Pegvisomant
Also known as: Somavert
Key Facts: Pegvisomant
- Category
- Hormonal
- FDA Status
- FDA Approved
- Clinical Status
- FDA Approved - Acromegaly
- Banned in Sport (WADA)
- Not on the WADA Prohibited List (2026).
- Administration
- Subcutaneous injection daily
- Typical Dose
- 10-30 mg daily
- Frequency
- Once daily
- Duration
- Long-term / chronic use
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.
What does the research show?
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.
What doses have been studied?
Typical Dosingⓘ
Community experience
10-30 mg daily
10-40 mg daily
Once daily
A growth hormone receptor antagonist used in acromegaly. Prescription only, with liver function monitoring required.
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
When and how is Pegvisomant taken?
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.
What are the side effects of Pegvisomant?
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
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
Is Pegvisomant banned in sport?
Not on the WADA Prohibited List (2026).
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. Prescription drug. Dose set by prescriber per label. Not medical advice.
Related Peptides
Peptides commonly compared with Pegvisomant or used in similar applications.
Lanreotide
FDALanreotide (development code BIM-23014) 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. The FDA approved it for acromegaly in 2007, for gastroenteropancreatic neuroendocrine tumors in 2014, and for carcinoid syndrome in 2017. Generic versions now exist alongside Ipsen's Somatuline Depot. It is established prescription medicine, not an experimental compound.
HormonalLeuprolide
FDALeuprolide (brand name Lupron) is a synthetic GnRH agonist, a modified peptide far 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 (first US approval 1985), 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.
HormonalHMG
FDAHMG (human menopausal gonadotropin, sold as menotropins under the brand Menopur) is a purified hormone mix extracted from the urine of postmenopausal women. Each standard vial carries 75 IU of FSH activity and 75 IU of LH activity, with most of the LH activity coming from hCG. It is an FDA-approved fertility drug used to stimulate egg development in IVF, and it is also used, mostly off-label in the US, together with hCG to kick-start sperm production in men whose pituitary does not make enough FSH and LH. This one has decades of real clinical use behind it.
HormonalTriptorelin
FDATriptorelin is a synthetic analog of gonadotropin-releasing hormone (GnRH) with a D-tryptophan swapped in at position 6, which makes it far more potent and longer-lasting than the natural hormone. As a long-acting depot it is FDA-approved to shut down testosterone in advanced prostate cancer (Trelstar) and to pause early puberty in children (Triptodur), and in Europe it is sold as Decapeptyl, including a short-acting 0.1 mg form used in IVF. In men's health circles it is known for something else: a single small dose used to 'restart' testosterone after steroid use. That idea rests on very little published evidence.
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