Terms in plain language

Agonist

A compound that binds a receptor and activates it. An antagonist binds and blocks it.

Amino acid

The building block of peptides and proteins. Twenty are standard in human biology.

Analog

A modified version of a natural molecule, usually changed to last longer or bind more selectively.

Bacteriostatic water

Sterile water with 0.9% benzyl alcohol, which inhibits bacterial growth in multi-use vials.

Bioavailability

The fraction of a compound that reaches circulation. Oral peptides often have low bioavailability because they're digested.

Certificate of analysis (COA)

A lab report for a specific lot showing identity and purity, typically by HPLC and mass spectrometry.

Half-life

Time for the concentration of a compound to fall by half.

HPLC

High-performance liquid chromatography, the standard test for purity.

In vitro / in vivo

In vitro: studied in cells or tissue outside an organism. In vivo: studied in a living organism.

Lyophilized

Freeze-dried into a powder for stability. Reconstituted with a diluent before use.

Mass spectrometry (MS)

Confirms a compound's identity by its molecular weight.

mcg / mg

Microgram and milligram. 1 mg = 1,000 mcg.

Peptide

A short chain of amino acids, generally under about 50. Longer chains are proteins.

Pharmacokinetics

How a compound is absorbed, distributed, metabolized, and cleared.

Preclinical

Research done before human trials: cell and animal studies.

Reconstitution

Dissolving a lyophilized powder in a diluent to make a solution.

RUO

Research use only: not approved for human or veterinary use.

Subcutaneous / intramuscular

Into the fat layer under the skin / into muscle. Routes used in research models.

U-100

Syringe scale where 100 units = 1 mL.