Mechanisms of Action
How Peptides Work
Peptides produce their clinical effects by binding specific receptors and modulating intracellular signaling. Each mechanism below groups the compounds that share a common pathway — from GLP-1 receptor agonism (the class behind semaglutide and tirzepatide) to growth hormone releasing hormone receptor stimulation and beyond.
GHRH Receptor Agonism
Stimulation of the pituitary GHRH receptor to trigger pulsatile, physiological growth hormone release.
Ghrelin Receptor Agonism
Activation of the growth hormone secretagogue receptor (GHSR-1a) — the ghrelin receptor — to drive GH release through a second pathway.
Melanocortin Receptor Agonism
Activation of central melanocortin receptors (MC3R/MC4R) modulating sexual function, appetite, and skin pigmentation.
Actin Sequestration & Cell Migration
Modulation of cytoskeletal actin dynamics to enhance cell migration, angiogenesis, and tissue regeneration.
Angiogenesis & VEGF Modulation
Promotion of new blood vessel formation and upregulation of VEGF signaling at injury sites.
Copper-Dependent Gene Modulation
Copper-binding tripeptide that modulates expression of wound healing, collagen, and antioxidant genes.
Dendritic Cell & T-Cell Activation
Activation of dendritic cells and T-lymphocytes to restore adaptive immune competence.
Dual GIP / GLP-1 Agonism
Simultaneous activation of both the GIP and GLP-1 receptors — the "twincretin" class — for amplified metabolic effects.
GLP-1 Receptor Agonism
Activation of the glucagon-like peptide-1 receptor to slow gastric emptying, enhance insulin secretion, and reduce appetite.
Lipolytic GH Fragment Activity
Growth hormone C-terminal fragment that selectively promotes lipolysis without the anabolic effects of full-length GH.
Melanocortin & BDNF Signaling
ACTH fragment analogs that modulate melanocortin pathways and upregulate brain-derived neurotrophic factor.
Mitochondrial-Derived AMPK Activation
Mitochondrial-derived peptide that activates AMPK, improving glucose homeostasis and metabolic flexibility.
NAD⁺ / Sirtuin & PARP Cofactor
Supplementation of the NAD⁺ pool to support sirtuin, PARP, and mitochondrial metabolism.
Telomerase Activation
Upregulation of telomerase to maintain telomere length and support cellular longevity.
Triple GIP / GLP-1 / Glucagon Agonism
Simultaneous activation of GIP, GLP-1, and glucagon receptors for metabolic reprogramming and maximal weight loss.
Tuftsin Analog Immune-Neuro Modulation
Tuftsin-derived peptide that modulates immune function, anxiety, and cognition.
Mechanism Comparisons
Head-to-head comparisons of peptide mechanisms — receptor biology, therapeutic areas, and evidence depth across pathway classes.
GLP-1 Receptor Agonism vs Dual GIP / GLP-1 Agonism
Compare pathway, evidence, and compounds
GLP-1 Receptor Agonism vs Triple GIP / GLP-1 / Glucagon Agonism
Compare pathway, evidence, and compounds
Dual GIP / GLP-1 Agonism vs Triple GIP / GLP-1 / Glucagon Agonism
Compare pathway, evidence, and compounds
GHRH Receptor Agonism vs Ghrelin Receptor Agonism
Compare pathway, evidence, and compounds
GHRH Receptor Agonism vs Lipolytic GH Fragment Activity
Compare pathway, evidence, and compounds
Ghrelin Receptor Agonism vs Lipolytic GH Fragment Activity
Compare pathway, evidence, and compounds
Angiogenesis & VEGF Modulation vs Actin Sequestration & Cell Migration
Compare pathway, evidence, and compounds
Angiogenesis & VEGF Modulation vs Copper-Dependent Gene Modulation
Compare pathway, evidence, and compounds
Actin Sequestration & Cell Migration vs Copper-Dependent Gene Modulation
Compare pathway, evidence, and compounds
Melanocortin Receptor Agonism vs Melanocortin & BDNF Signaling
Compare pathway, evidence, and compounds
Telomerase Activation vs NAD⁺ / Sirtuin & PARP Cofactor
Compare pathway, evidence, and compounds
NAD⁺ / Sirtuin & PARP Cofactor vs Mitochondrial-Derived AMPK Activation
Compare pathway, evidence, and compounds
Telomerase Activation vs Mitochondrial-Derived AMPK Activation
Compare pathway, evidence, and compounds
Tuftsin Analog Immune-Neuro Modulation vs Dendritic Cell & T-Cell Activation
Compare pathway, evidence, and compounds
GLP-1 Receptor Agonism vs Lipolytic GH Fragment Activity
Compare pathway, evidence, and compounds
GLP-1 Receptor Agonism vs Mitochondrial-Derived AMPK Activation
Compare pathway, evidence, and compounds
Why Mechanism Matters
A peptide's mechanism of action determines not only what it does, but what it won't do. GLP-1 agonists reduce appetite and improve glycemic control because they activate a receptor expressed in the pancreas and hypothalamus. GHRH analogs avoid the supraphysiologic effects of exogenous growth hormone because they preserve hypothalamic negative feedback.
Understanding mechanism is also the fastest way to predict side effects, interactions, and stacking logic. Peptides that share a mechanism usually share a side-effect profile — all GLP-1 agonists cause some degree of GI upset; all melanocortin agonists can cause facial flushing. Compounds with complementary mechanisms (like GHRH + ghrelin agonists) often produce additive effects in research.