regulatory status raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-07. Anything still debated is marked as such rather than presented as settled.
The fragment includes residues that can form an internal disulfide bond between two cysteine positions. This structural feature can influence how the peptide folds and how stable it is in solution. AOD-9604 differs from full-length hGH in size and receptor interactions; it does not contain the entire growth hormone sequence. Published descriptions sometimes use slightly different residue numbering, so sequence information should be checked against primary sources. The molecule is small compared with intact hGH, which affects analytical detection and purification approaches.
Interest in AOD-9604 arose from attempts to separate metabolic effects from growth effects attributed to hGH. Early work explored whether the fragment could influence lipolysis or fat oxidation without promoting growth. Those questions remain partly unresolved because human data are limited and results have varied across studies. The peptide is not a hormone replacement for hGH and is not equivalent to hGH in clinical use. Its research history includes both laboratory studies and commercial marketing claims that are not the same as regulatory approval.
AOD-9604 is a synthetic peptide whose sequence matches the C-terminal fragment of human growth hormone, specifically residues 176 through 191. This region differs from the full hormone in its receptor interactions. The peptide is not a growth hormone secretagogue and does not bind the growth hormone receptor in the same manner. Researchers have examined it for effects on lipid metabolism, but its exact pharmacological profile remains an active area of study.
Development of AOD-9604 began in the 1990s as scientists sought to isolate metabolic effects of growth hormone without its growth-promoting actions. Early laboratory work focused on fat cells and animal models. Several human trials followed, examining changes in body composition and fat mass. Results have been mixed, and the peptide has not progressed to widespread clinical approval. Interest continues in research settings, particularly regarding its mechanism and potential metabolic targets.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Based on the C-terminal region of human growth hormone. |
| Amino acid length | 16 residues | Often described as hGH fragment 176-191. |
| Appearance | Lyophilized powder | Typically white to off-white; exact appearance depends on grade. |
| Solubility | Soluble in water | Aqueous solubility depends on pH, ionic strength, and preparation. |
| Typical storage | -20 °C or lower | Lyophilized peptide is usually kept cold and dry; solutions may require freezing. |
Proposed mechanism focuses on lipolysis, the breakdown of stored triglycerides into free fatty acids and glycerol. AOD-9604 is thought to act on adipose tissue without stimulating appetite or affecting blood sugar in the same way as growth hormone. Laboratory studies report increased fat oxidation in some models. The precise receptor interactions and signaling pathways remain incompletely characterized. Researchers have proposed that the peptide may influence fat mobilization through pathways distinct from the full hormone.
Research has examined whether the peptide affects fat mass independently of growth hormone's other actions. Early animal studies suggested reductions in body fat, but species differences and small sample sizes limit interpretation. Human studies have generally been short and have not consistently shown large effects. Some trials measured body composition, lipid profiles, and safety parameters, but the overall picture is one of suggestive yet inconclusive metabolic activity. Findings vary across study populations and protocols.
A central uncertainty is whether observed metabolic changes translate into meaningful clinical benefits. Study designs vary in dose, duration, and participant characteristics, making comparisons difficult. Independent replication is limited, and the field lacks consensus on optimal endpoints or treatment duration. Ongoing or future studies may clarify mechanism and effect size, but current evidence does not establish a clear therapeutic role. Researchers often call for larger, longer, and better-controlled trials, while questions remain about which patient groups might respond.
AOD-9604 is a synthetic peptide modeled on the C-terminal region of human growth hormone. It corresponds to residues 176-191 of the 191-amino-acid hGH sequence. The fragment is not the full hormone and lacks the receptor-binding region associated with growth and metabolic effects of hGH. Researchers developed it to isolate a specific portion of hGH for study. Its exact sequence and length are often stated in peptide catalogs and patents.
The peptide is frequently described as a growth hormone fragment, although it is chemically distinct from full-length hGH. AOD-9604 contains 16 amino acids and includes two cysteine residues that can form an intramolecular disulfide bond. In solution, this structural feature can influence folding, aggregation, and stability. Published descriptions sometimes call it hGH 176-191 or AOD9604, with spacing and capitalization varying. Such naming differences can complicate literature searches, database entries, and product verification.
Proposed mechanisms for AOD-9604 focus on fat cells. Laboratory studies suggest the peptide can increase lipolysis, the breakdown of stored fat, and reduce lipogenesis, the formation of new fat. Unlike full human growth hormone, it does not appear to stimulate substantial IGF-1 production in the studies reported so far. Some evidence points to beta-adrenergic signaling, but the precise receptor targets and downstream pathways remain unresolved. The fragment is not thought to act through the classical growth hormone receptor.
Clinical development of AOD-9604 included trials in people with obesity. Reports from early-phase and mid-phase studies described modest or inconsistent changes in body weight. A phase IIb program did not meet its primary endpoint, and the compound was not approved for medical use. Differences in formulation, delivery route, and participant characteristics may explain some of the variation. Later investigations explored whether the peptide might have effects in other tissues, including cartilage.
Follikuläres Schilddrüsenkarzinom (FTC) 10–30 % Bei diesem Karzinom ähnelt der Gewebeaufbau weitgehend der Struktur einer ausgereiften oder sich entwickelnden Schilddrüse. Die Krebszellen gehen von den Thyreozyten aus und bilden vorwiegend über die Blutbahn Absiedlungen (hämatogene Metastasierung) in Lunge, Skelett und Gehirn. Auf das follikuläre Karzinom entfallen 20–50 % aller Schilddrüsenkarzinome. In den USA ergab eine SEER-Analyse der Jahre 1988–2003 einen Anteil von 9,4 % aller bösartigen Schilddrüsenkarzinome. Es betrifft häufig Frauen im 4. und 5. Lebensjahrzehnt. Für follikuläre Karzinome der Schilddrüse ist eine immunhistochemisch nachweisbare Expression von Thyreoglobulin typisch. Mit einer tumorspezifischen 5-jahres-Sterblichkeit von 2,6 % ist die Prognose gut.
=== Undifferenzierte oder anaplastische Karzinome === Dieses Karzinom (etwa 5 % aller Fälle) zeigt in seiner Feinstruktur keine Ähnlichkeiten mehr mit dem ursprünglichen Schilddrüsengewebe und wird deshalb auch als undifferenziertes Karzinom bezeichnet. Es wächst aggressiv in das umliegende Gewebe ein und metastasiert sowohl lymphogen als auch hämatogen. Etwa 5–10 % der Schilddrüsenkarzinome entfallen auf diesen Typ. Selten entsteht es vor dem 60. Lebensjahr; eine Geschlechtspräferenz zeigt es nicht. Da bei diesem Tumortyp die undifferenzierten Karzinomzellen nicht mehr am Jodstoffwechsel teilnehmen, ist eine Radiojodtherapie nicht sinnvoll.
Das medulläre Schilddrüsenkarzinom (auch „C-Zell-Karzinom“) geht nicht von den Thyreozyten (den Jod-speichernden Schilddrüsenzellen) aus, sondern von den parafollikulären, Calcitonin-produzierenden Zellen (sogenannte C-Zellen), die aufgrund entwicklungsgeschichtlicher Zusammenhänge in der Schilddrüse liegen, aber in keinem Zusammenhang mit der eigentlichen Schilddrüsenfunktion (Thyreozyten) stehen. Etwa 5–10 % aller Schilddrüsenkarzinome zählen zu diesem Typ. Erstmals 1959 als eigene Entität neben den differenzierten und undifferenzierten Schilddrüsenkarzinomen beschrieben, tritt das medulläre Karzinom familiär (ca. 15 %) oder sporadisch (ca. 85 % der medullären Schilddrüsenkarzinome; Altersgipfel zw. 50.–60. Lebensjahr) auf. Bei dem familiären Typ unterscheidet man das familiäre Auftreten allein des medullären Schilddrüsenkarzinoms (FMTC) vom Syndrom der multiplen endokrinen Neoplasie Typ 2A und 2B. Ursache der familiären (d. h. erblichen) Form sind Mutationen im RET-Gen. Bei der Diagnose eines medullären Schilddrüsenkarzinoms sollte (nach vorheriger Aufklärung des Patienten und mit dessen Zustimmung) immer auch eine genetische Analyse erfolgen, da auch andere Familienangehörige den Gendefekt geerbt haben können. Falls weitere Familienangehörige ebenfalls die entsprechende RET-Mutation tragen, wird diesen im Abhängigkeit vom Typ der Mutation ggf. eine prophylaktische Schilddrüsenoperation (Thyreoidektomie) empfohlen. Der sensitivste Tumormarker des medullären Karzinomes ist das von den C-Zellen produzierte Calcitonin.
Sources: de.wikipedia.org
Bei erhöhtem Calcitonin-Spiegel wurde früher zur weiteren Differenzierung zwischen einer gutartigen Hyperplasie der C-Zellen und einem bösartigen Geschehen ein Pentagastrin-Test durchgeführt. Da der Pentagastrin-Test nicht mehr verfügbar ist, wird heute mit Calcium stimuliert oder es werden basale geschlechtsspezifische Grenzwerte benutzt, die zu gleichen Ergebnissen führen. In der Tumornachsorge dienen erhöhte Calcitonin-Werte im Blut als Indikator für ein Rezidiv. Da die C-Zellen nicht am Jodstoffwechsel teilnehmen, ist auch beim medullären Schilddrüsenkarzinom eine Radiojodtherapie nicht sinnvoll.
Sources: de.wikipedia.org
It is a synthetic peptide based on a C-terminal fragment of human growth hormone. It is commonly referred to as hGH fragment 176-191 and is studied for metabolic effects rather than growth effects.
No. It represents only a short portion of the hGH sequence and lacks the full hormone's structure. As a result, its biological activity and regulatory status differ from those of prescription hGH.
The exact peptide is not typically described as a circulating hormone; it is a synthetic construct based on a natural sequence. Fragments of hGH can exist in laboratory or metabolic contexts, but AOD-9604 itself is manufactured for research.
AOD-9604 is a synthetic peptide fragment of human growth hormone, corresponding to amino acids 176-191. It is studied for potential effects on fat metabolism, but it is not approved as a drug in most countries. Its exact mechanism remains under investigation.