What Is Tesamorelin? Structure, Mechanism & FDA Status

By Sequora Research Team · Updated October 2026

What is tesamorelin? Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone (GHRH): the full 44-amino-acid human sequence with a six-carbon hexenoyl group added to the N-terminal tyrosine [R1]. It acts on the GHRH receptor of pituitary somatotroph cells. The research-grade peptide sold by suppliers is a laboratory reagent, not the FDA-approved medicine.

This monograph collects the verified chemistry, the receptor pharmacology and the regulatory facts in one place, with every figure linked to its source. It does not cover use in people or animals.

Tesamorelin at a glance

Tesamorelin belongs to the GHRH analogue family. For background on the whole class, see our overview of what GHRH analogues are. The table below lists the identifiers that matter when you check a vial label or a certificate of analysis.

Structure: native GHRH plus one N-terminal modification

The 44-amino-acid backbone

Human GHRH is cut from a 108-residue precursor protein. The mature hormone is residues 32 to 75 of that precursor, a 44-residue chain ending in an amidated leucine [R3]. The US prescribing information states that tesamorelin “is comprised of the 44 amino acid sequence of human GRF” [R1]. So the peptide chain itself is not substituted. This is the key structural difference from shorter analogues built on GHRH(1-29).

The hexenoyl group

The single modification sits at the N-terminus. The label describes it as a hexenoyl moiety, a C6 chain with a double bond at position 3, attached to the tyrosine at position 1 [R2]. The current US labels we opened do not state whether the double bond is cis or trans, so we report only what the label says.

Formula and mass

The label gives the acetate salt formula as C₂₂₁H₃₆₆N₇₂O₆₇S with roughly seven acetate counter-ions. The free-base molecular weight is 5135.9 Da [R1]. PubChem lists the same free-base formula under CID 16137828 [R4]. For a mass-spectrometry identity check, the expected mass is that of the free base, not the salt.

Mechanism: a GHRH receptor agonist

Endogenous GHRH is a hypothalamic peptide. According to the prescribing information, it acts on pituitary somatotroph cells to stimulate the synthesis and pulsatile release of growth hormone (GH) [R1]. In vitro, tesamorelin binds and stimulates human GHRH receptors with potency similar to the endogenous hormone [R1].

The label’s pharmacodynamics section states that tesamorelin stimulates GH secretion and subsequently raises IGF-1 and IGFBP-3 levels [R1]. Some downstream actions of GH are mediated by IGF-1 made in the liver and peripheral tissues, but not all of them [R1].

Two points matter for experimental design:

• Tesamorelin works upstream of GH. It needs a functional GHRH receptor and somatotroph population to produce a GH signal.
• Because it acts through the pituitary, GH release keeps a pulsatile pattern. That differs from adding GH directly to a system.

Current US labels report mean elimination half-lives of about 8 to 11 minutes in healthy subjects, depending on the formulation studied [R2], [R1]. That short half-life is one reason tesamorelin is often compared with long-acting GHRH analogues; see our tesamorelin vs CJC-1295 comparison.

Research history: what human studies measured

Tesamorelin was developed under the code TH-9507 [R5]. Several published clinical studies focused on the GH axis and glucose handling. We summarise what they measured, without extrapolating beyond each study.

GH pulsatility in healthy men (2011)

A two-week study in 13 healthy men measured overnight GH by frequent sampling, IGF-1, and insulin-stimulated glucose uptake by clamp [R6]. The authors reported higher mean overnight GH, larger GH peak area and higher basal GH secretion. IGF-1 rose significantly. Fasting glucose and insulin-stimulated glucose uptake did not change significantly [R6].

Glycaemic control in type 2 diabetes (2017)

A 12-week randomized, placebo-controlled trial enrolled 53 people with type 2 diabetes [R7]. It measured fasting glucose, HbA1c, oral glucose tolerance test responses, IGF-1 and lipids. The authors reported no significant between-group differences in relative insulin response, fasting glucose or HbA1c at week 12 [R7].

These are the published records of what was observed in specific clinical populations. They are not evidence about any research-grade material, and nothing here should be read as a use recommendation.

FDA status: an approved medicine, a separate research reagent

Tesamorelin is an FDA-approved active ingredient. The current US labels give an initial US approval year of 2010 [R1]. The approved indication is the reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy [R1]. The label also states that long-term cardiovascular safety has not been established [R1].

That approval covers one specific, manufactured drug product. It does not extend to research peptides that share the same sequence. A research-use-only (RUO) vial is made and sold as a laboratory reagent. It is not the approved medicine, is not made under the approved application, and is not for human or veterinary use. Our page on RUO peptides explained sets out what that label means in practice.

Sport is a separate rule set. The 2026 WADA Prohibited List names tesamorelin among GHRH analogues in section S2, prohibited at all times [R8].

Tesamorelin 10mg research material: identity and handling

“Tesamorelin 10mg” refers to the net peptide amount in a lyophilized research vial. Sequora’s Tesamorelin 10mg is supplied as a lyophilized powder in a sealed, labelled vial with a batch code. Each batch is third-party tested by HPLC for purity and by mass spectrometry for identity. The certificate of analysis (COA) for a batch is available by email from research@sequorapeptides.com.

When you review a tesamorelin COA, check three things:

1. Identity. The observed mass should match the free-base molecular weight of about 5135.9 Da [R1].
2. Purity. The HPLC trace should show one main peak, with the purity figure for that specific batch.
3. Batch match. The batch code on the COA should match the code on your vial.

Our guide on how to read a peptide COA walks through each section. You can browse related compounds in the GHRH analogues category, and our sermorelin vs tesamorelin vs ipamorelin post compares the three most-studied options.

Tesamorelin FAQ

Is tesamorelin a peptide?

Yes. It is a 44-amino-acid peptide based on the human GHRH sequence, with a hexenoyl group on the N-terminal tyrosine [R1].

Is tesamorelin FDA approved?

Yes, as a specific prescription medicine first approved in the US in 2010 for one indication in HIV-associated lipodystrophy [R1]. Research-use-only tesamorelin is not that medicine and is not approved for any use in people.

How does tesamorelin work?

It is a GHRH receptor agonist. It binds GHRH receptors on pituitary somatotrophs, which stimulates GH synthesis and pulsatile release; IGF-1 rises downstream [R1].

What is the difference between tesamorelin and sermorelin?

Tesamorelin uses the full 44-residue GHRH sequence plus an N-terminal hexenoyl group [R1]. Sermorelin is the shorter GHRH(1-29) fragment, covered in the three-way comparison linked above.

What is the molecular weight of tesamorelin?

The free base is 5135.9 Da, with the formula C₂₂₁H₃₆₆N₇₂O₆₇S [R1].

Is tesamorelin banned in sport?

Yes. WADA lists tesamorelin under GHRH analogues in section S2 of the 2026 Prohibited List, prohibited in and out of competition [R8].

References

1. US National Library of Medicine, DailyMed. Tesamorelin: US prescribing information (current label), revised 3/2025. Set ID 839334d3-8c1d-4c26-9036-2ab524a6ea75. dailymed.nlm.nih.gov
2. US National Library of Medicine, DailyMed. Tesamorelin: US prescribing information (second current label), revised 2/2024. Set ID 3d783378-b02d-4f19-99dd-0fc91a042224. dailymed.nlm.nih.gov
3. UniProt Consortium. UniProtKB P01286: Somatoliberin (GHRH), Homo sapiens. uniprot.org
4. National Center for Biotechnology Information. PubChem Compound Summary for CID 16137828, Tesamorelin. pubchem.ncbi.nlm.nih.gov
5. DrugBank Online. Tesamorelin, DB08869. go.drugbank.com
6. Stanley TL, Chen CY, Branch KL, Makimura H, Grinspoon SK. Effects of a growth hormone-releasing hormone analog on endogenous GH pulsatility and insulin sensitivity in healthy men. J Clin Endocrinol Metab. 2011;96(1):150-158. PMID 20943777. doi:10.1210/jc.2010-1587
7. Clemmons DR, Miller S, Mamputu JC. Safety and metabolic effects of tesamorelin, a growth hormone-releasing factor analogue, in patients with type 2 diabetes: a randomized, placebo-controlled trial. PLoS One. 2017;12(6):e0179538. doi:10.1371/journal.pone.0179538
8. World Anti-Doping Agency. The 2026 Prohibited List (in force 1 January 2026). wada-ama.org

For laboratory research use only. Not for human or veterinary use.