AOD-9604 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-01-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Regulatory bodies have taken different approaches to AOD-9604. It is not approved as a prescription medicine by major agencies such as the U.S. Food and Drug Administration or the European Medicines Agency. In sport, the World Anti-Doping Agency prohibits peptide hormones, growth factors, and related substances, and AOD-9604 has been treated as a prohibited substance. These regulatory decisions reflect concerns about safety, efficacy, and potential misuse rather than proof of benefit.
Research on AOD-9604 also examines how the peptide is measured in biological samples. Analytical methods may include liquid chromatography coupled with mass spectrometry, immunoassays, or both. Detection can be challenging because the peptide is small and may be present at low concentrations. Published methods vary in sensitivity and specificity, so comparative interpretation requires attention to validation details. The presence of related hGH fragments can complicate identification in some matrices.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved as a medicine | Status varies by country; prohibited in sport. |
| Common storage temperature | 2–8 °C for lyophilized powder | Protect from light and moisture; follow supplier instructions. |
| Typical analytical method | LC-MS/MS | Used for identification and quantification in biological samples. |
| Purity assessment | HPLC and mass spectrometry | Reverse-phase HPLC is common for peptide purity. |
| Common synonyms | AOD9604; hGH 176-191 fragment | Naming conventions differ across studies. |
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.
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.
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.
It is not entirely clear why doxepin and first-generation antihistamines are different in this regard, but it has been suggested that it may have to do with the lack of selectivity for the H1 receptor of the latter or may have to do with the use of optimal doses. Unlike very-low-dose doxepin, most first-generation antihistamines also have marked anticholinergic activity as well as associated side effects such as dry mouth, constipation, urinary retention, and confusion. This is particularly true in older people, and antihistamines with concomitant anticholinergic effects are not recommended in adults over the age of 65. Anticholinergic activity notably may interfere with the sleep-promoting effects of H1 receptor blockade. Antagonism of the H1, 5-HT2A, 5-HT2C, and α1-adrenergic receptors is thought to have sleep-promoting effects and to be responsible for the sedative effects of TCAs including those of doxepin. Although doxepin is selective for the H1 receptor at doses lower than 25 mg, blockade of serotonin and adrenergic receptors may also be involved in the hypnotic effects of doxepin at higher doses. However, in contrast to very low doses of doxepin, rebound insomnia and daytime sedation are significantly more frequent than placebo with moderate doses (25 to 50 mg/day) of the drug. In addition, one study found that although such doses of doxepin improved sleep measures initially, most of the benefits were lost with chronic treatment (by 4 weeks).
The World Health Organization (WHO) recommends two doses of vaccine for all children. In countries with a high risk of disease the first dose should be given around nine months of age. Otherwise it can be given at twelve months of age. The second dose should be given at least one month after the first dose. This is often done at age 15 to 18 months. After one dose at the age of nine months 85% are immune, while a dose at twelve months results in 95% immunity. In the United States, the Centers for Disease Control and Prevention (CDC) recommends that children aged six to eleven months traveling outside the United States receive their first dose of MMR vaccine before departure and then receive two more doses; one at 12–15 months (12 months for children in high-risk areas) and the second as early as four weeks later. Otherwise the first dose is typically given at 12–15 months and the second at 4–6 years. In the UK, the National Health Service (NHS) recommendation is for a first dose at around 13 months of age and the second at three years and four months old. Health Canada recommends that children traveling outside North America should receive an MMR vaccine if they are aged six to 12 months. However, after the child is 12 months old they should receive two additional doses to ensure long-lasting protection.
=== Selectively neutral similarities === Similarities which have no adaptive relevance cannot be explained by convergent evolution, and therefore they provide compelling support for universal common descent. Such evidence has come from two areas: amino acid sequences and DNA sequences. Proteins with the same three-dimensional structure need not have identical amino acid sequences; any irrelevant similarity between the sequences is evidence for common descent. In certain cases, there are several codons (DNA triplets) that code redundantly for the same amino acid. Since many species use the same codon at the same place to specify an amino acid that can be represented by more than one codon, that is evidence for their sharing a recent common ancestor. Had the amino acid sequences come from different ancestors, they would have been coded for by any of the redundant codons, and since the correct amino acids would already have been in place, natural selection would not have driven any change in the codons, however much time was available. Genetic drift could change the codons, but it would be extremely unlikely to make all the redundant codons in a whole sequence match exactly across multiple lineages. Similarly, shared nucleotide sequences, especially where these are apparently neutral such as the positioning of introns and pseudogenes, provide strong evidence of common ancestry.
=== Derivation === This section presents a derivation of the equation above for electrons. A similar derivation can be found for the equation for holes. Consider the fact that the number of electrons is conserved across a volume of semiconductor material with cross-sectional area, A, and length, dx, along the x-axis. More precisely, one can say:
Sources: en.wikipedia.org
In the United States in 1999, there were 14,420 non-fatal traumatic amputations according to the American Statistical Association. Of these, 4,435 occurred as a result of traffic and transportation accidents and 9,985 were due to labor accidents. Of all traumatic amputations, the distribution percentage is 30.75% for traffic accidents and 69.24% for labor accidents. The United States Bureau of Labor Statistics reported 6,200 cases of work-related amputations in 2018. The most common causes of amputations were machinery (58% cases), crush injuries from parts or material (15%), and other tools/instruments/equipment such hand tools (7%). A study found that in 2010, 22.8% of patients undergoing amputation of a lower extremity in the United States were readmitted to the hospital within 30 days. In 2017, an estimated 57.7 million people globally were living with existing traumatic limb injuries. Of these 57.7 million, the leading causes of amputation "were falls (36.2%), road injuries (15.7%), other transportation injuries (11.2%), and mechanical forces (10.4%)." On 2 August 2023, an investigation by The Wall Street Journal found that Ukrainian medical amputations in the war came to between 20,000 and 50,000 including both military and civilians. In comparison, during World War One 41,000 British and 67,000 Germans needed amputations. In 2025, Israel's attacks on the Gaza Strip during the Gaza war caused Gaza to have the highest number of child amputees per capita in the world.
Bundle sheath chloroplasts do not carry out the light reactions, preventing oxygen from building up in them and disrupting RuBisCO activity. Because of this, they lack thylakoids organized into grana stacks—though bundle sheath chloroplasts still have free-floating thylakoids in the stroma where they still carry out cyclic electron flow, a light-driven method of synthesizing ATP to power the Calvin cycle without generating oxygen. They lack photosystem II, and only have photosystem I—the only protein complex needed for cyclic electron flow. Because the job of bundle sheath chloroplasts is to carry out the Calvin cycle and make sugar, they often contain large starch grains. Both types of chloroplast contain large amounts of chloroplast peripheral reticulum, which they use to get more surface area to transport stuff in and out of them. Mesophyll chloroplasts have a little more peripheral reticulum than bundle sheath chloroplasts.
=== Automobile systems === Urea is used in Selective Non-Catalytic Reduction (SNCR) and Selective Catalytic Reduction (SCR) reactions to reduce the NOx pollutants in exhaust gases from diesel, dual fuel, and lean-burn natural gas engines. The BlueTec system, for example, injects a water-based urea solution into the exhaust system. Ammonia (NH3) produced by the hydrolysis of urea reacts with nitrogen oxides (NOx) and is converted into nitrogen gas (N2) and water within the catalytic converter. The conversion of noxious NOx to innocuous N2 is described by the following simplified global equation:
Sources: en.wikipedia.org
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.
The World Anti-Doping Agency classifies growth hormone fragments, including AOD-9604, as prohibited substances. The classification reflects concern about potential performance-enhancing use. Athletes are subject to testing for such peptides.
Detection typically uses liquid chromatography combined with mass spectrometry. These methods separate the peptide and identify it by mass. Immunoassays may screen samples but require confirmation by a more specific technique.
No. It is not approved as a therapeutic drug by major regulators. It is sold for research purposes in many settings, which is not the same as clinical approval.