Peptide classes

Calcitonin is a 32-amino-acid peptide hormone with a fascinating role in bone biology. Here's how the chemistry and regulation actually work.

Collagen peptides are a widely consumed food supplement in Australia. Here's what the chemistry and regulation actually say — without the marketing noise.

GLP-1 receptor agonists are a class of peptide-based medicines with a distinct mechanism and a heavily regulated place in Australian prescribing.

GnRH analogues are among the most pharmacologically elegant peptide classes in clinical medicine. Here's how their chemistry and regulation actually work.

Growth hormone doesn't act alone. Here's how the somatotropic axis works — the chemistry, the regulation, and what Australian law says about GH-related compounds.

Growth-hormone secretagogues have a layered regulatory history in Australia. Here's what the scheduling, chemistry and enforcement picture actually looks like.

Insulin was the first peptide medicine to enter clinical use. Here's the chemistry, history, and regulatory story behind the molecule that changed everything.

Melanocortin peptides: what they are, how they work at the receptor level, their history, and what Australian law says about their supply.

Natriuretic peptides are endogenous cardiac hormones with a well-characterised signalling biology. Here's what the science actually says about how they work.

Oxytocin and vasopressin are nine-amino-acid neuropeptides with overlapping structures but distinct receptor pharmacology. Here's what the science actually says.

Many peptide-based compounds are administered by injection rather than swallowed. The reason lies in basic biochemistry and how the digestive system works.

Amino acids are the molecular building blocks that join together to form peptides and proteins.

Angiotensin II is an endogenous octapeptide hormone central to the renin–angiotensin–aldosterone system (RAAS), where it regulates blood pressure, fluid balance, and electrolyte homeostasis through vasoconstriction and aldosterone release.

Atrial Natriuretic Peptide (ANP) is a 28-amino-acid endogenous peptide hormone secreted primarily by cardiac atrial cells in response to increased atrial wall stretch, where it acts on renal and vascular targets to promote sodium excretion and vasodilation.

Bradykinin is an endogenous nine-amino-acid peptide belonging to the kinin family, generated primarily through the kallikrein–kinin system and involved in vasodilation, vascular permeability, pain signalling, and inflammatory responses.

Carbetocin is a synthetic, long-acting analogue of the endogenous nonapeptide oxytocin, developed to reduce postpartum haemorrhage by stimulating sustained uterine contraction after childbirth or caesarean section.

Desmopressin is a synthetic analogue of the endogenous nonapeptide arginine vasopressin (AVP), modified to enhance antidiuretic potency and reduce vasopressor activity.

Enfuvirtide is a synthetic 36-amino-acid peptide that inhibits HIV-1 entry into host cells by blocking fusion of the viral and cell membranes.

Erythropoietin (EPO) is an endogenous glycoprotein hormone produced primarily by the kidneys that regulates red blood cell production by stimulating erythroid progenitor cell differentiation in bone marrow.

Filgrastim is a recombinant form of human granulocyte colony-stimulating factor (G-CSF), a glycoprotein that stimulates the bone marrow to produce and release neutrophils into the bloodstream.

Ghrelin is an endogenous 28-amino-acid peptide hormone, primarily secreted by specialised cells of the gastric fundus, that acts as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a) and plays a central role in appetite regulation, energy homeostasis, and pulsatile growth hormone release.

Glatiramer acetate is a synthetic polypeptide mixture composed of four amino acids — glutamic acid, lysine, alanine, and tyrosine — that mimics structural properties of myelin basic protein and is classified as a prescription-only medicine in Australia under the Therapeutic Goods Administration (TGA) regulatory framework.

A GLP-1 receptor agonist is a class of peptide-based compound that activates the receptor for glucagon-like peptide-1.

Glucagon is a 29-amino-acid peptide hormone secreted by the alpha cells of the pancreatic islets of Langerhans that acts as the primary counter-regulatory hormone to insulin, stimulating hepatic glucose production to raise blood glucose concentrations.

Goserelin is a synthetic decapeptide analogue of gonadotropin-releasing hormone (GnRH) that acts on the pituitary gland to suppress the release of luteinising hormone (LH) and follicle-stimulating hormone (FSH), resulting in a profound reduction in gonadal sex hormone production.

Icatibant is a synthetic, selective bradykinin B2 receptor antagonist — a ten-amino-acid peptidomimetic used in the acute treatment of hereditary angioedema (HAE) attacks in adults.

Insulin-like Growth Factor 1 (IGF-1) is a 70-amino-acid endogenous peptide hormone, structurally homologous to insulin, that mediates many of the growth-promoting effects of growth hormone (GH) and acts on IGF-1 receptors distributed throughout skeletal muscle, bone, liver, and the central nervous system.

Leptin is an endogenous peptide hormone, encoded by the LEP gene and produced predominantly by white adipose tissue, that signals energy-reserve status to the hypothalamus and other brain regions involved in appetite and metabolic regulation.

Linaclotide is a synthetic 14-amino-acid peptide agonist of guanylate cyclase-C (GC-C) receptors in the intestinal epithelium, approved in multiple jurisdictions as a prescription medicine for gastrointestinal conditions and listed on the Australian Register of Therapeutic Goods (ARTG) as a Schedule 4 (prescription-only) product under the Therapeutic Goods Administration (TGA) framework.

Liraglutide is a synthetic analogue of human glucagon-like peptide-1 (GLP-1), a 34-amino-acid acylated peptide that acts as an agonist at GLP-1 receptors and is approved in Australia for specific medical indications under prescription.

Octreotide is a synthetic octapeptide analogue of the endogenous hormone somatostatin, developed to replicate somatostatin's inhibitory actions on growth hormone secretion while offering a substantially longer plasma half-life.

Parathyroid Hormone (PTH) is an endogenous 84-amino-acid peptide secreted by the parathyroid glands that plays a central role in calcium and phosphate homeostasis in humans and other vertebrates.

A peptide is a short chain of amino acids linked by peptide bonds, smaller than a full protein.

A peptide bond is the chemical linkage that joins two amino acids together within a peptide or protein.

Sermorelin is a synthetic 29-amino-acid peptide analogue of endogenous growth hormone-releasing hormone (GHRH) that acts on the pituitary gland to stimulate the secretion of growth hormone.

Somatostatin (somatotropin-release inhibiting factor) is an endogenous cyclic peptide hormone produced primarily in the hypothalamus and pancreatic delta cells that inhibits the secretion of growth hormone, insulin, glucagon, and several gastrointestinal hormones.

Substance P is an endogenous eleven-amino-acid neuropeptide of the tachykinin family, produced throughout the central and peripheral nervous systems, where it acts primarily as a neurotransmitter and neuromodulator via neurokinin 1 (NK1) receptors.

Teriparatide is a synthetic 34-amino-acid peptide corresponding to the biologically active N-terminal fragment of human parathyroid hormone (PTH 1–34), classified as a prescription-only medicine in Australia and used in an approved clinical context.

Thymosin Beta-4 is an endogenous 43-amino-acid peptide found in virtually all human tissues, studied for its roles in actin sequestration, cellular signalling, and tissue homeostasis, but not approved as a therapeutic drug in Australia.

Vasopressin (antidiuretic hormone, ADH) is an endogenous nine-amino-acid cyclic peptide synthesised in the hypothalamus that regulates water reabsorption in the renal collecting ducts and mediates vasoconstriction at higher concentrations.