A practical reference on synthetic peptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-02-02 and is reviewed periodically as new material appears.
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.
Regulatory treatment of AOD-9604 is shaped by its classification as a peptide hormone. The World Anti-Doping Agency lists it as a prohibited substance, and many national anti-doping organizations adopt that list. It does not hold approval as a prescription medicine in the United States, the European Union, or other major markets. Products sold online are frequently labeled for research use only and may not undergo independent quality testing. Import and possession rules differ by country, so legal status depends on local law.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C | Lyophilized peptide; protect from moisture and light. |
| Typical analytical method | HPLC and mass spectrometry | Used to confirm identity and estimate purity. |
| Common synonyms | AOD9604; hGH 176-191 | Naming varies by supplier and publication. |
| Disulfide bonds | One | Affects folded structure and stability. |
| Typical research purity | ≥95% | Value depends on supplier and analytical method. |
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 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.
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.
Laboratory studies have reported that AOD9604 can increase lipolysis and reduce lipid accumulation in fat cells. The precise molecular target remains uncertain, and the compound does not appear to activate the growth hormone receptor in the same way as full-length hGH. Proposed mechanisms include effects on beta-adrenergic signaling and enzymes involved in fatty acid synthesis, but these pathways are not firmly established. Because most evidence comes from cell and animal models, whether the same effects occur in humans is an open question.
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.
== Publications == Phil S. Baran has authored and co-authored approximately 300 research publications with an h-index of 133 and over 60,000 citations. His group's research has been published in journals including Science, Nature, Journal of American Chemical Society (JACS), Angewandte Chemie, and Journal of Organic Chemistry (JOC). Baran has authored the digital interactive reference text The Portable Chemist's Consultant: A Survival Guide for Discovery, Process, and Radiolabeling and contributed chapters and forewords to several scientific publications.
=== Dissolving microneedles === Dissolving MNs are mostly composed of water-soluble drugs that enable the dissolution of MN tips when inserted into skin. This is a one-step approach which does not require the removal of MNs and is convenient for long-term therapy. However, incomplete insertion and delay dissolution is observed with the use of dissolving MNs. This polymer would allow the drug to be delivered into the skin and could be broken down once inside the body. Pharmaceutical companies and researchers have begun to study and implement polymers such as Fibroin, a silk-based protein that can be molded into structures like microneedles and dissolved once in the body.
Like HMB, creatine is an ergogenic aid that appears to improve anaerobic capacity and muscle mass in individuals who perform high-intensity exercise. When supplemented together, studies have suggested that creatine produces a synergistic effect that can augment HMB-induced improvements on aerobic and anaerobic performance, endurance, and lean body mass in exercise programs of sufficient intensity, relative to HMB alone. In 2006, only about 2% of college student athletes in the United States used HMB as a dietary supplement. As of 2017, HMB has found widespread use as an ergogenic supplement among athletes. As of 2018, HMB has not been banned by the National Collegiate Athletic Association, World Anti-Doping Agency, or any other prominent national or international athletic organization.
==== List of P-CABs in the markets (First year of approval for clinical use) ==== Revaprazan (2006) Vonoprazan (2014) Tegoprazan (2018) Fexuprazan (2021) Keverprazan (2023/China) Zastaprazan (2024/South Korea)
The earliest efforts used methods similar to those used by Dayhoff, using large-scale matching of the protein database to generate a new log-odds matrix and the JTT (Jones-Taylor-Thornton) model. The rapid increases in compute power in the 21st century (reflecting factors such as Moore's law) made it feasible to estimate parameters for empirical models using maximum likelihood (e.g., the WAG and LG models) and other methods (e.g., the VT and PMB models). The IQ-Tree software package allows users to infer their own time reversible model using QMaker, or non-time-reversible using nQMaker. These methods produce both a tree and a best-fitting matrix. GTR is also available in IQ-Tree. The inference of custom models and GTR require a relatively large alignment due to the large number of parameters involved. As a consequence, a large number of empirical substitution models of protein evolution are currently available. These substitution models are derived from protein sequences of different taxonomic groups and protein families such as nuclear proteins, chloroplast proteins, mitochondrial proteins, and viral proteins, among others. A singular empirical model assume a constant set of amino acid frequencies over the entire evolutionary tree, which is often not the case over wide-spanning trees. The Bayesian CAT model was introduced in 2004. Maximum-likelihood version of it with 10–60 empirical profiles (C10–C60) were introduced in 2008. These methods are available in PhyML and IQ-TREE.
Sources: en.wikipedia.org
=== Size-Exclusion Chromatography (Gel Filtration) === Size-exclusion chromatography separates proteins based on their size. The stationary phase is composed of porous beads that allow smaller molecules to enter the pores while larger molecules pass around them. As a result, larger proteins elute first, followed by smaller ones. This method is particularly useful for desalting or removing small contaminants from protein samples.
Changes in nearby tissue is not the only possible impact of ligand therapy, there may be immunologic responses from the target tissue that cause changes remotely. This has been dubbed the "abscopal effect". While this mechanism is not well understood, it explains the impact of other tissue, both benign and malignant, after targeted radiotherapy.
(ICH E6) Any board, committee, or other group formally designated by an institution to review biomedical research involving humans as subjects, to approve the initiation of and conduct periodic review of such research. (21CFR50.3) Intent to treat
=== Murder of Charmaine West === Rose is believed to have murdered Charmaine shortly before Fred's prison release date of 24 June 1971. She is known to have taken Charmaine, Anne Marie and Heather to visit Fred on 15 June, and it is believed that Charmaine was killed on or very shortly after this date. As well as forensic dentistry confirming that Charmaine had died while Fred was still incarcerated, further testimony from Tracey Giles' mother, Shirley, corroborated the fact that Charmaine had died before Fred's release. In her later testimony at Rose's trial, Shirley stated that her two daughters had been playmates of Charmaine and Anne Marie when her family lived in the upper flat of 25 Midland Road in 1971. Shirley further stated that after her family had vacated the flat in April 1971, she had brought Tracey to visit Charmaine on a day in June, only for Tracey to be told by Rose: "She's gone to live with her mother, and bloody good riddance!" Shirley Giles was adamant that Fred was still in prison on this occasion. As with the Giles family, Rose explained Charmaine's disappearance to others who enquired about her whereabouts by claiming that Fred's first wife, Catherine "Rena" West, had taken her eldest daughter to live with her in Bristol. She contradictorily informed staff at Charmaine's primary school that the child had moved with her mother to London. When Fred was released from prison on 24 June, he allayed Anne Marie's concerns for her sister's whereabouts by claiming Rena had collected Charmaine and returned to her native Scotland.
Sources: en.wikipedia.org
No. Major drug regulators have not approved AOD-9604 for weight loss or any other therapeutic indication. It remains an investigational compound studied in research settings.
The World Anti-Doping Agency classifies it as a prohibited peptide hormone. Athletes under anti-doping rules are not permitted to use it. Its presence can trigger a doping violation.
It is a fragment of growth hormone rather than a substance that signals the pituitary to release more hormone. Studies have not shown a consistent rise in IGF-1 or full growth hormone. Its metabolic effects, if any, appear separate from those of the complete hormone.
No major regulatory agency has approved AOD-9604 as a medicine. It is treated as an experimental peptide in research settings. Some countries restrict its sale or import.