Glossary - Peptigraph

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Acetic acid water (0.6%): Sterile water with 0.6% acetic acid. ONLY for the few peptides that will not dissolve otherwise, because they need an acidic environment. Never use it as a substitute for BAC water or sterile water - it is unsuitable for all other compounds.; Also called acetic acid water, acetic acid 0.6%, acetic acid
Agonist: A substance that binds a receptor and activates it - triggering its signal. Many peptides act as agonists, e.g. GLP-1 agonists.; Also called receptor agonist, agonists
Analogue: A slightly modified version of a natural molecule. Small changes can boost potency or extend how long it acts.; Also called analog, analogues, derivative
Antagonist: A substance that binds a receptor but does not activate it - blocking the normal signal. The opposite of an agonist.; Also called receptor antagonist, blocker, antagonists

Bacteriostatic water (BAC water): Sterile water with 0.9% benzyl alcohol. The additive inhibits microbes, so a mixed solution stays usable for several weeks in the fridge.; Also called bac water, bacteriostatic water, benzyl alcohol water
Bioavailability: The fraction of a drug that actually reaches the bloodstream unchanged. It explains why many peptides are injected rather than swallowed.; Also called availability, bioavailability, F

Certificate of Analysis (CoA): A lab report on a batch's identity and purity - usually by HPLC and mass spectrometry. Meaningful only when it independently tests the product you received.; Also called CoA, certificate of analysis, lab report
Cold chain: The unbroken refrigeration of sensitive substances from manufacture to use. Gaps (e.g. long warm shipping) can reduce potency.; Also called cold chain, refrigerated, cold storage, storage
Cycling: Using something in phases - an „on" period followed by an „off" break. A common aim is to prevent a fading effect (tolerance).; Also called cycle, on/off, course

Dead space: The small amount of liquid that stays in the needle and syringe hub and is not injected. With very small doses this can matter.; Also called dead volume, residual volume

Evidence level: How well a claim is backed by studies. Data from large human trials carry more weight than animal or lab work or mere anecdotes.; Also called level of evidence, evidence grade, strength of evidence

Grey market / Research chemical: The sale of substances outside regular drug approval, often labelled „for research only". Such labels dodge regulation and say nothing about quality.; Also called research chemical, RC, grey market, not for human use, for research only

Half-life: The time it takes for half of an active substance to be broken down or cleared from the body. It drives how long a peptide acts and how often it is used.; Also called half-life, t½, elimination half-life
HPLC / HPLC-MS: Lab methods that separate and identify a sample's components. HPLC measures purity; coupled with mass spectrometry (MS) it also confirms identity.; Also called HPLC, HPLC-MS, LC-MS, high-performance liquid chromatography

Insulin syringe (U-100): A fine syringe with a fixed needle, scaled in „units". On a U-100 syringe, 100 units equal exactly 1 ml - the usual syringe for subcutaneous peptide doses.; Also called U-100, U100, insulin needle, units
Intramuscular (i.m.): An injection directly into a muscle, using a longer needle. Less common than subcutaneous for peptides, but used in some cases.; Also called i.m., im, into the muscle, intramuscular

Lyophilizate: A freeze-dried powder. Peptides are lyophilized because, as a dry powder, they stay stable and usable far longer than in solution.; Also called lyophilized, freeze-dried, dry powder

Maintenance dose: The stable dose you settle on after ramping up. Some protocols start with a higher „loading" phase, then drop to the maintenance dose.; Also called maintenance, target dose, steady dose
Microdosing: Deliberately starting with a dose well below the usual standard or manufacturer recommendation, to first test your own reaction and tolerability and work up only in small steps ("start low, go slow").; Also called micro-dosing, micro dosing, microdose

Off-label: Using an approved medicine outside its official approval - e.g. for a different indication or dose than the one tested.; Also called off label, off-label use, beyond approval

Partial agonist: A substance that only partly activates a receptor - weaker than a full agonist, but more than nothing.; Also called partial agonist
Pharmacokinetics & dynamics (PK/PD): Two viewpoints: pharmacokinetics = what the body does to the substance (absorption, distribution, breakdown); pharmacodynamics = what the substance does to the body (effect).; Also called PK, PD, PK/PD, pharmacokinetics, pharmacodynamics
Purity (%): The fraction of the desired substance in a sample, usually a percentage by HPLC. High purity says nothing about the correct amount in the vial.; Also called purity, purity grade, percent pure

Receptor: A docking site on or in a cell that a messenger binds to, triggering a signal inside the cell. Agonists and antagonists act through receptors.; Also called binding site, docking site, receptor
Receptor desensitization: When a receptor becomes less responsive from constant overstimulation, or the cell reduces its receptors - the same dose then works less.; Also called downregulation, tolerance, desensitisation
Reconstitution: Mixing a freeze-dried peptide: you add a sterile liquid (usually bacteriostatic water) to the vial until the powder is fully dissolved and an injectable solution forms.; Also called mixing, dissolving, reconstituting

Secretagogue: A substance that prompts the body to release its own hormone - rather than supplying the hormone itself. Many GH peptides are growth-hormone secretagogues.; Also called secretagogue, releaser
Sterile water for injection: Germ-free water with no additive. It works for mixing but offers no preservation - the solution should be used promptly.; Also called water for injection, WFI, sterile water
Subcutaneous (s.c.): An injection into the fatty tissue just under the skin (between skin and muscle) with a short, fine needle. The most common route for peptides.; Also called s.c., sc, subq, SubQ, under the skin

Titration: Easing up to the target dose: start low and increase slowly so the body can adapt and side effects stay smaller.; Also called dose ramp, titrating up, titration

Units: IU, mg, mcg: mg (milligram) and mcg/µg (microgram) are masses; 1 mg = 1000 mcg. IU (international unit) measures effect, not mass - the two must not be equated.; Also called IU, mg, mcg, µg, microgram, milligram, international unit

Vial: The small glass bottle with a rubber stopper that the peptide powder ships in. You draw through the stopper without removing it.; Also called glass vial, bottle, vials