Plain-English definitions of the peptide and DNA terms you’ll meet across PeptideXR — each linked to the full referenced article where relevant.
- Agonist
- A molecule that binds a receptor and activates it, mimicking the body's natural signal.
- Amino acid
- The building blocks of peptides and proteins; their sequence defines a peptide's function.
- AOD9604
- A modified fragment of HGH studied for fat metabolism. → full profile
- Ara-290 (Cibinetide)
- An EPO-derived peptide studied for tissue protection and neuropathic pain. → full profile
- Bacteriostatic water (BAC water)
- Sterile water with 0.9% benzyl alcohol, used to reconstitute peptides for multi-dose use.
- Bioavailability
- The fraction of a dose that reaches circulation intact; most peptides have poor oral bioavailability and are injected.
- BPC-157
- A synthetic pentadecapeptide widely studied in rodents for tendon, gut and tissue repair. → full profile
- Cagrilintide
- A long-acting amylin analog studied for appetite control, often paired with semaglutide (CagriSema). → full profile
- Certificate of Analysis (COA)
- A lab document reporting purity, identity and contamination results — ideally independently verifiable.
- CJC-1295
- A GHRH analog that raises growth hormone and IGF-1; with or without DAC for different half-lives. → full profile
- Endotoxin
- Bacterial lipopolysaccharide that can cause fever and inflammation; measured by the LAL assay.
- Epitalon
- A synthetic tetrapeptide studied for telomere and circadian effects. → full profile
- GHK-Cu
- A copper-binding tripeptide associated with skin remodeling, collagen and wound healing. → full profile
- GHRP-2
- A growth-hormone-releasing peptide that stimulates GH secretion. → full profile
- GHRP-6
- A growth-hormone-releasing peptide that also strongly stimulates appetite. → full profile
- GIP
- Glucose-dependent insulinotropic polypeptide, a second incretin hormone; tirzepatide is a dual GLP-1/GIP agonist.
- GLP-1 (glucagon-like peptide-1)
- An incretin hormone that boosts insulin, suppresses glucagon, slows gastric emptying and curbs appetite — the target of semaglutide and tirzepatide.
- Half-life
- The time for half a dose to clear the body; it sets dosing frequency (a long half-life allows weekly dosing).
- Hexarelin
- A potent growth-hormone secretagogue. → full profile
- HPLC
- High-Performance Liquid Chromatography; the standard method for measuring peptide purity.
- Ipamorelin
- A selective growth-hormone secretagogue that triggers GH release with minimal side effects. → full profile
- Lyophilized
- Freeze-dried; the stable powder form in which most peptides are shipped and stored.
- Mass spectrometry
- Confirms a molecule's identity by measuring its mass-to-charge ratio.
- Mazdutide
- A dual GLP-1/glucagon agonist in development for obesity and metabolic disease. → full profile
- Melanotan II
- A melanocortin agonist studied for skin pigmentation (tanning). → full profile
- MGF (Mechano Growth Factor)
- An IGF-1 splice variant studied for muscle repair. → full profile
- MOTS-c
- A mitochondrial-derived peptide studied as an exercise-mimetic and metabolic regulator. → full profile
- NAD+
- A coenzyme central to cellular energy and a focus of longevity research. → full profile
- Peptide
- A short chain of amino acids (typically 2–50) that acts as a signaling molecule; smaller than a protein.
- Pharmacokinetics (PK)
- How the body absorbs, distributes, metabolizes and eliminates a compound over time.
- PT-141 (Bremelanotide)
- A melanocortin agonist studied for sexual dysfunction. → full profile
- Receptor
- A protein a peptide binds to, triggering a biological response inside the cell.
- Reconstitution
- Dissolving a lyophilized peptide powder in bacteriostatic or sterile water before use.
- Research use only (RUO)
- A designation meaning a compound is sold for laboratory research, not approved for human use.
- Retatrutide
- An investigational triple GLP-1/GIP/glucagon agonist showing the steepest weight-loss curve to date. → full profile
- Secretagogue
- A compound that prompts the body to secrete a hormone — e.g. growth-hormone secretagogues trigger natural GH release.
- Selank
- An anxiolytic peptide derived from tuftsin, studied for stress and anxiety. → full profile
- Semaglutide
- A GLP-1 receptor agonist for type-2 diabetes and weight loss (Ozempic, Wegovy). → full profile
- Semax
- A neuropeptide studied for cognition and neuroprotection. → full profile
- Stack
- Combining multiple peptides in a protocol intended to produce complementary effects.
- Subcutaneous (SubQ)
- Injection into the fat layer beneath the skin — the most common route for research peptides.
- TB-500
- A synthetic fragment of Thymosin Beta-4 studied for tissue repair and flexibility. → full profile
- Tesamorelin
- A GHRH analog approved to reduce visceral adipose tissue. → full profile
- Thymosin Alpha-1
- An immune-modulating peptide used clinically as an adjuvant in some regions. → full profile
- Tirzepatide
- A dual GLP-1/GIP agonist with strong weight-loss and glycemic effects (Mounjaro, Zepbound). → full profile