Tesamorelin: A Chart of One Night's Pulses
Tesamorelin is a lab-made version of growth hormone-releasing hormone (GHRH), the signal the brain sends to the pituitary gland to release growth hormone. It's the full 44-amino-acid GHRH chain with a small six-carbon cap on its first amino acid.1,2 Its research story is about rhythm: growth hormone comes out in pulses, like a lighthouse's flashes, and tesamorelin makes each pulse carry more without changing how often they come.3
| Name | Structure | Mass | Formula | Registry |
|---|---|---|---|---|
| TesamorelinTH9507; sold as EGRIFTA | GHRH(1-44) with a trans-3-hexenoyl cap | 5136 g/mol | C221H366N72O67S | CAS 218949-48-5PubChem CID 16137828 |
Identity: 1
The Keeper's Signal
In the body, GHRH is made in the hypothalamus and carried a short distance to the pituitary gland. There it binds GHRH receptors on somatotroph cells, the cells that make growth hormone, and they release it.4 In lab tests, tesamorelin binds and switches on human GHRH receptors with about the same potency as natural GHRH.4
The difference is the cap. Natural GHRH is cut apart quickly in blood by an enzyme called DPP-4. Theratechnologies, a Montreal company, added a trans-3-hexenoyl group to its first amino acid and called the result TH9507. The capped peptide resisted DPP-4 and broke down more slowly in rat, dog and human plasma, and growth hormone and IGF-1 rose markedly in rats, dogs and pigs.2
The Light List, Kept Overnight
The natural rhythm
Growth hormone isn't released in a steady stream. The pituitary sends it out in bursts, with a lower flow between them. In 2011 a team at Massachusetts General Hospital took blood every 10 minutes overnight, from 8 pm to 7:40 am, in 13 healthy men, and mapped every burst.3
Two weeks later: more, not faster
After two weeks of daily tesamorelin, each burst carried more growth hormone and the flow between bursts was higher. The number of bursts didn't change, and neither did the highest level reached overnight: more light from each flash, without a brighter peak. IGF-1 rose by an average of 181 µg/L.3
Two weeks after stopping
Two weeks after the last day, the overnight pattern had returned to where it started, apart from a small change in how long growth hormone lasted in blood. IGF-1 fell back to levels that didn't differ from the start.3
Schematic of the 2011 study's pattern, not its data: the pulses keep the same timing and tallest peak, and after two weeks they are broader with a higher floor between them.
The Tide Comes In
Growth hormone works partly through a second messenger. The liver and other tissues answer it by making IGF-1, along with its carrier protein IGFBP-3, and the US label lists both as rising when tesamorelin raises growth hormone.4 No other pituitary hormone it checked changed in a clinically significant way.4 Trials report IGF-1 as a readout; these gauges show three of them.
The first two gauges share a scale in percent change; the third is in µg/L, so it isn't comparable with them.
What's Been Done in People
Tesamorelin became a prescription medicine, so it has a body of human trials. The largest enrolled adults with HIV, the group the approved medicine is for. This guide reports only their hormone measurements.
Early study, 2005
A placebo-controlled study in adults with HIV compared different amounts.10
Phase 3, 2007
412 adults with HIV, 26 weeks, placebo-controlled. IGF-1 rose 81% on tesamorelin and fell 5% on placebo.5,6
Healthy men, 2011
13 men, two weeks, with blood taken every 10 minutes overnight to map each growth hormone pulse.3
Older adults, 2012
152 adults aged 55 to 87, 20 weeks, placebo-controlled. IGF-1 rose 117% and stayed in the physiological range.7
Theratechnologies developed tesamorelin, and its scientists published the early lab and animal profile. Later work includes academic studies such as the 2011 pulse study at Massachusetts General Hospital, and a 2026 review pooled the trials in people with HIV.2,3,11
The Research So Far
| 2004 | Early TH9507 work in dogs, including delivery to the lungs. 12 |
|---|---|
| 2005 | A placebo-controlled study in adults with HIV. 10 |
| 2007 | Lab and animal profile published; the 412-person phase 3 trial is published. 2,5,6 |
| 2010 | The FDA approves it as EGRIFTA, a prescription medicine. 9 |
| 2011 | The overnight pulse study in healthy men; a full review of the drug. 3,13 |
| 2012 | A 20-week trial in older adults. 7 |
| 2015 | EGRIFTA goes on the market in Canada; a population model of how the body handles it is published. 14,15 |
| 2022 | The Canadian EGRIFTA listing is cancelled. 14 |
| 2026 | A systematic review and meta-analysis pools the trials in people with HIV. 11 |
Where It Stands
An approved prescription medicine in the US, no longer marketed in Canada, and prohibited in sport.
United States
The FDA approved tesamorelin in November 2010 as EGRIFTA, a prescription medicine for a specific use in adults with HIV. Newer versions remain on the US market.4,9
Health Canada
EGRIFTA was marketed in Canada from 2015. Both of its Canadian listings are now cancelled, so no tesamorelin product is currently marketed here. It isn't among the peptides named in Health Canada's April 2026 advisory.14,16
Sport
WADA's Prohibited List names tesamorelin among the GHRH analogues in section S2.2.4, prohibited at all times.17
Reading a Tesamorelin COA
What a batch report for a 44-amino-acid peptide should show.
Identity
Mass spectrometry should match about 5136 g/mol (monoisotopic about 5134.7). A peptide this size shows several charge states, so the report should give the reconstructed mass.1
The cap
Tesamorelin is GHRH(1-44) with a trans-3-hexenoyl group on its first amino acid. The measured mass should match the capped peptide, not plain GHRH.2
Purity and content
HPLC shows what share of the peptide signal is the intended sequence. Peptide content says how much of the powder is peptide rather than salt and water.
Endotoxin
The LAL test measures bacterial endotoxin, which can skew cell-based experiments.
Batch Reports You Can Verify
Every batch independently lab-tested: identity, purity and LAL endotoxin. Batch-linked COAs you can verify directly with the testing lab.
Common Tesamorelin Research Questions
What is tesamorelin?
A lab-made version of the 44-amino-acid hormone GHRH with a small trans-3-hexenoyl cap on its first amino acid. It binds the same receptor as natural GHRH.1,4
Is tesamorelin the same as EGRIFTA?
EGRIFTA is the brand name of the approved prescription medicine made from tesamorelin. TH9507 was its development code.2,9
What does the cap do?
It made the peptide resist DPP-4, the enzyme that quickly cuts natural GHRH, and it broke down more slowly in rat, dog and human plasma in lab tests.2
Does it change how often growth hormone pulses come?
Not in the 2011 study. The pulses carried more growth hormone and the level between pulses rose, but the number of pulses and the overnight peak didn't change.3
How long does it last in blood?
Minutes. The US label for EGRIFTA SV gives a mean half-life of about 8 minutes in healthy adults. Its effect is read through growth hormone and IGF-1.4
Has it been tested in people?
Yes. About 24 studies are registered, including a 412-person phase 3 trial in adults with HIV.6,8
Is tesamorelin approved in Canada?
EGRIFTA was marketed in Canada from 2015, but both of its Canadian listings are now cancelled, so no tesamorelin product is currently marketed here.14
Is tesamorelin banned in sport?
Yes. WADA names it among the GHRH analogues in section S2.2.4, prohibited at all times.17
Abbreviations and Terms
Fl W 3·2s
Chart notation for a light: flashing (Fl), white (W), repeating every 3.2 seconds. The pituitary's light on this chart is drawn that way.
LFl
Long-flashing: a light whose flashes last at least two seconds. It marks the broader pulses after two weeks.
GHRH
Growth hormone-releasing hormone, made in the hypothalamus; it tells the pituitary to release growth hormone.
Somatotroph
A pituitary cell that makes and releases growth hormone.
Pulsatile release
Release in bursts rather than a steady stream. Growth hormone comes out this way.
Pulse area
How much hormone one burst carries: its height and how long it lasts, taken together.
IGF-1 and IGFBP-3
Insulin-like growth factor 1, made mainly in the liver in answer to growth hormone, and the main protein that carries it in blood.
DPP-4
Dipeptidyl peptidase-4, an enzyme that trims the first two amino acids off peptides such as GHRH.
Half-life
The time it takes for half of a substance to clear from blood.
HPLC and LAL
HPLC separates a sample to measure purity. The LAL test detects bacterial endotoxin.
References
- PubChem. Tesamorelin, CID 16137828 (C221H366N72O67S; CAS 218949-48-5). pubchem.ncbi.nlm.nih.gov
- Ferdinandi ES et al. (2007). Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue. Basic & Clinical Pharmacology & Toxicology 100:49–58. PubMed 17214611
- Stanley TL et al. (2011). Effects of a growth hormone-releasing hormone analog on endogenous GH pulsatility and insulin sensitivity in healthy men. Journal of Clinical Endocrinology & Metabolism 96:150–158. PubMed 20943777
- U.S. National Library of Medicine, DailyMed. EGRIFTA SV (tesamorelin) prescribing information, sections 12.1–12.3. dailymed.nlm.nih.gov
- Falutz J et al. (2007). Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine 357:2359–2370. PubMed 18057338
- ClinicalTrials.gov. NCT00123253: TH9507 in patients with HIV-associated lipodystrophy (phase 3, 412 enrolled). clinicaltrials.gov
- Baker LD et al. (2012). Effects of growth hormone–releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults: results of a controlled trial. Archives of Neurology 69:1420–1429. PubMed 22869065
- ClinicalTrials.gov. Search for tesamorelin (24 registered studies), October 2026. clinicaltrials.gov
- U.S. Food and Drug Administration, Drugs@FDA. EGRIFTA (tesamorelin), application 022505, original approval November 10, 2010. accessdata.fda.gov
- Falutz J et al. (2005). A placebo-controlled, dose-ranging study of a growth hormone releasing factor in HIV-infected patients with abdominal fat accumulation. AIDS 19:1279–1287. PubMed 16052083
- Ditta AM et al. (2026). Efficacy and safety of tesamorelin in people living with HIV (PLWH) with lipodystrophy: a systematic review and meta-analysis. Journal of the International Association of Providers of AIDS Care 25:23259582261475549. PubMed 42538058
- Jansen M et al. (2004). Pulmonary delivery of TH9507, a growth hormone-releasing factor analogue, in the dog. International Journal of Pharmaceutics 276:75–81. PubMed 15113616
- Dhillon S (2011). Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy. Drugs 71:1071–1091. PubMed 21668043
- Health Canada, Drug Product Database. EGRIFTA, DIN 02423677 (cancelled pre-market, 2023) and DIN 02438712 (marketed 2015, cancelled post-market 2022), checked October 2026. health-products.canada.ca
- González-Sales M et al. (2015). Population pharmacokinetic analysis of tesamorelin in HIV-infected patients and healthy subjects. Clinical Pharmacokinetics 54:285–294. PubMed 25358450
- Health Canada (April 9, 2026). Think twice before injecting peptides bought online: unauthorized products can seriously harm your health. recalls-rappels.canada.ca
- World Anti-Doping Agency. The Prohibited List, S2.2.4 Growth hormone releasing factors (checked October 2026). wada-ama.org
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