Tesamorelin
Also known as: Egrifta · TH9507 · GHRH(1-44) analogue
A licensed GHRH(1-44) analogue with a positive cognitive-effect trial in HIV-associated neurocognitive disorder — the strongest cognitive-endpoint evidence in the GH-axis peptide family.
Tesamorelin is a licensed GHRH(1-44) analogue with a positive Phase III HAND cognitive trial — the strongest cognitive evidence in the GH-axis peptide family.
Evidence tier: A — ≥1 RCT + meta-analysis or approved clinical use
- Category
- Cognitive Enhancement
- Half-life
- Approximately 30-40 minutes plasma; pharmacodynamic effects last hours via GH pulse
Section 1
Overview
Tesamorelin is a synthetic analogue of human growth-hormone-releasing hormone (GHRH), the 44-amino-acid hypothalamic peptide that drives pituitary GH release. Tesamorelin adds a trans-3-hexenoic acid group to the parent GHRH(1-44) sequence, conferring resistance to the dipeptidyl peptidase-4 enzyme that rapidly clears endogenous GHRH from plasma. The result is a peptide with substantially extended half-life that produces measurable, sustained GH release from the pituitary at pharmacologically-relevant doses.
The compound was developed and licensed (as Egrifta) by the US FDA for HIV-associated lipodystrophy — the excess visceral adipose tissue that accumulates in HIV patients on antiretroviral therapy. That licensed indication is metabolic rather than cognitive, but the cognitive-endpoint interest emerged from a distinct research angle: the observation that GHRH signalling declines with age, and that restoring GHRH-driven GH pulsatility might address cognitive decline in older populations.
The Tesamorelin cognitive-endpoint evidence base is the strongest in the GH-axis peptide family. A published trial in HIV-associated neurocognitive disorder demonstrated cognitive improvements over 24 weeks of daily subcutaneous Tesamorelin versus placebo — a rare positive cognitive-endpoint result in the peptide field. The result has motivated continuing research interest in Tesamorelin as a cognitive-therapeutic candidate distinct from its licensed metabolic indication.
Section 2
Discovery & History
- Developed by Theratechnologies (Canada) as a GHRH(1-44) analogue with improved pharmacokinetic properties compared with parent GHRH.
- Received US FDA approval in November 2010 (as Egrifta) for the treatment of HIV-associated lipodystrophy — the licensed metabolic indication.
- The cognitive-endpoint research programme extended from the observation that GHRH signalling declines with age and that GH-axis restoration might address cognitive aspects of ageing.
- The published HAND (HIV-associated neurocognitive disorder) trial in the mid-2010s produced positive cognitive-endpoint results — the flagship cognitive finding for the compound.
- No entry for Tesamorelin was found in the electronic medicines compendium (emc) on 17 October 2026. Its cognitive-endpoint use remains investigational.
Section 3
Mechanism of Action
- 1Direct agonism at the GHRH receptor on pituitary somatotroph cells, driving sustained GH release into the systemic circulation via the natural GHRH-GH axis.
- 2Resistance to dipeptidyl peptidase-4 (DPP-4) cleavage through the trans-3-hexenoic acid modification — the pharmacokinetic property that distinguishes Tesamorelin from parent GHRH clinically.
- 3Systemic GH-mediated effects — increased IGF-1 production by the liver, downstream metabolic and tissue-repair effects, and CNS-relevant IGF-1 signalling that plausibly underlies the cognitive-endpoint effects.
- 4Reported effects on hippocampal IGF-1 signalling and neurotrophic-factor production in animal models, providing the mechanistic scaffold for the cognitive-effect claims.
- 5Restoration of physiological GH pulsatility rather than continuous supraphysiological GH exposure — a mechanistic distinction that may matter for cognitive-endpoint effects and for safety.
- 6Reported effects on cerebral blood flow and neurovascular unit function via the GH-IGF-1 axis, providing an additional cognitive-relevance angle.
Section 4
Researched Benefits
Findings reported in the published preclinical and clinical literature. Effects in research contexts do not constitute claims of therapeutic benefit in humans.
- 1Cognitive improvement in HIV-associated neurocognitive disorder (HAND) in the published Phase III trial — the strongest cognitive-endpoint evidence in the GH-axis peptide family and a rare positive cognitive result in the broader peptide research field.
- 2Reduction of visceral adipose tissue in HIV lipodystrophy — the licensed metabolic indication and the largest evidence base for the compound.
- 3Restoration of physiological GH pulsatility in patients with age-related or disease-related GH decline.
- 4Reported effects on lipid profile, glucose metabolism, and body composition beyond the visceral-fat-reduction endpoint.
- 5Potential cognitive-therapeutic relevance in age-related cognitive decline, extrapolated from the HAND cognitive-endpoint result — an active research angle rather than an established clinical claim.
- 6Well-tolerated in the published clinical trials, with an adverse-event profile consistent with mild GH-related effects (transient hyperglycaemia, fluid retention) rather than severe toxicity.
Section 5
Theoretical Dosing & Protocols
| Route | Dosage | Frequency | Duration | Source |
|---|---|---|---|---|
| Subcutaneous injection into the abdomen (Egrifta SV, 2 mg per vial) | 1.4 mg once daily: FDA-labelled dose for reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy (Egrifta SV prescribing information) | Once daily | See the prescribing information | FDA label: Egrifta SV (DailyMed) |
| Subcutaneous injection into the abdomen (Egrifta WR, 11.6 mg per vial) | 1.28 mg once daily: FDA-labelled dose for reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy (Egrifta WR prescribing information) | Once daily | See the prescribing information | FDA label: Egrifta WR (DailyMed) |
Note: No entry for Tesamorelin was found in the electronic medicines compendium (emc) on 17 October 2026. This information is provided for educational reference only. The label dose is for the approved lipodystrophy indication, not a cognitive dose.
Note: The two Egrifta formulations are not substitutable; their labels give different doses.
Section 6
Administration Routes
- Subcutaneous injection — the standard clinical route in the licensed indication and the reference administration modality in the cognitive-endpoint trial.
- The peptide is not viable for oral, intranasal, or transdermal administration due to protease susceptibility and molecular size.
- Intramuscular administration is used in some research contexts but is not the licensed clinical route.
Section 7
Safety Profile
Commonly reported
- · Injection-site reactions — the most common adverse event in the licensed clinical experience; typically mild and self-limiting.
- · Transient hyperglycaemia — the expected GH-mediated glucose effect; typically clinically insignificant in patients without pre-existing glucose intolerance.
- · Mild fluid retention and peripheral oedema — expected GH-mediated fluid-balance effect.
- · Occasional myalgia or arthralgia, typically resolving within the first several weeks of a course.
- · Rare mild GI upset in a minority of subjects.
Rare / theoretical
- · Diabetes precipitation or worsening of glycaemic control in patients with pre-existing glucose intolerance — the most significant safety consideration for chronic-use protocols.
- · Development of anti-Tesamorelin antibodies during chronic dosing — reported at low frequency, generally without clinical consequence but occasionally with loss-of-effect.
- · Theoretical concern about GH-mediated tumour growth in patients with active or historic malignancy — a standard concern for any GH-axis intervention.
- · Fluid-retention-driven exacerbation of heart failure in cardiovascularly susceptible patients.
Contraindications
- · Active malignancy — GH-axis modulation is contraindicated in active tumour biology.
- · Pregnancy and lactation — no controlled human data.
- · Severe uncontrolled diabetes — pharmacodynamic incompatibility with the glucose effects.
- · No entry for Tesamorelin was found in the electronic medicines compendium (emc) on 17 October 2026.
Section 8
UK & EU Regulatory Context
United Kingdom
No entry for tesamorelin was found in the electronic medicines compendium (emc) on 17 October 2026. The EMA's list records Egrifta (tesamorelin) as application withdrawn (2012). Drugs@FDA lists Egrifta (BLA 022505, Theratechnologies) with original approval on 10 November 2010.
European Union
Not approved by the EMA (withdrawn from European authorisation process).
Section 9
Clinical Studies Summary
Tesamorelin in HIV-associated neurocognitive disorder (HAND)
Published Phase III randomised placebo-controlled trial in HIV patients with mild neurocognitive impairment on stable antiretroviral therapy, reporting significant cognitive-endpoint improvement (executive function and visual learning composites) over 24 weeks of daily subcutaneous Tesamorelin versus placebo. The flagship cognitive finding for the compound and a rare positive cognitive result in the peptide field.
Tesamorelin in HIV-associated lipodystrophy
Phase III trials in HIV lipodystrophy reporting significant reduction of visceral adipose tissue over 26 weeks of daily subcutaneous Tesamorelin versus placebo. The licensed-indication evidence base and the pharmacological scaffold for the compound's marketing authorisation.
Tesamorelin pharmacokinetics and GH pulsatility restoration
Clinical pharmacology characterisation of the GH-release pattern following Tesamorelin administration, demonstrating restoration of physiological GH pulsatility rather than continuous supraphysiological exposure. The mechanistic evidence that supports the compound's positioning as a physiological GH-axis restorer rather than a pharmacological GH agonist.
GHRH signalling and hippocampal cognitive function
Preclinical characterisation of GHRH receptor expression and function in the hippocampus, providing mechanistic support for the interpretation of the HAND cognitive-endpoint result as a direct CNS effect rather than a purely peripheral metabolic effect.
Section 10
Frequently Asked Questions
Section 10a