Tesamorelin: What It Is & What It Does
A laboratory-made copy of GHRH, the body’s own signal for releasing growth hormone, with one change that stops it breaking down so fast.
In short
Your body makes a signal called GHRH that tells the pituitary gland to release growth hormone. Tesamorelin is that signal, built in a laboratory, with a small fatty group added to one end so it survives longer. At 44 amino acids it is a large peptide. Pepcore supplies tesamorelin as a lyophilised powder in 20 mg and 10 mg vials, with a batch number on every one.
Related peptides. Ipamorelin · CJC-1295 With DAC · Mixing guide
What does tesamorelin do?
The short answer.
It tells the pituitary gland to release growth hormone. The body already has a signal for this. It is made in the hypothalamus, just above the pituitary, and it is called growth hormone releasing hormone, or GHRH. Tesamorelin is a laboratory-made copy of it.
So it is not growth hormone. It is the signal one step earlier, which is why the body still sets the amount and the timing. That is the difference most people are asking about.
Where it came from
A short history.
GHRH was hunted for years and turned up in an odd place. In 1982 a team at the Salk Institute in California worked out its structure, not from brain tissue where the amounts are tiny, but from a pancreatic tumour that was producing the same signal in quantity. Within a year it had been shown to trigger growth hormone release in people.
The catch was that natural GHRH falls apart within minutes. An enzyme in the blood called DPP-4 always cuts it in the same place, two amino acids in from one end. Tesamorelin is the answer to that: the same 44 amino acids, with a small fatty group called trans-3-hexenoic acid attached at that end. It sits over the cut site, and the molecule lasts far longer.
The target was pinned down in 1992, when the GHRH receptor on pituitary cells was cloned. That is the piece that explains why the exact shape matters.
The numbers
What is in the vial.
| Name | Tesamorelin |
| Building blocks | 44 amino acids, plus a trans-3-hexenoyl group on one end |
| Molecular formula | C₂₂₁H₃₆₆N₇₂O₆₇S |
| Molecular weight | ~5136 g/mol |
| CAS number | 218949-48-5 |
| Purity | ≥ 99% HPLC |
| Supplied as | Lyophilised powder, 20 mg and 10 mg |
| Shipped from | The Netherlands, within the EU |
Sources
Where the above comes from. Titles are the originals, each links to PubMed.
Rivier J et al. · 1982 · Nature
Characterization of a growth hormone-releasing factor from a human pancreatic islet tumour
Böhlen P et al. · 1983 · Regulatory Peptides
Human growth hormone releasing factor and somatostatin from two pancreatic tumors: isolation and characterization
Thorner MO et al. · 1983 · The Lancet
Human pancreatic growth-hormone-releasing factor selectively stimulates growth-hormone secretion in man
Mayo KE et al. · 1992 · Molecular Endocrinology
Molecular cloning and expression of a pituitary-specific receptor for growth hormone-releasing hormone
Wang Y et al. · 2009 · Expert Opinion on Investigational Drugs
Tesamorelin, a human growth hormone releasing factor analogue
Grunfeld C et al. · 2011 · Nature Reviews Drug Discovery
Tesamorelin
Which tesamorelin?
Three ways to buy it.
| Product | What it is | Amount |
|---|---|---|
| Tesamorelin 20 mg | The peptide on its own, the larger vial and the better value per milligram | 20 mg |
| Tesamorelin 10 mg | The same peptide in a smaller vial | 10 mg |
| Tesamorelin + Ipamorelin | Tesamorelin together with Ipamorelin in one vial | 13 mg total |
Storage and mixing
A long chain needs a gentle hand.
Keep the dry powder cold. At -20 °C it lasts a long time, and a normal fridge is fine for short periods. To mix it, add bacteriostatic water slowly down the inside wall of the vial. Never onto the powder, and never shake it. Roll it gently until it dissolves.
At 44 amino acids this is a long molecule, and long molecules suffer most from shaking and from being frozen and thawed over and over. Handle it once, gently. Our mixing guide goes through it step by step, and the peptide calculator works out the concentration.
Frequently asked
What comes up most often.
What is tesamorelin?
A laboratory-made copy of growth hormone releasing hormone, or GHRH, the signal that tells the pituitary gland to release growth hormone. It is 44 amino acids long with a trans-3-hexenoyl group on one end. All Pepcore products are for laboratory research only.
How is it different from growth hormone?
Growth hormone is the end product. Tesamorelin is the instruction that comes before it. One is the message, the other is what the message asks for.
Why does it have a fatty group on it?
Natural GHRH is broken up within minutes by an enzyme called DPP-4, which always cuts in the same place. The trans-3-hexenoyl group sits over that spot, so the molecule survives far longer. It is the only difference between tesamorelin and the natural version.
How do I store and mix it?
Keep the dry powder cold, at -20 °C for the long term. Add bacteriostatic water slowly down the inside wall of the vial, never straight onto the powder, and never shake it. Avoid freezing and thawing it over and over. The peptide calculator works out concentrations.
Tesamorelin at Pepcore
Lyophilised powder, 20 mg or 10 mg per vial, ≥ 99% HPLC purity, certificate of analysis on request. Shipped within the EU from the Netherlands.
All Pepcore products are intended for laboratory research only. They are not for human or veterinary consumption.
For laboratory research use only – not for human or veterinary use. All Pepcore products are sold strictly as research materials for in vitro use. They are not medicines, supplements, foods or cosmetics. Sold only to adults aged 18 and over.