Hormonal Peptides

Also: Kisspeptin-10, Kisspeptin-54

Kisspeptin is the master switch that tells your brain to start reproduction. It is a family of peptides (the full length is kisspeptin-54, with shorter active fragments KP-14, KP-13, and KP-10) made from the KISS1 gene, and it acts as the upstream trigger for the entire reproductive hormone cascade. It is not an approved drug, but it has been tested in real human trials for fertility, hypothalamic amenorrhea, and male hypogonadism, with promising early results.

Also: Mitochondrial ORF of the 12S rRNA type-c

MOTS-c is a 16-amino-acid peptide your own mitochondria make, encoded inside the 12S rRNA region of mitochondrial DNA and discovered in 2015. It is studied as a metabolic regulator and a so-called exercise mimetic, because its levels rise when you work out and it improves insulin sensitivity in animals. The catch: the impressive results are almost entirely in mice, with no completed published human efficacy trials.

Also: Pitocin, Syntocinon

Oxytocin is a 9-amino-acid hormone made in the hypothalamus, famous as the chemistry behind labor contractions, breastfeeding, and social bonding. As an injectable drug it is FDA-approved to induce labor and control postpartum bleeding, but the intranasal 'love hormone' versions sold for trust, anxiety, and autism are experimental and the human results are genuinely mixed. The hype runs well ahead of the evidence.

Also: GnRH, LHRH

Gonadorelin is a synthetic copy of natural GnRH (gonadotropin-releasing hormone), a 10-amino-acid peptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) that tells the pituitary to release LH and FSH. It is FDA-approved for evaluating pituitary function and has historical use in inducing ovulation. In the peptide world it is mostly used off-label to keep the testes working during testosterone replacement, and the catch is that timing matters enormously: pulse it and you stimulate, give it continuously and you shut the system down.

Also: Lupron, Eligard

Leuprolide (brand name Lupron) is a synthetic GnRH agonist, a modified peptide about 20 times more potent than natural GnRH, and it is FDA-approved for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty. The clever part is counterintuitive: it works by overstimulating the GnRH system so hard that the pituitary shuts down sex hormone production. It is a real, long-established prescription drug, not a research peptide, and it carries meaningful side effects from the low-hormone state it creates.

Also: DDAVP, Stimate

Desmopressin (dDAVP) is a synthetic tweak of the natural hormone vasopressin, redesigned to keep the water-retaining effect while dropping most of the blood-pressure effect. It is a long-established FDA-approved drug used for central diabetes insipidus, bedwetting and nocturia, and certain bleeding disorders like von Willebrand disease and mild hemophilia A. This is settled medicine, not an experimental peptide, and its main real-world danger is straightforward: it can drop your blood sodium dangerously low if you drink too much fluid on it.

Also: Sandostatin, Octreotide LAR

Octreotide is a synthetic eight-amino-acid mimic of the natural hormone somatostatin, the body's main 'off switch' for hormone secretion. It shuts down excess growth hormone, so it is a frontline FDA-approved drug for acromegaly, and it also tames the flushing and diarrhea of hormone-secreting carcinoid and other neuroendocrine tumors. This is real, approved medicine with decades of clinical data behind it, sold as Sandostatin (injectable, since 1988), Sandostatin LAR (monthly depot), and Mycapssa (oral capsule, approved 2020).

Also: Somatuline, Somatuline Depot

Lanreotide is an eight-amino-acid somatostatin analog, a close cousin of octreotide, given as a long-acting deep-injection gel (Somatuline Depot/Autogel) usually once a month. It is FDA-approved for acromegaly and for gastroenteropancreatic neuroendocrine tumors, and it carries an approval for carcinoid syndrome. It is established prescription medicine, not an experimental compound.

Also: Signifor, Signifor LAR

Pasireotide (brand name Signifor) is a second-generation somatostatin analog, a cyclic six-amino-acid peptide engineered to hit more receptor subtypes than octreotide or lanreotide. Its standout use is Cushing's disease, where it was the first drug FDA-approved (2012) to directly target the pituitary tumor driving cortisol excess, and it is also approved for acromegaly that resists first-line analogs. The catch is real and well known: it raises blood sugar in most patients, so it is a powerful but high-maintenance option.

Also: Somavert

Pegvisomant (brand name Somavert) flips the usual acromegaly strategy on its head: instead of telling the tumor to make less growth hormone, it blocks growth hormone's receptor on target tissues directly. It is a PEGylated, genetically modified version of human growth hormone that acts as a receptor antagonist, FDA-approved in 2003 for acromegaly patients who do not respond well to surgery or other drugs. It is the single most effective option for normalizing IGF-1, which is why it is a key second-line therapy.

Also: Forteo, PTH 1-34

Teriparatide (brand name Forteo) is the first 34 amino acids of human parathyroid hormone, made by recombinant DNA, and it was the first drug approved that actually builds new bone rather than just slowing its loss. FDA-approved in 2002 for osteoporosis at high fracture risk, it is given as a once-daily self-injection. The counterintuitive trick is that the same hormone which strips calcium from bone when high around the clock instead grows bone when delivered in a short daily pulse.

Also: Tymlos, BA058

Abaloparatide (brand name Tymlos) is a synthetic 34-amino-acid analog of parathyroid hormone-related protein (PTHrP), and like teriparatide it is an anabolic osteoporosis drug that builds new bone. The FDA approved it in April 2017 for postmenopausal women at high fracture risk, and in December 2022 added men with osteoporosis at high fracture risk. It is the second drug in its class and was designed to lean harder on bone formation with less of the bone-breakdown and calcium-spike baggage.

Also: Regular Insulin, Humulin

Insulin is the body's main blood-sugar-lowering hormone, a 51-amino-acid protein made of two chains (a 21-residue A-chain and a 30-residue B-chain) held together by disulfide bonds. Secreted by the beta cells of the pancreas, it tells the liver, muscle, and fat to take up glucose and store energy. Discovered in 1921 and first given to a patient in January 1922, it remains one of the most consequential drugs in medicine and is the cornerstone of treatment for type 1 and many cases of type 2 diabetes.

Also: GlucaGen, Baqsimi

Glucagon is insulin's counterweight, a 29-amino-acid peptide hormone secreted by the alpha cells of the pancreas that raises blood sugar instead of lowering it. When glucose drops, glucagon tells the liver to break down stored glycogen and make new glucose, pushing blood sugar back up. Medically it is the emergency rescue treatment for severe hypoglycemia (the kind that knocks out a person with diabetes), available as injectable kits and a nasal-spray form, and it is also used in some diagnostic imaging to relax the gut.

Also: Miacalcin, Fortical

Calcitonin is a 32-amino-acid peptide hormone made by the parafollicular (C) cells of the thyroid gland, and it lowers blood calcium by putting the brakes on bone breakdown. The therapeutic version is usually salmon calcitonin, which is more potent and longer-lasting than the human form, sold as Miacalcin and similar products in injectable and nasal-spray forms. It is FDA-approved for Paget's disease of bone, hypercalcemia, and postmenopausal osteoporosis, though its osteoporosis role has shrunk dramatically over the years.

Also: Cortrosyn, ACTH 1-24

Cosyntropin is a synthetic fragment of the body's own stress hormone, ACTH, stripped down to the first 24 amino acids that do the actual work. Doctors do not use it to treat anything. They inject it to ask the adrenal glands a single question: can you make cortisol on demand? It is the backbone of the standard test for adrenal insufficiency.

Also: Integrilin

Eptifibatide is an FDA-approved intravenous antiplatelet drug, sold as Integrilin, and it has an oddly cool origin: it is a synthetic cyclic heptapeptide modeled on barbourin, a protein from the venom of the southeastern pygmy rattlesnake. It is used in hospitals during acute coronary syndromes and percutaneous coronary intervention (PCI, the stent procedure) to stop platelets from clumping and forming dangerous clots. This is a real, approved cardiac drug, not a wellness or research peptide.

Also: Angiomax, Angiox

Bivalirudin is an FDA-approved anticoagulant (brand name Angiomax) and a synthetic 20 amino acid peptide based on hirudin, the natural anticlotting molecule from medicinal leeches. It is given intravenously during PCI and in some acute coronary syndrome and heparin-induced-thrombocytopenia situations to prevent clots while keeping bleeding lower than older drugs. This is a hospital-grade prescription anticoagulant with a long clinical track record, approved by the FDA in 2000.

Also: FST, FS344

Follistatin is a naturally occurring protein in your body whose claim to fame is shutting down myostatin, the brake that limits how much muscle you can build. Block myostatin and muscle grows, which is why follistatin has been chased hard as a therapy for muscle-wasting diseases and, less responsibly, as a physique-enhancement target. Most of the serious work uses gene therapy that tells muscle to produce follistatin, not injectable follistatin peptide, and nothing here is FDA approved.

Also: ACVR2B-Fc, Myostatin Inhibitor

ACE-031 was an experimental muscle-building drug, technically a fusion protein that joins the activin receptor type IIB to the Fc portion of an antibody, designed to mop up myostatin and related growth-limiting signals from the bloodstream. It was developed by Acceleron Pharma and tested in boys with Duchenne muscular dystrophy with the goal of preserving muscle. It is not approved, and its development was stopped over safety concerns, so it exists today only as a discontinued investigational compound.

Also: Macrilen, AEZS-130

Macimorelin (brand name Macrilen) is an orally active ghrelin receptor agonist used as a diagnostic test, not a treatment. You drink a single dose, then doctors measure how much growth hormone the pituitary releases to diagnose adult growth hormone deficiency. It was FDA approved in December 2017 as the first oral diagnostic agent for that condition.

Also: Linzess, Constella

Linaclotide (brand name Linzess in the US, Constella in Europe) is a 14-amino-acid synthetic peptide and a guanylate cyclase-C agonist, FDA-approved in August 2012. It is a real prescription gut drug, taken once daily by mouth, for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation. It does two things at once: it gets sluggish bowels moving and it dials down the abdominal pain that comes with IBS.

Also: Trulance

Plecanatide (brand name Trulance) is a 16-amino-acid peptide and a guanylate cyclase-C agonist, FDA-approved in January 2017 for chronic idiopathic constipation and later for IBS-C. It is essentially a close cousin of linaclotide, designed to mimic the body's own gut hormone uroguanylin, and it is taken as a 3 mg tablet once a day. Think of it as a second-generation version of the same idea, engineered to be a touch more pH-selective in the gut.

Also: PTG-300, Rusfertide injection

Rusfertide is an injectable peptide that mimics hepcidin, the body's master hormone for controlling iron, and it is being developed to manage polycythemia vera (PV), a blood cancer that makes too many red blood cells. By limiting iron availability, it throttles red blood cell production and reduces the need for repeated blood draws (phlebotomy). It is a late-stage investigational drug, not a research-only or gray-market peptide: it cleared a positive phase 3 trial and is under FDA priority review.