hGH fragment is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-05-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
Analytical characterization of AOD-9604 typically employs reversed-phase high-performance liquid chromatography (RP-HPLC) to assess purity and identity. Mass spectrometry provides confirmation of molecular mass, while amino acid analysis can verify composition. These methods are standard for peptide research chemicals. Because the peptide lacks a distinct chromophore, detection often relies on ultraviolet absorbance at 214 nm or mass spectrometric response. Laboratories may also use capillary electrophoresis for separation. For example, size-exclusion chromatography can detect aggregates.
Stability of AOD-9604 depends on storage conditions. Lyophilized powder is generally more stable than reconstituted solution. Recommended storage is typically at -20°C or lower, protected from light and moisture. Repeated freeze-thaw cycles can cause aggregation or degradation. In solution, the peptide may be susceptible to hydrolysis or oxidation, so aliquoting and cold storage are common practices. Researchers often add stabilizers such as mannitol or trehalose during lyophilization to improve shelf life.
AOD-9604 is a synthetic peptide that corresponds to a short section of human growth hormone. It is commonly identified as hGH fragment 176-191 because its sequence matches residues at the C-terminal end of the hormone. The molecule contains sixteen amino acids and is made by solid-phase peptide synthesis. Researchers study it for metabolic effects rather than for the growth-promoting actions associated with full human growth hormone. Its small size distinguishes it from the complete 191-amino-acid hormone.
Several names appear in scientific and commercial settings. AOD9604 and AOD-9604 are development codes used interchangeably, while hGH fragment 176-191 describes the same region. The peptide includes a disulfide bond between two cysteine residues, which helps shape its three-dimensional structure. Different suppliers may provide acetate or other salt forms, and purity can vary. These differences matter because analytical tests and biological assays can respond to the specific form being studied.
Early interest in AOD-9604 centered on whether a fragment of human growth hormone could influence fat metabolism without the broader effects of the full hormone. Cell and animal studies reported changes in fat storage and breakdown. Human trials followed, but the results were not strong enough to secure regulatory approval. The compound remains available for laboratory research, and its clinical potential is still described as uncertain. Studies continue to examine its activity and safety profile.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Soluble in water | Also soluble in aqueous buffers |
| Storage temperature | -20°C or below | Protect from light and moisture |
| Analytical method | RP-HPLC | Purity and identity assessment |
| Mass confirmation | Mass spectrometry | Verifies molecular mass |
AOD-9604 has been investigated primarily as a potential treatment for obesity and related metabolic conditions. Early laboratory work examined its effects on fat cells, and later studies moved into animal models and human clinical trials. Some trials reportedly reached Phase II, but the program did not lead to an approved medicine. Published summaries often note that weight-loss results were modest or inconsistent. The full trial data are not all publicly available in detail.
Regulatory treatment of AOD-9604 has varied. In sports anti-doping, the peptide became widely discussed during a 2013 investigation into an Australian professional sports club. Authorities at the time debated whether it fell under prohibitions on growth hormone and related substances. Later clarifications and updated lists have addressed the compound in different ways. Anyone seeking current status should consult the latest applicable rules, and commercial supply for human use is not authorized in major markets.
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.
Regulatory status varies by country. In the United States, AOD-9604 is not approved as a prescription drug. It is sometimes sold as a research chemical or dietary supplement, though such marketing may fall outside legal frameworks. The World Anti-Doping Agency prohibits its use in sport. Researchers must obtain it through legitimate suppliers and follow institutional rules. Its legal classification continues to evolve as authorities increasingly assess peptide products more broadly.
AOD-9604 is listed as a prohibited substance in sport by the World Anti-Doping Agency. It falls under the peptide hormones, growth factors, related substances, and mimetics class on the prohibited list. Anti-doping organizations treat its presence in an athlete's sample as an adverse finding unless a therapeutic use exemption applies. The prohibition reflects concerns about performance enhancement in competitive settings and the difficulty of distinguishing exogenous peptide use from endogenous hormone fragments.
Detection of AOD-9604 in biological samples relies on analytical techniques capable of distinguishing a small synthetic peptide from related endogenous sequences. Liquid chromatography coupled with tandem mass spectrometry is commonly used for confirmatory analysis. Sample preparation may involve immunoaffinity enrichment or solid-phase extraction to concentrate the peptide. Because the molecule is small and may be present at low concentrations, assay sensitivity and specificity are ongoing analytical challenges. Laboratories also validate methods against reference materials when available.
Regulatory interest in AOD-9604 increased after high-profile anti-doping cases involving peptide products. In some cases, the substance was supplied under alternative names or in compounded preparations, complicating traceability. Sports tribunals and anti-doping panels have discussed whether the peptide was explicitly banned at the time of use, leading to clarifications by the World Anti-Doping Agency. For consumers and researchers, the legal status can vary by jurisdiction, and products marketed as research chemicals may lack independent quality verification.
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.
Researchers have studied the fragment in cell and animal models to understand its metabolic actions. Some experiments report effects on fat breakdown and fat storage pathways, but the underlying mechanism remains incompletely defined. AOD-9604 does not appear to stimulate the same broad growth hormone receptor signaling as full-length hGH. Whether its observed activities arise from direct receptor interactions or downstream metabolic changes is an open question. Results from different assays are not always consistent.
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.
=== Binding of SSRIs to SERT protein === The molecular basis for SSRIs function, including their binding mode and molecular mechanism of 5-HT re-uptake inhibition in SERT, is not fully understood and is a matter of debate. Such information is very important for the understanding of essential aspects of the drugs action, ranging from selectivity profile to therapeutic efficacy and the development of new and improved drugs that target the human SERT. The three-dimensional (3D) structure of SERT is not known and has been the main obstacle for elucidation of the structural mechanism of the human SERT. Update: X-ray crystallography data is available as of 2017 it seems (https://www.rcsb.org/structure/6AWO)... Comparative molecular modeling have been used in research to create structural models of human SERT in complex with its ligand but has not given good results because of low phylogenetic and functional similarity between human SERT and available template proteins. However the 3D structure of some bacterial homologous transporters like the leucine transporter (LeuT) is known. The human SERT, NET and DAT are all members of the neurotransmitter:sodium symporter (NSS) protein family. SERT contains approximately 630 amino acids that are predicted to form 12 transmembrane alpha-helixes (TMs) which are connected with intra- and extracellular loops (ILs and ELs).
Cellular membrane disruption Chemical reaction with downstream effects Interaction with enzyme proteins Interaction with structural proteins Interaction with carrier proteins Interaction with ion channels Ligand binding to receptors: Hormone receptors Neuromodulator receptors Neurotransmitter receptors General anesthetics were once thought to work by disordering the neural membranes, thereby altering the Na+ influx. Antacids and chelating agents combine chemically in the body. Enzyme-substrate binding is a way to alter the production or metabolism of key endogenous chemicals, for example aspirin irreversibly inhibits the enzyme prostaglandin synthetase (cyclooxygenase) thereby preventing inflammatory response. Colchicine, a drug for gout, interferes with the function of the structural protein tubulin, while digitalis, a drug still used in heart failure, inhibits the activity of the carrier molecule, Na-K-ATPase pump. The widest class of drugs act as ligands that bind to receptors that determine cellular effects. Upon drug binding, receptors can elicit their normal action (agonist), blocked action (antagonist), or even action opposite to normal (inverse agonist). In principle, a pharmacologist would aim for a target plasma concentration of the drug for a desired level of response. In reality, there are many factors affecting this goal. Pharmacokinetic factors determine peak concentrations, and concentrations cannot be maintained with absolute consistency because of metabolic breakdown and excretory clearance.
=== Addiction remission === The term fen-phen was created in 1994 when Pietr Hitzig and Richard B. Rothman reported that this combination could presumptively remit alcohol and cocaine craving. The authors suggested that other combined dopamine and serotonin agonists or precursors might share this therapeutic potential. Subsequent experiments in rats supported these preliminary reports. In 2006 it was confirmed that the combination of phentermine and the serotonin precursor 5-hydroxytryptophan (5-HTP), in place of fenfluramine, significantly decreased alcohol withdrawal seizures in rats. Intramural National Institutes of Health (NIH) double-blind protocols to demonstrate the efficacy of fen-phen in alcohol and cocaine addiction were designed, but never performed.
Sources: en.wikipedia.org
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in them having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen (and in the case of lithium, nitrogen). Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in salts and never as the free elements. Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.
British importer BBH Spirits began to import Hill's Absinth from the Czech Republic in the 1990s, as the UK had never formally banned it, and this sparked a modern resurgence in its popularity. It began to reappear during a revival in the 1990s in countries where it was never banned. Forms of absinthe available during that time consisted almost exclusively of Czech, Spanish, and Portuguese brands that were of recent origin, typically consisting of Bohemian-style products. Connoisseurs considered these of inferior quality and not representative of the 19th-century spirit. In 2000, La Fée Absinthe became the first commercial absinthe distilled and bottled in France since the 1914 ban, but it is now one of dozens of brands that are produced and sold within France. In the Netherlands, the restrictions were challenged by Amsterdam wine seller Menno Boorsma in July 2004, thus confirming the legality of absinthe once again. Similarly, Belgium lifted its long-standing ban on 1 January 2005 citing a conflict with the adopted food and beverage regulations of the single European Market. In Switzerland, the constitutional ban was repealed in 2000 during an overhaul of the national constitution although the prohibition was written into ordinary law instead. That law was later repealed, and absinthe was made legal on March 1, 2005. The drink was never officially banned in Spain although it began to fall out of favour in the 1940s and almost vanished into obscurity. Catalonia has seen a significant resurgence since 2007 when one producer established operations there.
== Interactions == Extracellular interaction with a tripartite receptor composed of gp130, WSX1, and CNTFR, as well as interaction with the formyl peptide receptor 2 (formylpeptide-like-1 receptor) have been published. Intracellular interaction with BAX, tBID, IGFBP3, and TRIM11 may also be required for the effects of humanin.
Sources: en.wikipedia.org
Reversed-phase HPLC is used to assess purity, and mass spectrometry confirms molecular mass. Amino acid analysis can verify composition. These methods are standard for peptide characterization.
Lyophilized powder should be stored at -20°C or lower, protected from light and moisture. Reconstituted solutions are less stable and should be aliquoted to avoid freeze-thaw cycles. Always follow supplier instructions.
Variability in purity, counterion content, and residual solvents is possible. Independent testing and certificates of analysis help verify quality. Microbial contamination can occur if handling is not sterile.
AOD-9604 is a synthetic peptide fragment of human growth hormone. It corresponds to the C-terminal region known as hGH 176-191 and is studied for metabolic effects. It is not an approved therapeutic drug.