Peptide Research Glossary
Definitions for common terms used in peptide research, dosing, and reconstitution. Browse alphabetically or search by topic.
A
Acetic acid (0.6%)
Used to reconstitute IGF-1 LR3 and some other peptides. The acidic environment stabilises the peptide structure. Must be diluted with bacteriostatic water before injection.
Acromegaly
Condition caused by excess growth hormone after growth plate closure. Relevant as an upper-limit reference for GH safety.
Amide bond / Amidation
C-terminal modification in some peptides (e.g CJC-1295) that improves stability against proteolysis.
Angiogenesis
Formation of new blood vessels. BPC-157 promotes angiogenesis via VEGF modulation — key part of its healing mechanism.
B
BAC water (Bacteriostatic water)
Sterile water containing 0.9% benzyl alcohol, which inhibits bacterial growth. Allows multiple draws from one vial over several weeks. Standard reconstitution solvent for most research peptides.
BDNF (Brain-Derived Neurotrophic Factor)
Protein supporting neuron survival and growth. Semax increases BDNF expression — considered part of its cognitive mechanism.
Bioavailability (subcutaneous)
Absorption of a peptide injected subcutaneously. Most research peptides have SC bioavailability of 60–90%, depending on molecular weight.
BPC-157
Body Protection Compound-157. Pentadecapeptide derived from a gastric protein. No human clinical trials — all evidence from rodent models.
C
cAMP (Cyclic AMP)
Intracellular signalling molecule. GHRH receptor activation triggers cAMP production, stimulating GH synthesis and release.
CJC-1295
Modified GHRH analogue. "No DAC" version has ~30-minute half-life; "with DAC" (Drug Affinity Complex) extends half-life to 7–10 days by binding to albumin.
Concentration (mcg/ml or mg/ml)
The amount of peptide dissolved per millilitre of solvent. Calculated as: Vial mass ÷ Reconstitution volume.
D
DAC (Drug Affinity Complex)
A lysine-maleimide modification on CJC-1295 that covalently binds to circulating albumin, dramatically extending half-life from ~30 min to 7–10 days.
E
Epithalon
Tetrapeptide (Ala-Glu-Asp-Gly) developed by Vladimir Khavinson. Claimed to regulate telomerase activity. Fixed 10 mg/day × 10-day cycles based on Russian clinical protocols.
F
Frequency (injection)
How often a peptide is administered. Expressed as injections per day or per week. Determines total vial consumption and days supply.
Freeze-drying (lyophilization)
Process that removes water from peptides under vacuum to create a stable powder (lyophilisate). Allows long-term storage at room temperature before reconstitution.
G
GH (Growth Hormone / Somatotropin)
Protein hormone released by the pituitary. Stimulates IGF-1 production. Declines ~14% per decade after age 30.
GHRH (Growth Hormone-Releasing Hormone)
Hypothalamic peptide that stimulates GH synthesis and release from the pituitary. CJC-1295 and Sermorelin are GHRH analogues.
GHRP (Growth Hormone-Releasing Peptide)
Class of synthetic peptides (Ipamorelin, GHRP-2, GHRP-6) that trigger GH release via ghrelin receptor (GHSR) activation. Mechanism independent of GHRH.
GIP (Glucose-dependent Insulinotropic Polypeptide)
Incretin hormone. Tirzepatide is a dual GIP+GLP-1 agonist — the GIP component contributes to its superior weight loss vs GLP-1 monotherapy.
GLP-1 (Glucagon-Like Peptide-1)
Incretin hormone that stimulates insulin release, suppresses glucagon, and delays gastric emptying. Semaglutide and Tirzepatide are GLP-1 agonists.
H
Half-life
Time for plasma concentration to fall by 50%. Short-acting peptides (Ipamorelin: ~2h) require multiple daily injections. Long-acting (CJC-1295 with DAC: 7–10 days) require weekly injection.
HGH
Human Growth Hormone. Identical to endogenously produced GH. Adult dosing per Endocrine Society: start 1 IU/day, titrate by IGF-I response. Weight-based dosing is NOT recommended for adults.
I
IGF-1 (Insulin-Like Growth Factor 1)
Primary downstream mediator of GH action, produced mainly in the liver. Blood IGF-1 is the standard marker used to titrate GH/HGH doses.
IGF-1 LR3
Long R3 IGF-1. Modified IGF-1 with reduced IGFBP binding — ~3× longer half-life (~20h vs ~6h). Reconstituted in 0.6% acetic acid.
Ipamorelin
Selective GHRP. Stimulates GH release without raising cortisol or prolactin — considered the cleanest GHRP. Clinical trials: 1–3 mcg/kg SC.
Insulin syringe units
Standard 1 ml insulin syringe = 100 units. Dose in units = volume (ml) × 100.
L
Lyophilisate
The dry powder produced by lyophilization (freeze-drying). What arrives in the peptide vial before reconstitution.
M
Melanotan II
Cyclic analogue of α-MSH. Activates MC1R (skin pigmentation) and MC4R (libido, erectile function). Weight-based dosing ~0.01 mg/kg. No regulatory approval.
N
NAD+ (Nicotinamide Adenine Dinucleotide)
Coenzyme central to cellular energy metabolism and DNA repair. Levels decline ~50% between ages 40–60. Injectable protocols: 100–1,000 mg/session fixed.
P
Peptide
Short chain of amino acids (2–50) linked by peptide bonds. Most research peptides are 5–30 amino acids. Larger chains are proteins (HGH = 191 amino acids).
Proteolysis
Enzymatic degradation of peptides by proteases in the body. Most peptides have very short half-lives due to rapid proteolytic breakdown. Chemical modifications (amidation, PEGylation, DAC) extend stability.
R
Reconstitution
Process of dissolving a lyophilized peptide powder in a liquid (usually bacteriostatic water) to create an injectable solution.
S
SC (Subcutaneous injection)
Injection into the fat layer beneath the skin. Standard route for most research peptides. Common sites: abdomen, outer thigh, upper arm.
Semaglutide
GLP-1 agonist. STEP trial: ~15% body weight loss over 68 weeks at 2.4 mg/week. Fixed escalation protocol regardless of body weight.
Sermorelin
GHRH analogue. Adult dosing: 200–500 mcg fixed (NOT weight-based). Pediatric dosing (30 mcg/kg) is not applicable to adult research.
T
TB-500
Synthetic fragment of Thymosin Beta-4 (Tβ4). Promotes actin polymerization, cell migration, and anti-inflammatory signalling. No human clinical trials — animal model only.
Tesamorelin
GHRH analogue, FDA-approved for HIV-associated lipodystrophy at 2 mg/day fixed. Only GH peptide with confirmed human clinical indication.
Thymosin Alpha-1
Immune-modulating peptide. 1.6 mg standard unit; FDA Orphan Drug designation. Fixed dose, not weight-dependent.
Tirzepatide
Dual GIP+GLP-1 agonist. SURMOUNT-1 trial: ~20% body weight loss over 72 weeks. Fixed escalation 2.5→15 mg/week regardless of body weight.
V
Vial (lyophilized)
Glass sealed container with lyophilized peptide powder. Common sizes: 1 mg, 2 mg, 5 mg, 10 mg. Typically stored at room temperature or refrigerated before reconstitution.
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