Glossary
The words that trip everyone up.
Plain-English definitions for the terms you’ll actually see on a vial, a forum, or a doctor’s note. Observational, not prescriptive.
- Prep
Reconstitution
Mixing a dry powder peptide with sterile water so it can be drawn into a syringe.
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- Prep
Bacteriostatic water
Sterile water with a preservative that keeps a mixed vial usable for a few weeks.
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- Route
Subcutaneous
Injected into the fat layer just under the skin. Short needle, shallow angle.
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- Route
Intramuscular
Injected into muscle tissue. Longer needle, common for TRT.
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- Protocol
Stack
The full set of compounds you're running at the same time.
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- Protocol
Cycle / off-cycle
A stretch of weeks on a compound, followed by a stretch off to give your body a break.
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- Protocol
Titration
Easing a dose up or down gradually over weeks, rather than jumping straight to a target.
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- Measurement
IU (International Unit)
A dose unit used for some peptides. Not the same as milligrams.
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- Measurement
U-100 syringe
An insulin syringe marked 0 to 100 units. One unit equals 0.01 mL.
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- Measurement
mcg vs mg
1,000 micrograms (mcg) equals 1 milligram (mg). Easy to misread on a label.
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- Protocol
GLP-1 agonist
A class of drugs (semaglutide, tirzepatide) that mimic a gut hormone tied to appetite.
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- Timing
Half-life
How long it takes for half of a dose to clear your system. Drives dosing frequency.
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- Protocol
Peptide
A short chain of amino acids. Smaller than a protein, larger than a single amino acid.
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- Protocol
Ancillary
A supporting compound taken alongside a main one, often to manage side effects.
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- Timing
Loading dose
A larger starting dose some protocols use to reach steady levels sooner, before settling to a maintenance amount.
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- Timing
Trough
The lowest level of a compound in your system, right before the next dose.
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New to this?
Start with the beginner’s guide.
A calm walkthrough of peptides, GLP-1s, and TRT, plus a reconstitution calculator you can actually use.
Read Start here