Peptide glossary: 14 terms explained (2026)

The vocabulary used across the directory — what a COA is, what HPLC measures, what lyophilized means and how price per mg is worked out.

PWBy PeptideTech EditorsReviewed Sep 16, 2026Prices checked weeklyHow we verify →

Certificate of analysis (COA): A laboratory report covering one production lot of a compound. It states the lot number, test date, purity as a percentage of HPLC peak area, the identity result from mass spectrometry, and the laboratory that ran the tests. A COA that does not name a lot number cannot be tied to the vial you received.
HPLC: High-performance liquid chromatography, the standard method for measuring the purity of a peptide sample. The result is reported as the percentage of total peak area belonging to the target compound; research vendors typically state 98% or higher.
LC-MS: Liquid chromatography paired with mass spectrometry. Chromatography separates the components of a sample and mass spectrometry measures their molecular weight, which confirms that the compound in the vial is the one on the label.
Lyophilized: Freeze-dried. Peptides are supplied as a lyophilized powder in a sealed vial because the dry form is stable at ambient temperature during shipping and can be stored frozen for long periods.
Reconstitution: Dissolving a lyophilized powder in a solvent, normally bacteriostatic water, to produce a solution of known concentration in milligrams per millilitre. The reconstitution calculator returns that concentration and the volume of a draw.
Bacteriostatic water: Sterile water containing 0.9% benzyl alcohol as a preservative. It is the solvent research vendors list for reconstituting lyophilized peptides, and it is sold in 10 mL and 30 mL vials.
Research use only (RUO): A designation meaning a product is sold for laboratory research and is not approved as a drug, food or supplement. Every product listed on PeptideTech is research use only and not for human consumption.
Price per mg: The price after any coupon code divided by the total milligrams in a vial, used to compare vials of different sizes. Larger vials are almost always cheaper per milligram. Blends, capsules and solvents are compared by total price instead.
U-100 unit: A graduation on an insulin syringe where 100 units equal 1 millilitre, so one unit is 0.01 mL. Concentrations are converted into units so a volume can be read off the barrel.
Growth hormone secretagogue: A compound that acts on the ghrelin or growth-hormone-releasing-hormone receptor to stimulate release of growth hormone. Ipamorelin, CJC-1295 and MK-677 are described this way in the research literature.
Peptide bioregulator: A very short peptide, usually two to four amino acids, from the research tradition associated with Vladimir Khavinson in St Petersburg. Epithalon, Thymalin, Pinealon and Vilon are sold under this heading.
Peptide blend: Two or more peptides co-lyophilized in a single vial, sold as one product at a combined strength such as 10/10 mg. KLOW, GLOW and BPC-157 / TB-500 are blends; they are priced as a set rather than per milligram.
SARM: Selective androgen receptor modulator, a class of investigational non-steroidal compounds. They are supplied as capsules or solution rather than lyophilized powder and are compared by total price per unit.
Aggregate offer: The range of prices for one product across every vendor, from the lowest in-stock price to the highest. Each product page shows this range and links to every individual offer.