Peptide Glossary

The building blocks of peptides and proteins. There are 20 standard amino acids that combine in different sequences to form every peptide.

Sterile water containing 0.9% benzyl alcohol, used to reconstitute lyophilized peptides. The preservative prevents bacterial growth, allowing multi-use vials.

The proportion of a compound that enters systemic circulation and produces an active effect. Subcutaneous injection typically has higher bioavailability than oral administration for peptides.

Body Protection Compound. A pentadecapeptide (15 amino acids) derived from human gastric juice with broad tissue-protective properties.

Chemical Abstracts Service registry number. A unique numerical identifier for chemical substances used to verify compound identity.

A document from a testing laboratory reporting the identity, purity, and composition of a compound. Third-party COAs from named labs are the gold standard for verifying peptide quality.

A temperature-controlled supply chain that keeps peptides within specified ranges (typically 2-8°C) during shipping and storage to prevent degradation.

A pharmacy that creates customized medications, including peptide formulations, tailored to individual prescriptions.

A unit of molecular mass equal to one-twelfth the mass of a carbon-12 atom. Peptide molecular weights are typically expressed in Daltons or kilodaltons (kDa).

Gradually increasing a compound's dose from a low starting point to find the optimal effective dose while minimizing side effects.

A test (typically LAL or Limulus Amebocyte Lysate) that detects bacterial endotoxins in injectable products. A critical quality control step for peptides.

An FDA classification for compounded bulk drug substances under evaluation. The substance may be included on the FDA's bulk drug substances list for compounding.

The process of freezing and then thawing a reconstituted peptide. Repeated cycles can denature the peptide, reducing potency. Should be minimized.

Human growth hormone (somatropin), a 191-amino acid protein produced by the pituitary gland. Several peptides (GHRP, GHRH analogs) stimulate its release.

Growth Hormone-Releasing Hormone. A hypothalamic peptide that stimulates pituitary GH secretion. Analogs like CJC-1295 and Sermorelin mimic its action.

Growth Hormone-Releasing Peptide. A class of synthetic peptides (Ipamorelin, GHRP-2, GHRP-6, Hexarelin) that stimulate GH release through the ghrelin receptor.

Glucagon-Like Peptide-1. An incretin hormone that regulates blood sugar and appetite. Semaglutide and Tirzepatide are GLP-1 receptor agonists.

The time required for a compound's concentration to decrease by half. Determines dosing frequency — shorter half-lives require more frequent administration.

Laboratory analysis for toxic metals (arsenic, cadmium, lead, mercury) in peptide products. Required for quality assurance of injectable compounds.

High-Performance Liquid Chromatography. The standard analytical technique for determining peptide purity. Results are reported as a percentage (e.g., >99% pure).

A small-gauge syringe (typically 29-31G) designed for subcutaneous injection. Commonly used for peptide administration due to the small injection volumes.

An injection route delivering a compound into muscle tissue. Used for some peptides requiring slower absorption than subcutaneous injection.

Administration directly into a vein for immediate systemic availability. Used for some clinical peptides like NAD+ and glutathione.

International standard for testing and calibration laboratories. Labs accredited to ISO 17025 meet rigorous quality and competence requirements.

A widely used independent analytical laboratory that provides third-party peptide testing. Results are publicly verifiable on their database.

Freeze-drying. The process of removing water from a peptide solution to create a stable powder (lyophilized cake). Most peptides ship in lyophilized form.

An analytical technique that measures the mass-to-charge ratio of molecules. Used alongside HPLC to confirm peptide identity and detect impurities.

The sum of atomic weights of all atoms in a molecule, measured in Daltons. Important for calculating molar concentrations and comparing peptides.

A chain of 2-50 amino acids linked by peptide bonds. Larger chains (50+) are generally classified as proteins. Most research compounds are peptides.

The covalent bond formed between the carboxyl group of one amino acid and the amino group of the next. The backbone of all peptides.

The attachment of polyethylene glycol (PEG) chains to a peptide. Increases half-life by reducing renal clearance and enzymatic degradation.

The study of how the body absorbs, distributes, metabolizes, and excretes a compound. Determines dosing schedules and bioavailability.

The normalized cost metric used to compare peptide prices across vendors selling different package sizes. Calculated as total price divided by total milligrams.

The percentage of the desired compound in a sample, typically measured by HPLC. Research-grade peptides should be >98% pure; pharmaceutical grade is >99%.

The process of dissolving lyophilized peptide powder in bacteriostatic water or sterile saline to create an injectable solution.

A compound sold for laboratory research purposes only, not for human consumption. Most peptides are sold under this designation.

A substance that promotes secretion. Growth hormone secretagogues (e.g., Ipamorelin, CJC-1295) stimulate the body's own GH production.

A compound that selectively eliminates senescent (aged, non-dividing) cells. FOXO4-DRI is an example of a senolytic peptide.

The specific order of amino acids in a peptide chain, written from N-terminus to C-terminus. Determines the peptide's structure and function.

The reference dose size used to normalize prices across vendors. For example, if the standard unit for BPC-157 is 5mg, all prices are compared per 5mg.

Laboratory testing to confirm the absence of viable microorganisms in a peptide product. Essential for injectable compounds.

An injection route delivering a compound into the fatty tissue layer beneath the skin. The most common administration route for research peptides.

An advanced mass spectrometry technique that fragments molecules for more precise identification. Used for confirming peptide sequences.

Laboratory analysis performed by an independent lab (not the vendor). Provides unbiased verification of purity, identity, and sterility.

The concentration of a substance in a solution. For peptides, this typically refers to the amount of active compound per milliliter after reconstitution.

A small sealed container for peptide storage. Typically 2-5mL glass vials with rubber stoppers for multi-use access with a syringe needle.

World Anti-Doping Agency. Many peptides including growth hormone secretagogues and SARMs are on the WADA Prohibited List.