Tesamorelin
Egrifta
Tesamorelin (Egrifta) is a synthetic, stabilized analog of human growth hormone-releasing hormone (GHRH 1-44) given as a daily subcutaneous injection. Its only condition with adequate human data is reduction of excess visceral (belly) fat in HIV-associated lipodystrophy, where randomized trials show it lowers visceral adipose tissue by roughly 15-18% and modestly improves triglycerides/cholesterol; a separate RCT shows it also reduces liver fat in HIV-associated NAFLD. It works indirectly by stimulating the pituitary to release the body's own growth hormone, raising IGF-1. The main risks are that it raises IGF-1 (a growth-promoting hormone), which underlies its main safety concerns and its contraindication in active cancer and in disorders of the pituitary/hypothalamus; it can cause fluid retention, joint pain, peripheral edema, carpal-tunnel-type symptoms, and injection-site reactions; and although controlled HIV and type-2-diabetes trials did not show meaningful worsening of glucose control at 6-12 months, growth-hormone-axis stimulation can theoretically impair insulin sensitivity, so glucose must be monitored. Benefit is not durable: visceral fat re-accumulates rapidly once the drug is stopped. There are no data supporting use for bodybuilding, anti-aging, or in healthy adults, and no cardiovascular or cancer outcome trials.
Mechanism of action
Pharmacokinetics
Short: approximately 26-38 minutes in plasma (reported ~38 min in HIV-infected patients); the biological effect is mediated downstream via the GH/IGF-1 axis, so IGF-1 elevation persists far longer than the parent peptide.
Dosed once daily by subcutaneous injection reflecting rapid clearance of the peptide; IGF-1 rises over weeks of continued dosing and falls after discontinuation, with visceral fat re-accumulating within months of stopping.
Subcutaneous injection, 2 mg once daily as studied in the pivotal HIV lipodystrophy and NAFLD trials (dose reported here only with its attached risks and monitoring requirements, not as an optimization target).
As a peptide it is degraded to smaller peptide fragments and amino acids by peptidases; no clinically dominant single organ of elimination is described. Renal/hepatic impairment PK is not well characterized in the primary literature.
For monitoring and washout planning, not drug-test evasion.
Physiological & performance effects
- Reduces visceral adipose tissue (VAT) by ~15-18% over 6-12 months in HIV-associated abdominal fat accumulation (RCTs and pooled phase-3 analysis)
- Reduces trunk fat, waist circumference, and waist-to-hip ratio without significant loss of subcutaneous or limb fat
- Lowers triglycerides and total-cholesterol-to-HDL ratio; modest improvement in total and HDL cholesterol
- Raises IGF-1 substantially (approximately 80-115% increase from baseline)
- Reduces hepatic fat fraction in HIV-associated NAFLD (~37% relative reduction; more patients reaching hepatic fat <5%) and was associated with prevention of fibrosis progression
- Improves patient- and physician-rated body image/belly-profile distress measures
- Benefit is not durable: visceral fat re-accumulates rapidly after discontinuation
- In older adults with/without mild cognitive impairment, 20 weeks of GHRH improved some cognitive (executive function) measures and reduced percent body fat — investigational, not an approved use
Adverse effects by system
No cardiovascular outcome trials exist. Fluid retention and peripheral edema occur and could raise blood pressure or unmask heart failure; IGF-1 elevation is a theoretical concern. Surrogate lipid markers (triglycerides, cholesterol/HDL ratio) improved in trials. Net long-term cardiovascular risk/benefit is unproven.
No signal of drug-induced liver injury; on the contrary, an RCT in HIV-associated NAFLD showed reduced hepatic fat and a substudy suggested favorable shifts in fibrosis-related gene expression. Direct hepatotoxicity has not been reported.
Primary endocrine effect is stimulation of the GH/IGF-1 axis, raising IGF-1 by ~80-115%; sustained supraphysiologic IGF-1 is the central safety concern. It can impair insulin sensitivity in theory (GH counter-regulatory effect); controlled HIV and type-2-diabetes trials did not show clinically meaningful worsening of fasting glucose or HbA1c from 6-12 weeks out to 52 weeks, though fasting insulin rose ~35% in one cognition trial in MCI subjects. Contraindicated where the hypothalamic-pituitary axis is disrupted.
No direct gonadal/reproductive toxicity established; it is not a sex steroid and does not act on the gonadal axis. It is contraindicated in pregnancy (growth-factor effects; no benefit) and has not been studied in pregnancy or lactation.
No consistent psychiatric adverse-effect signal in the HIV trials. A GHRH cognition RCT reported generally favorable or neutral cognitive effects; depression/mood destabilization is not an established effect but data in non-HIV populations are limited.
No characteristic direct nephrotoxicity reported in the primary literature; fluid retention is mediated by GH-axis sodium/water retention rather than renal injury. Renal-impairment data are limited.
No characteristic hematologic toxicity reported in the trials; no meaningful hematologic effect described.
Injection-site reactions are the most common local effect (erythema, pruritus, pain, bruising, urticaria/rash); more frequent than placebo in the NAFLD RCT though not judged serious.
HPTA suppression & recovery
Suppression: Not a hypothalamic-pituitary-gonadal (HPTA/testosterone-axis) suppressant; the relevant axis is somatotropic (GH/IGF-1). It stimulates rather than suppresses GH release.
Tesamorelin does not suppress the testosterone/gonadal axis and no SERM-based restart is relevant to its mechanism. Its endocrine action is on the GH/IGF-1 axis: IGF-1 rises during use and falls after stopping, and visceral fat re-accumulates. Anyone with pre-existing pituitary/hypothalamic disease, prior pituitary surgery/irradiation, or concerns about their endocrine axis should be evaluated and managed by an endocrinologist before and during use; do not self-manage GH-axis or any hormonal recovery.
Monitoring
Cadence: Baseline before starting, then approximately every 3 months during the first year (IGF-1, glucose/HbA1c, lipids), and periodically thereafter or sooner if symptoms of fluid retention, joint problems, or rising glucose develop; all interpretation and dose decisions by the prescribing clinician/endocrinologist.
- New or worsening peripheral edema, swelling, or rapid weight gain (fluid retention)
- Joint pain, muscle pain, or numbness/tingling and hand pain suggesting carpal tunnel syndrome
- Persistent headache, visual changes, or vision loss
- Rising blood glucose, increased thirst/urination, or loss of diabetes control
- Severe or persistent injection-site reaction, rash, or signs of allergic reaction (hives, swelling, difficulty breathing)
Contraindications
- Active malignancy (any active neoplasm) — GH/IGF-1 stimulation is growth-promoting; label-based/mechanistic contraindication
- Disruption of the hypothalamic-pituitary axis: hypophysectomy, hypopituitarism, pituitary tumor or surgery, head irradiation, or significant head trauma
- Pregnancy (no benefit; growth-factor exposure) and not studied in breastfeeding
- Known hypersensitivity to tesamorelin or mannitol (excipient)
- Caution / relative contraindication in diabetes mellitus and in pre-existing diabetic retinopathy given GH-axis effects on glucose and potential to worsen retinopathy
- Not indicated or studied in healthy adults, for bodybuilding, athletic performance, or anti-aging
Interaction profile
- MajorWith insulin: Metabolic / glucose
- ModerateWith another GH secretagogue: Metabolic / glucose
- ModerateWith growth hormone: Metabolic / glucose
- ModerateWith IGF-1: Metabolic / glucose
- ModerateWith a GLP-1 / incretin agonist: Metabolic / glucose
- ContraindicatedWith DNP: Additive cardiovascular strain
Check a specific combination in the interaction checker.
Reducing harm & when to stop
- Only use under clinician supervision; the only condition with adequate human evidence is HIV-associated visceral fat accumulation (and investigationally HIV-associated NAFLD). There is no evidence base for use in healthy adults, athletes, or for anti-aging.
- Get baseline and periodic bloodwork (IGF-1, fasting glucose, HbA1c, lipids) and age-appropriate cancer screening before starting; have an endocrinologist involved, especially if you have diabetes, prediabetes, or any pituitary/hypothalamic condition.
- Do not use if you have an active cancer, a pituitary/hypothalamic disorder, or are or may become pregnant.
- Stop and seek medical care for: signs of increasing fluid retention or swelling, new or worsening joint pain, numbness/tingling or carpal-tunnel symptoms, persistent headache or visual changes, rising blood sugars, or a severe injection-site or allergic reaction.
- Rotate injection sites to limit local skin reactions.
- Understand the benefit is not durable — visceral fat re-accumulates after stopping — so this is not a one-time fix, and long-term (multi-year) safety, cardiovascular, and cancer outcomes have not been established.
- This monograph is harm-reduction information, not medical advice or an endorsement of use; decisions should be made with a qualified clinician.
Citations (10)
Every clinical claim above is tied to a primary source. Overall evidence grade A — graded to the best available evidence for its core claims.
- 01
Tesamorelin 2 mg SC daily for 26 weeks reduced visceral adipose tissue (~15%) and improved triglycerides and total-cholesterol/HDL ratio, raised IGF-1 by ~81%, with no significant change in glucose measures, in HIV patients with abdominal fat accumulation.
RCTMetabolic effects of a growth hormone-releasing factor in patients with HIV.PMID 18057338 ↗
- 02
In a 12-month RCT with randomized-withdrawal extension, tesamorelin reduced VAT ~10.9% at 6 months and ~18% at 12 months with no change in glucose; VAT was rapidly lost (re-accumulated) after switching from tesamorelin to placebo.
- 03
Pooled analysis of two multicenter double-blind phase-3 trials (n=806) confirmed ~15% VAT reduction, preserved subcutaneous fat, improved triglycerides and cholesterol/HDL ratio, IGF-1 increase (~108 ng/mL), maintenance of effect to 52 weeks, and no clinically meaningful glucose changes; drug generally well tolerated.
Meta-analysisDOI 10.1210/jc.2010-0490 ↗
- 04
Reduction in visceral fat with tesamorelin was associated with improved triglycerides, adiponectin, and preservation of glucose homeostasis over 52 weeks in responders (phase-3 randomized data).
- 05
Review of tesamorelin pharmacology and tolerability: short plasma half-life (~26-38 min), most adverse events are injection-site reactions or GH-associated effects (arthralgia, headache, peripheral edema/fluid retention); serious adverse events in <4% over 26 weeks.
- 06
In a 12-week randomized placebo-controlled trial in patients with type 2 diabetes, tesamorelin (1 or 2 mg) did not significantly alter insulin response, fasting glucose, or HbA1c/glycemic control, and lowered total and non-HDL cholesterol.
- 07
In a randomized, double-blind trial in HIV-associated NAFLD, tesamorelin 2 mg daily reduced hepatic fat fraction (~37% relative reduction; 35% vs 4% reached HFF<5%) without differences in fasting glucose or HbA1c; injection-site complaints were more common than placebo.
- 08
Paired-liver-biopsy substudy showed tesamorelin increased oxidative-phosphorylation gene sets and decreased inflammation, tissue-repair, and cell-division gene sets, with changes correlating with improved fibrosis-related gene score.
- 09
GHRH/tesamorelin administration raised IGF-1 (~117%), reduced percent body fat, and increased fasting insulin ~35% in adults with mild cognitive impairment; cognitive effects were generally favorable — supports GH/IGF-1 axis and glucose-related effects.
- 10
Predictors of VAT response and threshold VAT<140 cm2 were analyzed across two phase-3 tesamorelin trials, supporting reproducibility of the VAT-lowering effect.
Last reviewed 2026-07-06 · Verified against PubMed · Educational, not medical advice