This is a working overview of synthetic peptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-01 and is reviewed periodically as new material appears.
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.
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.
Research interest in AOD-9604 often focuses on whether it can influence lipid metabolism without the growth-promoting or glucose-related effects of full-length hGH. This question remains unresolved, and findings depend on model, dose, and measurement method. Some reviews treat the peptide as a historical obesity candidate rather than an active therapeutic. Others cite it in discussions of peptide fragments, metabolic signaling, and performance-enhancing substances. Clear conclusions are limited by the small number of rigorous, independent human studies.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized form; may appear as cake |
| Solubility class | Water-soluble | Often reconstituted in aqueous buffer |
| Typical storage temperature | −20 °C or below | Protect from light and moisture |
| Typical analytical method | RP-HPLC and mass spectrometry | Used for purity and identity |
| Common synonyms | AOD-9604; AOD9604; hGH fragment 176-191 | Research name and fragment description |
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.
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.
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.
Quality control for AOD-9604 involves verifying identity, purity, and concentration. Suppliers may provide a certificate of analysis listing HPLC purity and mass spectrometry data. Independent verification is advised because peptide products can vary in quality. Researchers should check for counterions, residual solvents, and microbial contamination. Proper documentation supports reproducibility and safety in laboratory studies. When sourcing, institutions often require third-party testing and detailed chain-of-custody records. These steps help ensure that experimental results are attributable to the peptide rather than impurities.
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.
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 structure corresponds to a C-terminal segment of human growth hormone. It is often described as hGH fragment 176-191, a 16-amino-acid sequence. The peptide was designed to isolate a region of hGH associated with fat metabolism while avoiding the full hormone's growth-promoting actions. Laboratory and commercial materials typically present it as a lyophilized powder for research use. Its identity is defined by amino acid sequence, not by a single brand.
== External links == vcclab.org. Overview of the many logP and other physical property calculators available commercially and on-line. XLOGP3, a simple LogP estimator used by PubChem (release 2021.05.07)
. The ratio of the stepwise stability constants can be calculated on this basis, but experimental ratios are not exactly the same because ΔH⊖ is not necessarily the same for each step. Exceptions to this rule are discussed below, in #chelate effect and #Geometrical factors.
==== siRNA delivery ==== Short interfering RNA (siRNA) is a powerful new tool that can interfere with and silence the expression of specific disease gene. To improve cellular uptake of siRNA, CPP strategies have been applied to facilitate the delivery of siRNA into cells through either covalent or non-covalent linkages. In one study, siRNA is covalently linked to transportation and penetration by disulfide-linkage at 5'-end of the sense strands of siRNA to target luciferase or eGFP mRNA reporters. In another study, TAT-siRNA conjugate through a stable thiomaleimide linkage at 3'-end of siRNA was delivered into HeLa cells for eGFP gene silencing. However, non-covalent strategies appear to be better for siRNA delivery with a more significant biological response. In one study, MPG/siRNA complexes formed through stable non-covalent strategy showed successful introduction of siRNA into cultured cells and induced robust regulation of target mRNA. Furthermore, MPG/siRNA complexes have also been applied for delivery of siRNA in vivo into mouse blastocytes for gene regulation. MPG forms stable complexes with siRNA with a low degradation rate and can be easily functionalized for specific targeting, which are major advantages compared with the covalent CPP technology.
== In popular culture == In the episode of House, "Skin Deep", opioid antagonist drugs were administered in order to completely remove the patient's heroin induced addiction/withdrawal symptoms (during an induced coma in order to relieve the extreme pain of their use), so that an accurate diagnosis of paraneoplastic syndrome caused by cancer was differentiated. In an episode of Royal Pains, a character dangerously tries to undergo a procedure (and go under anaesthesia) in his own home. In an episode of Hannibal, Dr.Lecter administers Naloxone to Jack Crawford's wife after she tries to commit suicide by overdosing on morphine.
Sources: en.wikipedia.org
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== June 23, 1915 (Wednesday) == First Battle of the Isonzo — Italy launched its first major military campaign in World War I with an army of 225,000 under command of Luigi Cadorna attacking Austro-Hungarian defense positions above the Isonzo River (now Soča) in the Alps. Battle of Bukoba — British colonial troops captured the German fort in Bukoba, German East Africa and destroyed the wireless station. Two magnitude 6.3 earthquakes struck within an hour of each other in the Imperial Valley, California. Six deaths were reported in Mexicali, Baja California, Mexico and damage costs were estimated at $900,000. German submarine SM U-40 was torpedoed and sunk in the North Sea by Royal Navy submarine HMS C24 with the loss of 38 of her 41 crew. The Royal Flying Corps decreed all aircraft with covered fuselages were to use the tricolor roundel, previously used on just the wings, on fuselage sides. Born: Aaron Robinson, American baseball player, catcher for the New York Yankees, Chicago White Sox, Detroit Tigers and Boston Red Sox from 1943 to 1951; in Lancaster, South Carolina, United States (d. 1966) Died: Ellen Hardin Walworth, 82, American historian, founder of the Daughters of the American Revolution (b. 1832)
tetramer A molecular aggregate consisting of four subunits. The term is often used to refer to protein complexes composed of four proteins, e.g. haemoglobin, or to individual proteins composed of four polypeptides. Compare monomer, dimer, and trimer.
Detection of several target analytes is possible by the spatial arrangement of different SWCNT sensors in arrays or by hyperspectral detection based on monochiral SWCNT sensors that emit at different emission wavelengths. For fluorescence applications, however, optical filters to distinguish between excitation and emission and a NIR-sensitive detector must be used. Standard silicon detectors can also be used if monochiral SWCNTs (extractable by special purification processes) emitting closer to the visible range (800 – 900 nm) are used. In order to avoid susceptibility of optical sensors to fluctuating ambient light, internal references such as SWCNTs that are modified to be non-responsive or stable NIR emitters can be used. An alternative is to measure fluorescence lifetimes instead of fluorescence intensities. Overall, SWCNTs therefore have great potential as building blocks for various biosensors. To render SWCNTs suitable for biosensing, their surface needs to be modified to ensure colloidal stability and provide a handle for biological recognition. Therefore, biosensing and surface modifications (functionalization) are closely related. Potential future applications include biomedical and environmental applications such as monitoring plant health in agriculture, standoff process control in bioreactors, research/diagnostics of neuronal communication and numerous diseases such as coagulation disorders, diabetes, cancer, microbial and viral infections, testing the efficacy of pharmaceuticals or infection monitoring using smart implants.
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Sources: en.wikipedia.org
Lyophilized powder is commonly stored at −20 °C or below, protected from light and moisture. Reconstituted solutions are typically kept refrigerated and used within a limited period.
Reversed-phase HPLC and mass spectrometry are standard checks. They confirm peptide purity and molecular mass, but they do not by themselves demonstrate biological activity.
Synthesis, purification, and handling conditions can differ, leading to variations in purity and salt content. Certificates of analysis help, but independent testing is often needed for verification.
No major medicines regulator appears to have approved AOD-9604 for human therapeutic use. It has been studied in clinical trials, but those programs did not result in a marketed drug.