Octreotide is a synthetic octapeptide that mimics somatostatin, the natural hormone that tells the body to slow down the release of growth hormone and several gut hormones. It carries a long list of code names from its development years, including SMS 201-995 and SMS-995, and the CAS number 83150-76-9. The FDA approved it in 1988, sold by Novartis as Sandostatin. A monthly long-acting depot, Sandostatin LAR, followed in 1998, and an oral delayed-release version (Mycapssa) was approved in 2020 for maintenance treatment of acromegaly.
This is a real prescription drug, not a research-only compound. Nothing below is medical or dosing advice.
What it is and how it works
Natural somatostatin has a half-life measured in a few minutes, which makes it impractical as a therapy. Octreotide was engineered to last far longer: its plasma elimination half-life runs roughly 1.7 to 1.9 hours, and its effects can persist up to about 12 hours depending on the condition being treated, per the Sandostatin FDA label.
It works by binding somatostatin receptors, with the strongest affinity for the SSTR2 and SSTR5 subtypes. These are G-protein-coupled receptors. Activating them suppresses the release of growth hormone and thyroid-stimulating hormone from the pituitary, and dials down a range of gut and pancreatic hormones, including insulin, glucagon, gastrin, vasoactive intestinal peptide (VIP), secretin, and motilin. It also inhibits serotonin release and reduces splanchnic (gut) blood flow. According to the label, octreotide is actually a more potent inhibitor of growth hormone, glucagon, and insulin than somatostatin itself.
What the research and approvals show
The acromegaly evidence goes back decades. A randomized, double-blind, placebo-controlled study published in 1990 showed that growth hormone and IGF-I levels fell significantly during octreotide treatment (PubMed 2229278). A later prospective multicenter dose-response study in 99 patients found mean growth hormone levels dropping from about 33 to 10 micrograms/L at a 300 mcg/day dose (PubMed 7594225).
The approved and documented uses, summarized in the StatPearls review, include:
- Acromegaly — to lower growth hormone and IGF-1 when surgery and radiation are insufficient.
- Carcinoid syndrome — to control flushing and severe diarrhea from metastatic carcinoid tumors.
- VIPomas — to control the watery diarrhea driven by VIP-secreting tumors.
Beyond the label, octreotide is used off-label for several conditions. The best known is acute bleeding from esophageal varices in people with cirrhosis: by suppressing glucagon and other vasodilators it causes splanchnic vasoconstriction and lowers portal pressure, which can slow the bleed as a bridge to endoscopy. It is typically an adjunct rather than a standalone fix, and reviews note its effect is most reliable when paired with endoscopic therapy (Nature Scientific Reports, 2024). Other documented off-label uses include chemotherapy- and AIDS-related diarrhea and hepatorenal syndrome.
Delivery matters here. Short-acting octreotide is given as subcutaneous injections several times a day, while the LAR depot is an intramuscular injection roughly every 28 days with around 60% bioavailability. The newer oral form changed the picture for maintenance dosing in acromegaly.
Common side effects are mostly gastrointestinal — diarrhea, nausea, abdominal discomfort — and the drug is associated with gallstone formation, bradycardia in a notable share of patients, and shifts in blood sugar in either direction because it suppresses both insulin and glucagon.
A note on quality and sourcing
Because octreotide is an approved peptide drug, the legitimate supply is pharmaceutical-grade and dispensed by prescription. Material sold through research-chemical channels sits outside that system, and there is no guarantee a vial labeled "octreotide" matches its label for identity or purity. For any peptide bought outside a pharmacy, a current third-party certificate of analysis (COA) covering identity and purity by mass spec and HPLC is the minimum a buyer should expect. peptideone aggregates vendor COAs and independent rater signals rather than testing anything itself. None of this is an endorsement to use the compound, and research-grade material is labeled not for human consumption.