Glossary

Amino Acid: An organic molecule that serves as a building block of peptides and proteins. Peptides are defined by the length and sequence of the amino acid chain that makes them up.
Bacteriostatic Water (BAC Water): Sterile water containing 0.9% benzyl alcohol as a preservative. The standard diluent for reconstituting lyophilized peptides, since the preservative allows a vial to be punctured repeatedly over roughly 25–30 days without significant bacterial growth.
Concentration: The amount of peptide dissolved per unit volume of solution after reconstitution, expressed as mg/mL. Determined entirely by how much diluent is added to the vial.
Diluent: The liquid used to dissolve lyophilized peptide powder. Bacteriostatic water is the standard choice; sterile water and normal saline are used in specific contexts but lack a preservative.
Half-Life: The time required for half of a substance to be cleared from the body or lose biological activity. Half-life is a major factor in how often a peptide is administered.
IU (International Unit): A unit of measurement for biological potency, not weight. Used for a small number of compounds — notably growth hormone and HCG — where potency has been standardized through bioassay rather than measured directly by mass. Not interchangeable with syringe units.
Lyophilization (Freeze-Drying): The process of removing water from a substance by freezing it and reducing pressure so the ice sublimates directly to vapor. Produces the stable, dry powder form in which peptides are typically supplied.
mcg (Microgram): A unit of weight equal to one-thousandth of a milligram. 1 mg = 1,000 mcg. Many peptides are dosed at the microgram scale.
mg (Milligram): A unit of weight equal to one-thousandth of a gram. Used to describe both total vial content and per-dose amounts.
mL (Milliliter): A unit of volume equal to one-thousandth of a liter. On a U-100 insulin syringe, 1 mL equals 100 units.
Peptide: A short chain of amino acids linked by peptide bonds, generally in the range of 2 to 50 amino acids. Chains longer than that are typically classified as proteins.
Potency: The measure of a substance's biological activity relative to its weight. Potency can decline through degradation even when the nominal weight of powder in a vial stays the same.
Reconstitution: The process of dissolving lyophilized peptide powder in a liquid diluent to create a solution that can be measured and drawn into a syringe.
Sharps Container: A puncture-resistant container designed for the safe disposal of used needles and syringes.
Sterile Water: Water that has been sterilized but contains no preservative. If used as a diluent instead of bacteriostatic water, the resulting solution has a much shorter usable window, typically 24–48 hours.
Subcutaneous (SubQ / SC): An injection route delivering a substance into the fatty tissue layer just beneath the skin. The most common administration route referenced in peptide research protocols.
Syringe Units: The volume markings on an insulin syringe barrel. On a U-100 syringe, 100 units equal 1 mL, so each unit represents 0.01 mL. Purely a measure of volume, unrelated to International Units.
Titration: The practice of gradually adjusting a dose, typically starting low and increasing incrementally, to identify an effective amount while limiting side effects.
U-100 Syringe: An insulin syringe calibrated so that 100 unit markings equal 1 mL of liquid (1 unit = 0.01 mL). The most common syringe type referenced in peptide dosing protocols, available in 0.3 mL, 0.5 mL, and 1 mL barrel sizes.
Vial: A small sealed glass container holding lyophilized peptide powder, closed with a rubber stopper and aluminum crimp cap. The label states the peptide name and total content by weight.