The Peptide Glossary — Clear Definitions from a Licensed RN

FDA-approved for type 2 diabetes (marketed as Ozempic) and chronic weight management (marketed as Wegovy). Mimics the naturally occurring GLP-1 hormone to regulate appetite and blood sugar. Works by stimulating insulin secretion, suppressing glucagon, and slowing gastric emptying. One of the most extensively studied peptide medications available.

FDA-approved for type 2 diabetes (marketed as Mounjaro) and chronic weight management (marketed as Zepbound). Uniquely targets both the GIP and GLP-1 receptor pathways simultaneously — the first dual incretin agonist approved for clinical use. Studies have demonstrated significant effects on blood sugar regulation and body weight.

A naturally occurring incretin hormone produced in the gut after eating. Stimulates insulin secretion, suppresses glucagon, and slows gastric emptying to regulate blood sugar and appetite. Semaglutide and liraglutide are synthetic analogs of this hormone with extended half-lives for therapeutic use.

A naturally occurring incretin hormone that works alongside GLP-1 to regulate insulin secretion after meals. Targets GIP receptors on pancreatic beta cells to amplify insulin response. Tirzepatide is the first approved medication to target this pathway in combination with GLP-1.

A coenzyme present in all living cells, essential for cellular energy production (ATP synthesis), DNA repair, and sirtuin activation. NAD+ levels decline significantly with age — by age 50, levels may be roughly half of what they were at age 20. Included here as a key longevity-related molecule despite not being a peptide. Research has explored various strategies for maintaining NAD+ levels during aging.

A family of proteins (enzymes) that regulate cellular health, metabolism, and stress responses. Require NAD+ as a co-substrate — which is why NAD+ levels directly affect sirtuin activity. Research has explored their roles in longevity, DNA repair, inflammation regulation, and metabolic function. SIRT1 is the most studied member of this family.

The rate-limiting enzyme in the NAD+ salvage pathway — the primary way the body recycles and maintains NAD+ levels. Converts nicotinamide (NAM) to nicotinamide mononucleotide (NMN), a direct precursor to NAD+. Research has explored its role in maintaining NAD+ levels during aging and its potential as a target for longevity interventions.

The chemical bond that links amino acids together to form peptides and proteins. Formed between the carboxyl group (–COOH) of one amino acid and the amino group (–NH₂) of another, releasing a water molecule in the process. This bond is the fundamental building block of every peptide — from a tripeptide like GHK-Cu to large proteins with thousands of amino acids.

The freeze-drying process used to stabilize peptides for storage and transport. Removes water while preserving the peptide's molecular structure. This is a standard laboratory technique that extends the shelf life of research compounds significantly.

The laboratory process of dissolving lyophilized peptide powder in a sterile diluent — typically bacteriostatic water or sterile water for injection. The choice of diluent and the volume used affects the final concentration of the reconstituted peptide. This is a standard laboratory preparation step described in research literature.

Derived from a protective protein found in human gastric juice. Preclinical research has explored its potential role in supporting tissue recovery across tendons, ligaments, muscle, bone, and the gastrointestinal tract. Discovered by Croatian researchers in the 1990s and studied in over 100 preclinical models.

A synthetic fragment of Thymosin Beta-4 involved in actin regulation and cell migration. Preclinical research has explored its potential for systemic tissue recovery, including tendons, ligaments, and muscle. Often discussed alongside BPC-157 as part of the "Wolverine Stack."

A naturally occurring tripeptide (glycine-histidine-lysine) with high affinity for copper ions. Research has explored roles in skin remodeling, wound repair, and collagen synthesis. First identified in human plasma in the 1970s; its levels decline significantly with age.

Encoded in mitochondrial DNA rather than nuclear DNA — one of the few known mitochondrial-derived peptides. Research has explored its effects on metabolic regulation, insulin sensitivity, and exercise capacity. It functions as a signaling molecule that communicates between mitochondria and the nucleus.

A pentapeptide that stimulates the ghrelin receptor (growth hormone secretagogue receptor) to trigger growth hormone release from the pituitary gland. Research has explored its effects on body composition and muscle tissue. Considered one of the more selective GH secretagogues — it stimulates GH release without significantly affecting cortisol or prolactin.

A synthetic analog of growth hormone-releasing hormone (GHRH) with an extended half-life compared to natural GHRH. Often researched alongside Ipamorelin — the combination targets both sides of the growth hormone release pathway. CJC-1295 with DAC (Drug Affinity Complex) has a half-life of approximately 8 days.

A modified fragment of the C-terminus of human growth hormone (amino acids 177-191). Research has explored its effects on fat metabolism — specifically whether it can stimulate lipolysis (fat breakdown) without the growth-related effects of full-length hGH. Developed in the late 1990s by an Australian biotech company.

A naturally occurring protein found in most human tissues. Plays a central role in actin polymerization (building the cell's internal scaffolding) and cell migration. TB-500 is a synthetic fragment of this protein. Thymosin Beta-4 is one of the most abundant peptides in the human body and is involved in wound repair processes.