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The short answer
Tesamorelin is a synthetic analog of growth hormone-releasing hormone (GHRH). It acts on the pituitary GHRH receptor, so its downstream effects run through the body's own growth hormone secretion. AOD9604 is a modified version of residues 176-191 at the C-terminal end of human growth hormone. It does not act on the pituitary, and it was designed to study one region of the growth hormone molecule in isolation from the rest.
| AOD9604 | Tesamorelin | |
|---|---|---|
| What it is | Modified hGH fragment (176-191) | GHRH analog |
| Where it acts | Downstream; not via the pituitary | Pituitary GHRH receptor |
| Relationship to GH release | Does not stimulate it | Stimulates endogenous GH pulses |
| Regulatory history | No approved product | Approved drug for a specific indication |
| Evidence stage | Rodent and early human work | Published clinical trials |
Same research area, opposite ends of the axis.
Tesamorelin: working upstream
Tesamorelin is the full 44-amino-acid GHRH sequence with a chemical modification at its N-terminus that makes it more resistant to enzymatic breakdown than native GHRH. Because it acts at the pituitary, the growth hormone it produces is the body's own, released in the normal pulsatile pattern. It is the only compound of the two that has progressed to an approved drug, for a narrowly defined indication, and it has a published clinical trial record as a result.
AOD9604: studying a fragment
AOD9604 takes the 176-191 region of human growth hormone and adds a tyrosine residue. Early rodent research studied this fragment because that region of growth hormone had been associated with metabolic activity, and the published work reported that the fragment did not reproduce growth hormone's broader effects such as raising IGF-1. Later published work includes a rabbit cartilage model and analytical methods for detecting the compound.
Evidence quality
The asymmetry is large. Tesamorelin has published clinical trials and a regulatory review behind it. AOD9604 has a smaller literature, mostly preclinical, and its human development did not result in an approved product. A study design that uses either should set expectations from that record.
Compounds referenced here are supplied as analytical-grade reference materials for in-vitro and laboratory research only. Nothing on this page is a recommendation for human or veterinary use.
Frequently asked questions
What is the difference between AOD9604 and tesamorelin?
Tesamorelin is an analog of growth hormone-releasing hormone that acts on the pituitary to trigger the body's own growth hormone release. AOD9604 is a modified fragment (residues 176-191) of the growth hormone molecule itself and does not act on the pituitary.
Is AOD9604 the same as HGH fragment 176-191?
AOD9604 is based on the 176-191 region of human growth hormone, with an added tyrosine residue. It is a modified version of that fragment rather than an identical copy.
Does AOD9604 raise growth hormone or IGF-1?
AOD9604 does not stimulate growth hormone release, and published rodent research reported that it did not reproduce growth hormone's effect on IGF-1. Tesamorelin, by contrast, works by stimulating growth hormone release.
Which has more published research?
Tesamorelin, by a wide margin. It has published clinical trials and progressed to an approved drug for a specific indication. AOD9604's literature is smaller and mostly preclinical.
Published research
A selection of peer-reviewed and clinical literature indexed on PubMed. Provided so qualified researchers can locate the primary sources — inclusion here is not a claim about any product or outcome.
- Development reviewCurrent Opinion in Investigational Drugs · 2004
AOD-9604 Metabolic
View on PubMed - Animal studyInternational Journal of Obesity and Related Metabolic Disorders · 2001
Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment
View on PubMed - Animal-model studyAnnals of Clinical and Laboratory Science · 2015
Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model
View on PubMed - Peer-reviewed study · 2012
Tesamorelin — overview
View on PubMed - Peer-reviewed studyAIDS (London, England) · 2024
Tesamorelin in HIV patients — clinical study
View on PubMed - Peer-reviewed studyNature reviews. Drug discovery · 2011
Tesamorelin — drug profile
View on PubMed
Continue reading
- AOD9604: What It Is and What It DoesA 16-residue fragment of growth hormone, made to keep the metabolic tail of the molecule without the rest of it.
- Tesamorelin: What It Is and What It DoesTells the body to release its own growth hormone — studied for metabolism and body fat.
- Tesamorelin vs CJC-1295 vs Ipamorelin: GHRH Analogs and SecretagoguesTwo of these are GHRH analogs and one is a ghrelin-receptor secretagogue. Which receptor each engages explains why they are studied together rather than as alternatives.
- Sermorelin vs Tesamorelin vs CJC-1295: Three GHRH Analogs ComparedAll three act at the same receptor. They differ in fragment length, stability and how much published human data stands behind each.
VNG Research Team
VNG Labs supplies analytical-grade reference materials with lot-matched Certificates of Analysis. Our write-ups are neutral, source-cited references for qualified and independent researchers.
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