylin analog is a man-made version of amylin, a hormone your pancreas releases together with insulin… Aromatase inhibitor (AI)An aromatase inhibitor (AI) is a drug that blocks aromatase, the enzyme that turns testosterone into… GIP (glucose-dependent insulinotropic polypeptide)GIP (glucose-dependent insulinotropic polypeptide) is a hormone released by K cells in the upper gut after… GLP-1 receptor agonistA GLP-1 receptor agonist is a drug that switches on the same receptor as GLP-1 (glucagon-like peptide-1),… Growth hormone secretagogueA growth hormone secretagogue is a compound that makes your pituitary gland release more of its own growth… PeptideA peptide is a short chain of amino acids, the same building blocks that make up proteins. US rules draw…

Quality, storage and rules

Testing, labels, compounding and handling.

503A vs 503B503A and 503B are two sections of US drug law that set the rules for compounding. A 503A pharmacy… Beyond-use date (BUD)A beyond-use date (BUD) is the date after which a compounded or opened medicine should not be used. It is… Certificate of analysis (COA)A certificate of analysis (COA) is a document listing test results for one batch (lot) of a product: what… Cold chainThe cold chain is the unbroken run of correct cold storage a temperature-sensitive medicine needs, from… Compounding pharmacyA compounding pharmacy makes a medicine from raw ingredients for a specific patient, rather than… EndotoxinEndotoxin is a substance from the outer wall of certain bacteria (gram-negative bacteria), released when… HPLC purityHPLC purity is the percent of a sample that is the intended compound, measured by high-performance liquid… Mass spectrometry (MS)Mass spectrometry (MS) is a lab method that weighs molecules. It turns molecules into charged particles… Multi-dose vialA multi-dose vial holds more than one dose and is made to be entered more than once. CDC says that once… Research use only (RUO)Research use only (RUO) is a label phrase. In US rules it comes from labeling for in vitro diagnostic…

Frequently asked questions

Who writes these definitions?+
The Dose Track team writes them from FDA labels, government pages and published studies, which are listed at the bottom of each term. They are reviewed when the sources change.
Is this medical advice?+
No. The glossary explains words and numbers so labels and studies are easier to read. Decisions about what to take and how much belong with your prescriber.
What is the difference between mg, mcg and units?+
Milligrams and micrograms measure the drug itself (1 mg = 1,000 mcg). Units on an insulin syringe measure liquid volume (on a U-100 syringe, 100 units = 1 mL). To turn units into a dose you need the concentration of the vial.

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