A practical reference on anti-doping analysis: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-18. Anything still debated is marked as such rather than presented as settled.
AOD-9604 is prohibited in sport by the World Anti-Doping Agency under the peptide hormone class. Its presence in a sample can be detected through mass spectrometry-based methods, although the exact assay depends on the laboratory. In research settings, material is often supplied as a lyophilized powder for reconstitution. Buyers and researchers should note that products labeled AOD-9604 may vary in purity and actual peptide content. Analytical certificates and independent testing are common ways to verify identity, but no global harmonized standard exists for all commercial lots.
AOD-9604 is a synthetic peptide whose sequence is modeled on the C-terminal region of human growth hormone. Published descriptions commonly place it as a modified fragment corresponding to hGH amino acids 176–191, with a tyrosine residue added or retained at the N-terminus to support detection and handling. It is not intact growth hormone and lacks the full receptor-binding architecture of the parent protein. The molecule was developed as a research candidate for metabolic studies rather than as a replacement for growth hormone therapy. Its identity is defined by its amino acid sequence rather than by any single commercial preparation.
AOD-9604 drew attention in the 1990s and 2000s as a potential anti-obesity agent. Early work explored both injectable and oral routes, which is unusual for a peptide of this size. Animal studies reported changes in fat metabolism without the growth-promoting or insulin-like effects associated with full-length growth hormone. Subsequent human trials produced mixed or modest results, and the compound did not obtain regulatory approval for weight management in major markets. It remains known mainly through research literature, sports anti-doping listings, and non-approved supplement advertising.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Fragment analog of human growth hormone |
| Sequence basis | hGH 176–191 region | Modified C-terminal fragment |
| Common synonyms | AOD-9604; AOD9604; hGH fragment | Research and trade names vary |
| Regulatory status | Not approved as a drug | Prohibited in competitive sport |
| Research code | AOD9604 | Used in scientific and patent literature |
In laboratory settings, AOD-9604 is commonly supplied as a lyophilized powder and stored cold to limit degradation. Reconstituted solutions are typically kept refrigerated or frozen, depending on the buffer and concentration, and protected from repeated freeze-thaw cycles. Stability can be influenced by pH, temperature, and the presence of proteases. Purity is usually assessed by high-performance liquid chromatography and mass spectrometry. These practices support reproducibility, but they do not imply safety or efficacy for any human use.
Regulatory status: AOD-9604 is not approved as a therapeutic drug in the United States, European Union, or other major markets. It is listed by the World Anti-Doping Agency as a prohibited substance in sport, specifically under growth hormone fragments. Many jurisdictions restrict its sale for human consumption. Products marketed online may not meet pharmaceutical quality standards. The legal status varies by country and often depends on whether the material is presented as a research chemical, supplement, or drug.
Detection and characterization of AOD-9604 in research and anti-doping settings typically rely on mass spectrometry coupled with liquid chromatography. These methods can identify the peptide by its mass and fragmentation pattern. Immunoassays may also be used in some screening contexts, but they can cross-react with related peptides. Because the molecule is small and may be present at low concentrations, sample preparation and method validation are important. Confirmatory analysis usually requires comparison with a certified reference standard.
Identity and purity are usually assessed with reversed-phase high-performance liquid chromatography and mass spectrometry. Reversed-phase HPLC separates the peptide from related impurities and can estimate purity by ultraviolet absorbance, while mass spectrometry confirms the molecular mass and detects modifications. Peptide mapping, amino acid analysis, and disulfide mapping may be used when the sequence or disulfide arrangement must be verified. Because AOD9604 contains cysteine residues, oxidation and disulfide isomers are possible quality concerns in synthetic batches.
Quality varies among research-grade suppliers, so certificates of analysis and independent testing are important for verification. A typical certificate reports purity by HPLC, identity by mass spectrometry, appearance, and sometimes residual solvents or water content. AOD9604 is often sold as a research chemical not intended for human consumption, and labels can be inaccurate. Common misconceptions include treating the peptide as a form of growth hormone, assuming supplement status, or expecting approved-drug quality from unregulated products.
AOD9604 is commonly supplied as a white to off-white lyophilized powder. The powder is typically stored at -20 °C or below, protected from light and moisture, because peptides can degrade through oxidation, hydrolysis, or aggregation. If it is reconstituted for laboratory use, an appropriate aqueous buffer or solvent is chosen, and the solution is kept cold and handled to avoid repeated freeze-thaw cycles. These practices support stability but do not imply suitability for human use.
AOD-9604 is a synthetic peptide modeled on the C-terminal region of human growth hormone. It is often described as hGH fragment 176-191. Research interest arose because it was designed to isolate possible effects on fat metabolism from other actions of growth hormone. It is not a full growth hormone molecule. Its development history includes early laboratory and animal studies followed by human trials. The peptide has been examined in laboratory, animal, and limited human studies.
The compound has been studied as a potential treatment for obesity and related metabolic conditions. Published trials have examined changes in body weight, fat mass, and safety markers over limited durations. Results have been mixed or modest, and no large-scale outcome trials are established. Regulatory agencies in several countries have not approved it as a therapeutic drug. Some commercial products have been marketed outside regulated pharmaceutical channels, which raises questions about quality and claims.
AOD-9604 is typically supplied as a lyophilized white to off-white powder. In this form, it is relatively stable when kept cool, dry, and protected from light. Common storage recommendations place it at −20 °C or below for long-term retention. Reconstituted solutions are less stable and are often kept at 2–8 °C for short periods. Freeze-thaw cycles should be minimized because they can promote aggregation or loss of peptide content. Vials are usually sealed under inert gas to reduce oxidation.
Identity and purity are commonly checked with reversed-phase high-performance liquid chromatography and mass spectrometry. RP-HPLC separates the peptide from related impurities and can estimate purity by peak area. Mass spectrometry confirms molecular mass and helps detect sequence variants or truncations. Some laboratories use amino acid analysis or peptide mapping for additional characterization. No single method proves biological activity; these techniques establish chemical identity and purity only. They also require suitable reference standards for confident comparison.
Commercial AOD-9604 may vary in purity, counterion content, and residual moisture. Certificates of analysis often report HPLC purity, mass confirmation, and appearance, but testing methods differ between suppliers. Independent verification is sometimes used because labeled content may not match actual peptide amount. Stability under different pH and temperature conditions is not fully standardized across studies. Researchers generally treat lyophilized material as the reference form for weighing and reconstitution. Moisture content can affect accurate mass measurement.
The drugs used in the 2026 Enhanced Games had to be on the US Food and Drug Administration list of legally approved substances, which includes muscle building substances like testosterone and anabolic steroids; substances that boost endurance, like human growth hormone and Erythropoietin (EPO); stimulants, like Adderall, that improve focus; and metabolic drugs, like meldonium, which alter how the body burns fat. Enhanced made drug recommendations, but each athlete was free to choose what they took. According to the Enhanced Games, 91% of the athletes who took performance-enhancing substances used testosterone or testosterone esters; 79% used human growth hormone; 62% used stimulants such as Adderall; 50% used metabolic modulators; 41% used Erythropoietin; and 29% used anabolic steroids. According to strongman Hafþór Júlíus Björnsson, he took testosterone, nandrolone decanoate, oxymetholone and fluoxymesterone. To compete, he said he had to stop taking methandrostenolone, trenbolone and boldenone undecylenate. Cody Miller said he took, in the eight-week period leading up to the competition, testosterone, human growth hormone and oxandrolone.
A number of AlphaFold clones have also been published, mostly with permissive license terms. Clones for AlphaFold3 include ByteDance's Protenix (Apache 2.0 License), AlQuraishi Laboratory's OpenFold-3 (MIT license), and Boltz-1/2 (MIT license). There are also clones for older versions, though they became less relevant with the open-source release of AlphaFold 1 and 2 source codes. Still relevant are models, both open- and closed-source, that include modifications to the AlphaFold architecture. For AlphaFold 2, a notable example is ESMFold from Meta, which replaces the multiple sequence alignment with the latent space of a protein language model. Open-source tools that complement AlphaFold have also been made. One well-cited example is ColabFold, which uses MMseqs2 instead of HHblits to speed up the sequence search, allowing the AlphaFold pipelines to run quickly on Google Colab.
(CH3)2CO → CH3 + CH3CO The latter process is relevant to the atmospheric chemistry of acetone. Acetone can then be metabolized either by CYP2E1 via methylglyoxal to D-lactate and pyruvate, and ultimately glucose/energy, or by a different pathway via propylene glycol to pyruvate, lactate, acetate (usable for energy) and propionaldehyde. About a third of the world's acetone is used as a solvent, and a quarter is consumed as acetone cyanohydrin, a precursor to methyl methacrylate. Acetone is used to synthesize methyl methacrylate. It begins with the initial conversion of acetone to acetone cyanohydrin via reaction with hydrogen cyanide (HCN): (CH3)2CO + HCN → (CH3)2C(OH)CN In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified: (CH3)2C(OH)CN + CH3OH → CH2C(CH3)CO2CH3 + NH3 The third major use of acetone (about 20%) is synthesizing bisphenol A. Bisphenol A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins. The synthesis involves the condensation of acetone with phenol:
Most commonly 2,5-diketopiperazines are generated by cyclisation of dipeptides. In addition to the many methods of peptide synthesis, the Ugi reaction can be applied. Dipeptides with an ester terminus spontaneously cyclize often. Racemization can be problematic. The Ugi reaction using an isonitrile, amino acid, aldehyde and amine, can produce a dipeptide in equally high yield and optical purity, to that formed by standard peptide couplings. Commonly, an isonitrile is chosen to give a labile terminal amide to enable cyclization. For example, the direct 2,5-DKP ring formation via such an activated leaving group using the stable, easily accessible and versatile convertible isonitrile 1-isocyano-2-(2,2-dimethoxyethyl)-benzene 4 gave a one-pot synthesis of N-substituted 2,5-diketopiperazine's 7.
In organic chemistry, an active ester is an ester functional group that is highly susceptible toward nucleophilic attack. Activation can be imparted by modifications of the acyl or the alkoxy components of a normal ester, say ethyl acetate. Typical modifications call for electronegative substituents. Active esters are employed in both synthetic and biological chemistry. Active esters are mainly used as acylating agents. They undergo the same reactions as their unactivated analogues but do so more rapidly. They are prone to hydrolysis, for example. Of great interest is the enhanced reactivity of active esters toward amines to give amides. Active esters are prominent in biochemistry. Glutamine synthetase is an enzyme that forms an active ester from the terminal carboxylate of glutamic acid. This activation, imparted by phosphorylation, facilitates the conversion of the carboxylate to an amide called glutamine.
Sources: en.wikipedia.org
Although they are classically thought of working only together, GPCRs may signal through G-protein-independent mechanisms, and heterotrimeric G-proteins may play functional roles independent of GPCRs. GPCRs may signal independently through many proteins already mentioned for their roles in G-protein-dependent signaling such as β-arrs, GRKs, and Srcs. Such signaling has been shown to be physiologically relevant, for example, β-arrestin signaling mediated by the chemokine receptor CXCR3 was necessary for full efficacy chemotaxis of activated T cells. In addition, further scaffolding proteins involved in subcellular localization of GPCRs (e.g., PDZ-domain-containing proteins) may also act as signal transducers. Most often the effector is a member of the MAPK family.
Solid-liquid extraction based ambient ionization is based on the use of a charged spray, for example electrospray to create a liquid film on the sample surface. Molecules on the surface are extracted into the solvent. The action of the primary droplets hitting the surface produces secondary droplets that are the source of ions for the mass spectrometer. Desorption electrospray ionization (DESI) is one of the original ambient ionization sources and uses an electrospray source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer. Desorption atmospheric pressure photoionization (DAPPI) is a solid-liquid extraction ambient ionization method that enables the direct analysis of samples deposited on surfaces by means of a jet of hot solvent vapour and ultraviolet light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer.
F-ATPase gene linkage and gene order are widely conserved across ancient prokaryote lineages, implying that this system already existed at a date before the last universal common ancestor, the LUCA. Nick Lane: The Vital Question: Energy, Evolution, and the Origins of Complex Life, Ww Norton, 2015-07-20, ISBN 978-0393088816 (Link points to Figure 10 showing model of ATP synthase) Boris A. Feniouk: "ATP synthase — a splendid molecular machine" Well illustrated ATP synthase lecture Archived 2008-12-02 at the Wayback Machine by Antony Crofts of the University of Illinois at Urbana–Champaign. Proton and Sodium translocating F-type, V-type and A-type ATPases in OPM database The Nobel Prize in Chemistry 1997 to Paul D. Boyer and John E. Walker for the enzymatic mechanism of synthesis of ATP; and to Jens C. Skou, for discovery of an ion-transporting enzyme, Na+, K+-ATPase. Harvard Multimedia Production Site — Videos – ATP synthesis animation David Goodsell: "ATP Synthase- Molecule of the Month" Archived 2015-09-05 at the Wayback Machine
Most commonly 2,5-diketopiperazines are generated by cyclisation of dipeptides. In addition to the many methods of peptide synthesis, the Ugi reaction can be applied. Dipeptides with an ester terminus spontaneously cyclize often. Racemization can be problematic. The Ugi reaction using an isonitrile, amino acid, aldehyde and amine, can produce a dipeptide in equally high yield and optical purity, to that formed by standard peptide couplings. Commonly, an isonitrile is chosen to give a labile terminal amide to enable cyclization. For example, the direct 2,5-DKP ring formation via such an activated leaving group using the stable, easily accessible and versatile convertible isonitrile 1-isocyano-2-(2,2-dimethoxyethyl)-benzene 4 gave a one-pot synthesis of N-substituted 2,5-diketopiperazine's 7.
Over the years, multiple synthesizers have been developed to assist with automated synthesis, including the Chemspeed Accelerator (SLT106, SLT II, ASW2000, SwingSLT, Autoplant A100, and SLT100), the Symyx system, and Freeslate ScPPR. Recently, researchers have investigated the optimization of these methods for controlled/living radical polymerization (CLRP), which faces issues with oxygen intolerance. This research has led to the development of oxygen-tolerant CLRP, including with the use of enzyme degassing of RAFT (Enz-RAFT), atom-transfer radical (ATRP) that possesses tolerance to air, and photoinduced electron/energy transfer–RAFT (PET–RAFT) polymerization. Through the use of liquid-handling robots, Tamasi et al. demonstrated the use of automated synthesis with executing multi-step procedures, enabling the reactions to investigate more elaborate schemes, such as with scale and complexity. Lee Cronin and his team have developed a modular synthesis machine called the chemputer which uses a dedicated programming language for chemical synthesis.
Sources: en.wikipedia.org
AOD9604 is an orally active, lipolytic 16-amino acid peptide fragment of human growth hormone and derivative of the C-terminal domain of human growth hormone (HGH). It consists of HGH residues 176–191, with a tyrosine in place of the phenylalanine at the N-terminal end. Initial human trials showed that it retains the lipolytic properties of human growth hormone without stimulating IGF-1 production. However, later studies failed to demonstrate a sufficient lipolytic effect. Its development was terminated in 2007. Despite its limited efficacy, AOD9604 is still banned in athletes and tested for in competition. AOD9604 appears to enhance lipolysis in mice by upregulating beta-3 adrenergic receptors. Beta-3 adrenergic receptor knockout mice are unresponsive to the lipolytic effects of AOD9604. In a 12 week randomised clinical trial, subjects receiving AOD9604 lost, on average, 1.8 kg more than those receiving placebo. Development of AOD9604 was halted following poor efficacy in a later 24 week trial.
Absolute bioavailability compares the bioavailability of the active drug in systemic circulation following non-intravenous administration (i.e., after oral, buccal, ocular, nasal, rectal, transdermal, subcutaneous, or sublingual administration), with the bioavailability of the same drug following intravenous administration. It is the fraction of exposure to a drug (AUC) through non-intravenous administration compared with the corresponding intravenous administration of the same drug. The comparison must be dose normalized (e.g., account for different doses or varying weights of the subjects); consequently, the amount absorbed is corrected by dividing the corresponding dose administered. In pharmacology, in order to determine absolute bioavailability of a drug, a pharmacokinetic study must be done to obtain a plasma drug concentration vs time plot for the drug after both intravenous (iv) and extravascular (non-intravenous, i.e., oral) administration. The absolute bioavailability is the dose-corrected area under curve (AUC) non-intravenous divided by AUC intravenous. The formula for calculating the absolute bioavailability, F, of a drug administered orally (po) is given below (where D is dose administered).
From 2002 to 2004, Pinhasov carried out postdoctoral research at Johnson & Johnson Pharmaceutical Research and Development (Spring House, Pennsylvania, United States), where under the guidance of Dr. Douglas Brenneman he was engaged in the development of drugs for the treatment of neurodegenerative diseases. In 2005, Pinhasov joined the Department of Molecular Biology at Ariel University (formerly the College of Judea and Samaria) as an assistant professor. He was Head of the department from 2008 to 2014. In 2014, Pinhasov was appointed Vice-President and Dean of Research & Development at Ariel University, holding this position until 2020. In 2020 the Senate of Ariel University elected Professor Pinhasov as the Rector of Ariel University, succeeding Professor Michael Zinigrad, who held this office for 12 years. In September 2023, in recognition of his contribution to academic ties between Israel and Kazakhstan, the Senate of Astana Medical University (AMU) awarded Prof. Albert Pinhasov the title of honorary professor.
n RCHNHC(O)OC(O) → [N(H)CH(R)CO)]n + n CO2 Poly-L-lysine has been prepared from N-carbobenzyloxy-α-N-carboxy-L-lysine anhydride, followed by deprotection with phosphonium iodide. Peptide synthesis from NCAs does not require protection of the amino acid functional groups. N-Substituted NCAs, such as sulfenamide derivatives have also been examined. The ring-opening polymerization of NCAs is catalyzed by metal catalysts. The polymerization of NCA’s have been considered as a prebiotic route to polypeptides. NCAs can also be used to form amides and lactams by reaction of carboxylic acids and isocyanates. Dakin–West reaction Glycine N-carboxyanhydride, the parent NCA
Sources: en.wikipedia.org
No. It is a synthetic peptide fragment modeled on part of human growth hormone, not the full hormone. It does not contain the complete sequence or receptor-binding regions of hGH.
It was investigated in clinical trials for obesity, but it did not receive approval for that use in major markets. Results were generally modest or mixed, and it remains an experimental compound.
WADA lists it as a prohibited peptide hormone. Its use can be detected by laboratory methods, and athletes are subject to sanctions if it is found in samples.
Yes, the World Anti-Doping Agency classifies AOD-9604 as a prohibited peptide hormone and related substance. Its use by athletes is banned under the relevant anti-doping code.