This is a working overview of AOD-9604, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-05. Anything still debated is marked as such rather than presented as settled.
AOD-9604 is a synthetic peptide whose sequence matches the C-terminal fragment of human growth hormone, specifically residues 176 through 191. This region differs from the full hormone in its receptor interactions. The peptide is not a growth hormone secretagogue and does not bind the growth hormone receptor in the same manner. Researchers have examined it for effects on lipid metabolism, but its exact pharmacological profile remains an active area of study.
Development of AOD-9604 began in the 1990s as scientists sought to isolate metabolic effects of growth hormone without its growth-promoting actions. Early laboratory work focused on fat cells and animal models. Several human trials followed, examining changes in body composition and fat mass. Results have been mixed, and the peptide has not progressed to widespread clinical approval. Interest continues in research settings, particularly regarding its mechanism and potential metabolic targets.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Peptide fragment | Corresponds to hGH residues 176-191 |
| Common synonyms | AOD9604, hGH 176-191 | Also written as AOD-9604 |
| Typical form | Lyophilized powder | Often supplied in sealed vials |
| Solubility | Water-soluble | Dissolves in aqueous buffers |
| Regulatory status | Not approved as drug | Banned in sport; varies by country |
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.
Early interest in AOD-9604 centered on whether a fragment of human growth hormone could influence fat metabolism without the broader effects of the full hormone. Cell and animal studies reported changes in fat storage and breakdown. Human trials followed, but the results were not strong enough to secure regulatory approval. The compound remains available for laboratory research, and its clinical potential is still described as uncertain. Studies continue to examine its activity and safety profile.
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.
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.
A reduction in the starting dose is recommended for patients who are CYP2D6 intermediate metabolizers and CYP2C19 poor metabolizers. If the use of amitriptyline is warranted, therapeutic drug monitoring is recommended to guide dose adjustments. The Dutch Pharmacogenetics Working Group also recommends selecting an alternative drug or monitoring plasma concentrations of amitriptyline in patients who are CYP2D6 poor or ultrarapid metabolizers, and selecting an alternative drug or reducing initial dose in patients who are CYP2D6 intermediate metabolizers.
The FDA has not approved any acellular dermal matrix products for use in implant-based breast reconstruction following surgery to remove a breast tumour, as the published literature suggests that different ADM products may have different risk profiles, thus clinical results may not be consistent.
Advantages In addition to the kinetic advantages, the reaction relies heavily on small molecules, which are easier to modify and scale. Tetrazine ligations are gaining more importance in various applications, including monitoring lipid modifications, imaging circulating tumor cells, and analyzing glycosylation. Furthermore, they are emerging as highly suitable for click-to-release reactions that are being utilized in regulating enzyme activity and drug delivery.
Sources: en.wikipedia.org
=== Metabolism === Because calciseptine is a peptide, theoretically it can be broken down by proteases in the tissues where it is injected. It has been found that digestion of snake toxic peptides by proteases does occur in the prey tissues, but due to the relative stability of the toxins, the speed with which the toxins act and the amount of venom injected, this is not enough to protect against the consequences of a snake bite. The same goes for the immune system: the larger venom peptides are unlikely to be missed by the immune system, but immunological action is not fast enough to counter the effects of the venom. As mentioned above, calciseptine has a three-fingered structure commonly found in toxins. Although many toxins have this structure, their functions are diverse. The reason this structure is so much conserved is probably its stability: the cysteine bridges create a stable core, which possibly slows the breakdown of the protein by proteases.
To reduce the peptidic nature of ketomethylene inhibitors the P1’ and P2’ substituent may be cyclized to form a lactam, where there is a correlation between the inhibitory potency and the ring size. In 2001 it was postulated that a substitution α to nitrogen and making of 3-methyl-substituted analog of A58365A, a pyridone acid isolated from the fermentation broth of the bacterium Streptomyces chromofuscus with ACE inhibitory activity, might influence the level of biological activity by steric or hydrophobic effect, and/or by preventing reactions at C3. It was also noticed during the synthetic work on A58365A that potential precursors were sensitive to oxidation of the five-membered ring and so the 3-methyl analogue might be more stable in this respect.
=== Hobbies === Bush has been an avid reader throughout his adult life, preferring biographies and histories. During his presidency, Bush read the Bible daily, though at the end of his second term he said on television that he is "not a literalist" about Bible interpretation. Walt Harrington, a journalist, recalled seeing "books by John Fowles, F. Scott Fitzgerald, James Joyce, and Gore Vidal lying about, as well as biographies of Willa Cather and Queen Victoria" in his home when Bush was a Texas oilman. Other activities include cigar smoking and golf. Bush has also painted many paintings. One of his best-known projects is a collection of 43 paintings of immigrants, titled Out of Many, One. Another painting project was Portraits of Courage: A Commander in Chief's Tribute to America's Warrior.
After sodium thiopental began being used in executions, Hospira, the only American company that made the drug, stopped manufacturing it due to its use in executions. The subsequent nationwide shortage of sodium thiopental led states to seek other drugs to use in executions. Pentobarbital, often used for animal euthanasia, was used as part of a three-drug cocktail for the first time on December 16, 2010, when John David Duty was executed in Oklahoma. It was then used as the drug in a single-drug execution for the first time on March 10, 2011, when Johnnie Baston was executed in Ohio.
Sources: en.wikipedia.org
AOD-9604 is a synthetic peptide fragment of human growth hormone, corresponding to amino acids 176-191. It is studied for potential effects on fat metabolism, but it is not approved as a drug in most countries. Its exact mechanism remains under investigation.
No, it is a small fragment of the full growth hormone protein. It does not appear to stimulate growth or increase growth hormone levels in the same way. Its actions are thought to be more limited to metabolic pathways.
Regulatory status varies. It is not approved for medical use in the United States or many other countries. It is banned in sport by WADA, and its sale as a supplement or research chemical may be subject to legal restrictions.
It is a synthetic peptide based on a C-terminal fragment of human growth hormone. It is commonly referred to as hGH fragment 176-191 and is studied for metabolic effects rather than growth effects.