Pegvisomant
Also known as: Somavert
Key Facts: Pegvisomant
- Category
- Hormonal
- FDA Status
- FDA Approved
- Clinical Status
- FDA Approved - Acromegaly
- Administration
- Subcutaneous injection daily
- Typical Dose
- 10-30 mg daily
- Frequency
- Once daily
- Duration
- Long-term / chronic use
Mechanism of Action
Growth hormone normally has to bind two sites on a pair of growth hormone receptors to twist them into the active shape that fires off signaling. Pegvisomant is an engineered growth hormone molecule with mutations that let it grab the receptor with even higher affinity at one site but block productive binding at the second, so the receptor pair cannot form the working complex. No active signal means the liver and other tissues stop making IGF-1, the hormone responsible for most acromegaly symptoms. Because it works at the receptor downstream of the pituitary, it does not shrink the tumor or lower circulating growth hormone, and lab assays for growth hormone can actually read higher. The PEG coating extends its half-life so it can be injected under the skin daily.
Research Summary
Pegvisomant has clear randomized human evidence. The pivotal 12-week trial by Trainer and colleagues in the New England Journal of Medicine in 2000 showed dose-dependent drops in IGF-1, with normalization in up to roughly 90 percent of patients at the highest dose versus about 10 percent on placebo. Longer-term observational and registry data, including the global ACROSTUDY surveillance program, confirm IGF-1 normalization in the majority of patients on adequate doses, making it the most reliable drug for achieving biochemical control. The main monitored risks are liver enzyme elevations, which require periodic blood tests, and the fact that it does not control tumor size, so imaging follow-up is still needed. This is approved, well-characterized therapy with a distinct and clinically valuable mechanism.
Dosing Information
Typical Dosingⓘ
Community experience
10-30 mg daily
10-40 mg daily
Once daily
GH receptor antagonist for acromegaly. Prescription only. Requires monitoring of liver function.
Research Dosingⓘ
Scientific studies
FDA-approved dosing
Doses from Studies
40 mg loading dose
10-30 mg daily maintenance
Duration
Long-term / chronic use
Administration
Subcutaneous injection daily
Timing & Administration
Best Time to Take
Morning or as directed
Follow recommended protocol
Food Recommendation
With or without food
Why This Timing?
Timing may vary based on individual response and goals. Consistency is generally more important than specific timing.
Possible Side Effects
Not everyone experiences these effects. Individual responses vary based on dosage, duration, and personal factors.
- ●Infection
- ●Pain
- ●Nausea
- ●Injection site reactions
- ●Liver toxicity (rare but serious)
- ●Hypoglycemia in diabetics
- ●FDA approved (Somavert)
References
- https://www.nejm.org/doi/full/10.1056/NEJM200004203421604
- https://en.wikipedia.org/wiki/Pegvisomant
- https://go.drugbank.com/drugs/DB00082
- https://pubmed.ncbi.nlm.nih.gov/10984267/
Research This Peptide Further
Frequently Asked Questions
What does Pegvisomant do?
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.
How does Pegvisomant work?
Growth hormone normally has to bind two sites on a pair of growth hormone receptors to twist them into the active shape that fires off signaling. Pegvisomant is an engineered growth hormone molecule with mutations that let it grab the receptor with even higher affinity at one site but block productive binding at the second, so the receptor pair cannot form the working complex. No active signal means the liver and other tissues stop making IGF-1, the hormone responsible for most acromegaly symptoms. Because it works at the receptor downstream of the pituitary, it does not shrink the tumor or lower circulating growth hormone, and lab assays for growth hormone can actually read higher. The PEG coating extends its half-life so it can be injected under the skin daily.
Is Pegvisomant FDA approved?
Yes, Pegvisomant is FDA approved. FDA Approved - Acromegaly
What are the side effects of Pegvisomant?
Reported side effects include: Infection, Pain, Nausea, Injection site reactions, Liver toxicity (rare but serious). Individual responses vary based on dosage, duration, and personal health factors.
What is the typical dose of Pegvisomant?
Community-reported common dose: 10-30 mg daily (Once daily). Range: 10-40 mg daily. Administration: Subcutaneous injection daily. Community-reported doses. Not medical advice. Consult healthcare provider.
Related Peptides
Peptides commonly compared with Pegvisomant or used in similar applications.
Lanreotide
FDALanreotide 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.
HormonalGonadorelin
FDAGonadorelin 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.
HormonalLeuprolide
FDALeuprolide (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.
HormonalOctreotide
FDAOctreotide 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).
HormonalMacimorelin
FDAMacimorelin (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.
HormonalKisspeptin
Clinical TrialsKisspeptin 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.
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