Oxytocin

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.

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.

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.

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.

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).

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.