metabolic research raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-23 and is reviewed periodically as new material appears.
Clinical development of AOD9604 included trials in people with obesity, but the results did not lead to approval as a prescription medicine in major markets. Interest later shifted to research settings and to unapproved products marketed for body composition. Regulatory agencies have questioned whether the peptide qualifies as a dietary ingredient, and some have issued warnings about its presence in supplements. Long-term human safety data are limited, and questions about efficacy, dosing, and target populations remain unresolved.
AOD9604 is a synthetic peptide modeled on the C-terminal region of human growth hormone. It corresponds to a short sequence near the end of the 191-amino-acid hormone, often described as residues 176–191 or a related fragment. Researchers designed it to separate metabolic effects from the growth-promoting actions of full-length growth hormone. Early work in the 1990s explored it as a candidate for weight and lipid disorders. It is not a naturally circulating hormone fragment produced in large amounts.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Derived from C-terminal region of human growth hormone |
| Approximate molecular mass | About 1.8 kDa | Varies with sequence length and counterions |
| Confirmed receptor target | None established | No confirmed growth hormone receptor agonism |
| Reported in vitro activity | Lipolysis stimulation and lipogenesis inhibition | Observed mainly in adipocyte models; human relevance uncertain |
| Regulatory status | Not approved as a drug in major markets | May be treated differently across jurisdictions; not a recognized dietary ingredient in some countries |
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.
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.
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.
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.
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.
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.
In selected reaction monitoring, the first analyzer allows only a single mass through and the second analyzer monitors for multiple user-defined fragment ions over longer dwell-times than could be achieved in a full scan. This increases sensitivity. In product ion scans, the first mass analyzer is fixed to select a particular precursor ion ("parent"), while the second is scanned to find all the fragments ("products", or "daughter ions") to which it can be fragmented in the collision cell. In precursor ion scans, the second mass analyzer is fixed to select a particular fragment ion ("daughter"), while the first is scanned to find all possible precursor ions that could give rise to this fragment. In neutral loss scans, the two mass analyzers are scanned in parallel, but separated by the mass of a molecular subunit of interest to the analyst. Ions are detected if they lose that fixed mass during fragmentation. This can be used to look for any chemical that is capable of losing a particular neutral group, for example a sugar residue. Together, neutral loss and precursor ion scans can be used to hunt for chemicals with particular motifs. Another type of tandem mass spectrometry used for radiocarbon dating is accelerator mass spectrometry, which uses very high voltages, usually in the mega-volt range, to accelerate negative ions into a type of tandem mass spectrometer. The METLIN Metabolite and Chemical Entity Database is the largest repository of experimental tandem mass spectrometry data acquired from standards.
== External links == "Melanocortin Receptors: MC4". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2008-12-05. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
== History == The deficiency was the first metabolic myopathy to be recognized when the physician Brian McArdle described the first case in a 30-year-old man who always experienced pain and weakness after exercise. McArdle noticed this patient's cramps were electrically silent and his venous lactate levels failed to increase upon ischemic exercise. (The ischemic exercise consists of the patient squeezing a hand dynamometer at maximal strength for a specific period, usually a minute, with a blood pressure cuff, which is placed on the upper arm and set at 250 mmHg, blocking blood flow to the exercising arm.) Notably, this is the same phenomenon that occurs when muscle is poisoned in vitro by iodoacetate, which inhibits the breakdown of glycogen into glucose and prevents the formation of lactate; as well as produces an electronically silent muscle contracture. Knowing what occurs to muscle poisoned by iodoacetate, helped McArdle speculate that a glycogenolytic block might be occurring when he first described the disease. McArdle accurately concluded that the patient had a disorder of glycogen breakdown that specifically affected skeletal muscle. The associated enzyme deficiency was discovered in 1959 by W. F. H. M. Mommaerts et al.
=== Protein === SIRT2 gene encodes a member of the sirtuin family of proteins, homologs to the yeast Sir2 protein. Members of the sirtuin family are characterized by a sirtuin core domain and grouped into four classes. The protein encoded by this gene is included in class I of the sirtuin family. Several transcript variants are resulted from alternative splicing of this gene. Only transcript variants 1 and 2 have confirmed protein products of physiological relevance. A leucine-rich nuclear export signal (NES) within the N-terminal region of these two isoforms is identified. Since deletion of the NES led to nucleocytoplasmic distribution, it is suggested to mediate their cytosolic localization.
Sources: en.wikipedia.org
vacuole Any of a class of enclosed, fluid-filled compartments present in many eukaryotic cells as well as bacteria, often large and conspicuous under the microscope and serving any of a huge variety of functions, including acting as a resizable reservoir for the storage of water, metabolic waste, toxins, or foreign material; maintaining cellular homeostasis and hydrostatic pressure; supporting immune functions; housing symbiotic bacteria; and assisting in the degradation and recycling of old cellular components.
In a light-emitting diode, the recombination of electrons and electron holes in a semiconductor produces light (infrared, visible or UV), a process called electroluminescence. The wavelength of the light depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of the devices, such as special optical coatings and die shape, are required to efficiently emit light. Unlike a laser, the light emitted from an LED is neither spectrally nor spatially coherent nor even highly monochromatic. Its spectrum is sufficiently narrow that it appears to the human eye as a pure (saturated) color. Also, it cannot approach the very high intensity characteristic of lasers.
Lieutenant Colonel James Edward Noel Bridgeman Shaw, Grenadier Guards, 559678; Brigade Major, Household Division, on the occasion of the Coronation of Their Majesties The King and The Queen. Nicholas Kester Smith, Director of Racing and Public Affairs, Ascot Racecourse. David William Courtenay Whelton, , Music Advisor, on the occasion of the Coronation of Their Majesties The King and The Queen. James Wyndham Williams, Music Advisor, on the occasion of the Coronation of Their Majesties The King and The Queen.
Sources: en.wikipedia.org
AOD9604 is a synthetic peptide based on a C-terminal segment of human growth hormone. It is manufactured by chemical peptide synthesis rather than extracted from human tissue. The sequence is often described as hGH fragment 176–191 or a close variant.
It is not approved as a prescription drug in the United States or the European Union for any indication. Regulatory status can differ by country, and it is often sold as a research chemical or in unapproved products. Such products are not equivalent to an approved medicine.
In the studies reported so far, AOD9604 does not appear to act through the growth hormone receptor and has not shown the typical IGF-1 increase caused by full-length hGH. Human data are limited, so this remains an area of uncertainty. It should not be assumed to have the same effects as hGH.
It is proposed to promote lipolysis in fat tissue, the breakdown of stored fat into fatty acids and glycerol. The detailed receptor and signaling mechanisms are not fully established.