Glossary

The building blocks of peptides and proteins. The specific sequence of amino acids determines a peptide's function.

Sterile water containing 0.9% benzyl alcohol as a preservative. It inhibits bacterial growth, allowing a reconstituted vial to be used over multiple doses.

A compound a 503A/503B pharmacy may legally prepare with a prescription.

How much peptide is contained per unit of liquid, usually expressed as mg/mL. Calculated as total peptide mass ÷ volume of water added.

The amount of reconstituted solution you pull into the syringe to deliver a target dose. Equals target dose ÷ concentration.

A rating (A–D) summarizing how much human clinical evidence supports a compound, from large trials (A) to preclinical only (D).

Growth-Hormone-Releasing Hormone analog. Stimulates the pituitary to release growth hormone (e.g., CJC-1295, Sermorelin).

Growth-Hormone-Releasing Peptide / ghrelin mimetic. Amplifies GH pulses through a different receptor than GHRH (e.g., Ipamorelin, MK-677).

A compound that activates the GLP-1 receptor to reduce appetite and improve glucose control (e.g., Semaglutide, Tirzepatide).

The time it takes for half of a compound to be cleared from the body. Longer half-lives mean less frequent dosing and more stable blood levels.

High-sensitivity C-reactive protein — a blood marker of systemic inflammation often tracked during healing protocols.

Insulin-like Growth Factor 1. The primary downstream marker used to gauge the effect of growth-hormone peptides.

A syringe marked in units where 100 units = 1 mL. Widely used for peptide dosing because the fine markings allow precise small volumes.

Injection directly into muscle tissue, used for some compounds like HCG.

Administration as a nasal spray, used for peptides like Selank and Semax.

Freeze-dried into a stable powder. Most research peptides ship lyophilized and must be reconstituted with liquid before use.

One millionth of a gram. 1000 mcg = 1 mg. Many peptides are dosed in mcg.

One thousandth of a gram. Vial sizes are usually labeled in mg (e.g., a 5 mg vial).

A short chain of amino acids (typically 2–50) linked by peptide bonds. Peptides act as signaling molecules that tell cells what to do.

A combination of two or more peptides used together, ideally chosen so their mechanisms complement rather than conflict.

The process of dissolving lyophilized peptide powder into a liquid (usually bacteriostatic water) to create an injectable solution.

Not approved for human use; available only as a research chemical.

Water with no preservative. Suitable only for single-use because it offers no protection against bacterial growth once the vial is opened.

Injection into the fatty layer just under the skin — the most common route for peptide research.

When two peptides produce a greater combined effect than either alone — e.g., a GHRH + GHRP pairing amplifying GH release.

Gradually increasing a dose over time to reach a target while minimizing side effects — common with GLP-1 compounds.

Applied to the skin, used for compounds like GHK-Cu in cosmetic/skin contexts.

The markings on a U-100 insulin syringe. 10 units = 0.1 mL, 50 units = 0.5 mL, 100 units = 1 mL.