AOD-9604 — Research Overview
Chemical Name: Tyr-hGH (177-191), modified C-terminal fragment of human growth hormone Also Known As: AOD9604, Anti-Obesity Drug 9604, HGH Fragment 176-191 analog Developer: Metabolic Pharmaceuticals, Australia. Research originated at Monash University, Melbourne. Structure: 15 amino acid synthetic peptide derived from the C-terminal region of human growth hormone with an added tyrosine residue at the N-terminus Category: Growth hormone fragment analog / lipolytic research peptide
Research Use Only — Disclaimer
The scientific literature on this page is provided strictly for educational and informational purposes. All Rogue Compounds products are intended for in-vitro laboratory research use only and are not approved by the FDA for human or animal consumption. The studies referenced below are independent third-party peer-reviewed publications. Rogue Compounds makes no claims that any product diagnoses, treats, cures, or prevents any disease or condition. Researchers are responsible for compliance with all applicable local, state, and federal regulations.
What Is AOD-9604?
AOD-9604 is a synthetic peptide fragment derived from the C-terminal region of human growth hormone, specifically corresponding to amino acids 177 through 191 of the full HGH sequence, with a tyrosine residue added to the N-terminus to enhance stability and lipolytic activity. It was originally developed by Metabolic Pharmaceuticals in Australia as a potential pharmaceutical treatment for obesity, based on the hypothesis that the fat-metabolizing properties of full-length human growth hormone could be isolated in a shorter fragment that avoided the broader hormonal effects of complete HGH therapy.
The name AOD stands for Anti-Obesity Drug, reflecting its original therapeutic intent. The key design principle behind AOD-9604 is that it retains the lipolytic and anti-lipogenic properties of the C-terminal region of HGH while not activating the classical growth hormone receptor, not elevating IGF-1 levels, and not affecting blood glucose or insulin secretion — all of which are significant side effects associated with full-length HGH administration.
AOD-9604 advanced through Phase I and Phase IIa clinical trials and received Generally Recognized As Safe (GRAS) status from the US Food and Drug Administration for oral consumption at specified levels during its development period. Clinical development as a standalone obesity pharmaceutical was ultimately discontinued after a 24-week Phase IIb trial in 536 subjects failed to meet the primary efficacy endpoint for clinically significant weight reduction. The compound continues to be studied in laboratory research settings for its lipolytic mechanism and emerging cartilage and joint biology applications.
Mechanism of Action
AOD-9604 exerts its primary effects through a receptor-independent lipolytic mechanism that does not require binding to the classical growth hormone receptor. Research has identified the following primary mechanisms in preclinical models.
Lipolysis stimulation: AOD-9604 promotes the hydrolysis of stored triglycerides in adipose tissue into free fatty acids and glycerol, accelerating fat mobilization from adipocytes.
Anti-lipogenesis: Simultaneously with stimulating fat breakdown, AOD-9604 inhibits de novo lipogenesis — the synthesis of new fatty acids from non-fat precursors — in adipose tissue. This dual action distinguishes it from many lipolytic agents that only stimulate breakdown without reducing new fat formation.
Beta-3 adrenergic receptor pathway interaction: Published research demonstrates that AOD-9604 increases the expression of beta-3 adrenergic receptor RNA in adipose tissue. The beta-3 adrenergic receptor is the primary lipolytic receptor in fat cells and its expression is characteristically suppressed in obese animals. AOD-9604 treatment has been shown to restore beta-3 AR RNA expression in obese mice to levels comparable to those seen in lean controls, suggesting a mechanism involving enhanced lipolytic sensitivity rather than direct receptor binding.
No IGF-1 elevation: Unlike full-length HGH, AOD-9604 does not stimulate IGF-1 production, does not activate the somatogenic signaling cascade of the growth hormone receptor, and does not promote cell proliferation via HGH receptor pathways.
No glycemic disruption: Preclinical studies consistently show that AOD-9604 does not induce hyperglycemia or reduce insulin secretion — a critical distinction from full-length HGH which produces significant insulin resistance at therapeutic doses.
Cartilage and chondrocyte activity: Separately from its metabolic effects, research has identified that AOD-9604 promotes proteoglycan and collagen production in chondrocytes and shows chondroprotective effects in osteoarthritis animal models, opening a secondary area of research interest beyond fat metabolism.
Published Research
Study 1 — Foundational Preclinical Study: Fat Oxidation and Weight Loss in Obese Mice
Authors: Heffernan MA, Thorburn AW, Fam B, Summers R, Conway-Campbell B, Waters MJ, Ng FM Year: 2001 Journal: International Journal of Obesity PMID: 11673763 Full text: https://pubmed.ncbi.nlm.nih.gov/11673763/
This foundational study examined the chronic effects of both full-length human growth hormone and AOD-9604 on body weight, energy balance, and substrate oxidation in obese ob/ob mice and lean C57BL/6J mice over 14 days. It also used in vitro assays to determine whether AOD-9604 acts through the classical HGH receptor.
Both HGH and AOD-9604 significantly reduced body weight gain in obese mice. This was associated with increased in vivo fat oxidation and elevated plasma glycerol levels, confirming active lipolysis.
Unlike HGH, AOD-9604 did not induce hyperglycemia or reduce insulin secretion, establishing its metabolic selectivity.
AOD-9604 did not compete for the HGH receptor in receptor binding assays and did not induce cell proliferation via the HGH receptor, confirming a novel receptor-independent mechanism.
The authors concluded that fragments of HGH can act through pathways novel to traditional HGH-stimulated signaling, and that the concept of HGH behaving as a pro-hormone with discrete functional domains is further supported by these findings.
Study 2 — Beta-3 Adrenergic Receptor Mechanism: Lipid Metabolism in Obese and Knockout Mice
Authors: Heffernan M, Summers RJ, Thorburn A, Ogru E, Gianello R, Jiang WJ, Ng FM Year: 2001 Journal: Endocrinology, Oxford Academic PMID: 11713213 Full text: https://pubmed.ncbi.nlm.nih.gov/11713213/
This study examined the mechanism by which AOD-9604 produces its lipolytic effects, focusing specifically on the role of beta-3 adrenergic receptors. Researchers used both standard obese mice and beta-3 AR knockout mice to isolate the contribution of this pathway.
Both HGH and AOD-9604 reduced body weight and body fat in obese mice following 14 days of chronic administration.
These results correlated with increased expression levels of beta-3 adrenergic receptor RNA, the major lipolytic receptor found in fat cells. Both compounds restored the suppressed beta-3 AR RNA expression in obese mice to levels comparable to those in lean controls.
When tested in beta-3 AR knockout mice under long-term treatment conditions, neither HGH nor AOD-9604 produced the body weight change or increase in lipolysis seen in wild-type mice, confirming the pathway’s importance in chronic lipolytic response.
However in an acute experiment AOD-9604 was capable of increasing energy expenditure and fat oxidation even in beta-3 AR knockout mice, suggesting that while the beta-3 AR pathway is important for sustained chronic effects, AOD-9604 also has acute lipolytic mechanisms that operate independently of this receptor.
The authors concluded that the lipolytic actions of AOD-9604 are not mediated directly through the beta-3 AR, although the compound increases beta-3 AR expression in a way that may subsequently contribute to enhanced lipolytic sensitivity over time.
Study 3 — Phase IIa Human Clinical Trial: Lipolysis in Obese Men
Authors: Ng FM et al. Journal: Obesity Research PMID: 16339126 Full text: https://pubmed.ncbi.nlm.nih.gov/16339126/
This randomized controlled trial evaluated AOD-9604 in obese human subjects, representing one of the early human clinical investigations of the compound. Key findings from this study:
AOD-9604 stimulated lipolysis in obese men as measured by objective metabolic endpoints.
In a 12-week randomized clinical trial subjects receiving AOD-9604 at 1 mg per day lost an average of 2.6 kg compared to 0.8 kg in the placebo group, representing a statistically significant difference in the short-term trial window.
The compound was well tolerated in the study population. No serious adverse events were reported.
These early Phase IIa results provided the basis for advancing to larger Phase IIb trials. The subsequent 24-week Phase IIb trial in 536 subjects did not demonstrate clinically significant weight reduction sufficient to support pharmaceutical development, leading to discontinuation of the obesity drug program in 2007. The short-term Phase IIa data remains part of the published scientific record.
Study 4 — Cartilage Regeneration in Osteoarthritis Animal Model
Authors: Kwon DR, Park GY Year: 2015 Journal: Annals of Clinical and Laboratory Science PMID: 26275694 Full text: https://pubmed.ncbi.nlm.nih.gov/26275694/
This study examined AOD-9604 in a collagenase-induced knee osteoarthritis rabbit model, representing a distinct and emerging area of research interest beyond fat metabolism. Thirty-two mature New Zealand white rabbits received collagenase injections to induce knee osteoarthritis and were then randomized into four treatment groups: saline control, hyaluronic acid alone, AOD-9604 alone, and AOD-9604 combined with hyaluronic acid. Weekly intra-articular injections were administered for 4 to 7 weeks and cartilage was assessed at 8 weeks through morphological and histopathological analysis.
Mean gross morphological and histopathological scores were significantly higher in the saline control group than in all treatment groups, confirming active cartilage degeneration in untreated animals.
Intra-articular AOD-9604 injections using ultrasound guidance produced enhanced cartilage regeneration compared to saline controls.
The combined AOD-9604 and hyaluronic acid group showed significantly lower cartilage degeneration scores than either AOD-9604 alone or hyaluronic acid alone, indicating an additive or synergistic effect between the two compounds.
The lameness period in the combined treatment group was significantly shorter than in all other groups, suggesting improved joint function alongside the structural cartilage improvements.
The authors concluded that intra-articular AOD-9604 injections enhanced cartilage regeneration and that combined AOD-9604 and hyaluronic acid treatment was more effective than either agent alone in this osteoarthritis model. The researchers noted that AOD-9604 promotes proteoglycan and collagen production in chondrocytes, which may underlie its chondroprotective effects.
Study 5 — Beta-3 AR Knockout Confirmation and Obesity Pharmacotherapy Context
Authors: Bray GA, Ryan DH et al. Year: 2012 Journal: PMC — Obesity Pharmacotherapy: Current Perspectives and Future Directions PMCID: PMC3584306 Full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC3584306/
This comprehensive review of obesity pharmacotherapy places AOD-9604 within the broader context of anti-obesity drug development and summarizes the compound’s clinical trial history. Key points from this review relevant to AOD-9604:
AOD-9604 is described as an orally active analog of the HGH peptide fragment 177 to 191 that selectively activates lipolysis in adipose tissue.
In preclinical models AOD-9604 reduced body weight in genetically obese Zucker rats and ob/ob mice without inducing the adverse glycemic effects normally observed with growth hormone treatment.
The 12-week randomized clinical trial showed 2.6 kg mean weight loss versus 0.8 kg for placebo. The subsequent 24-week trial in 536 subjects did not demonstrate sufficient efficacy and development was terminated in 2007.
The review positions AOD-9604 as a compound that successfully demonstrated target engagement and favorable safety but failed to achieve the magnitude of weight loss required for commercial obesity drug development at the doses studied.
Current Research Status and Limitations
AOD-9604 completed Phase I and Phase IIa clinical trials with generally favorable safety data and demonstrated proof-of-concept lipolytic activity in human subjects. The Phase IIb development program for obesity was formally discontinued in 2007 following insufficient efficacy in the larger longer-duration trial.
AOD-9604 received GRAS status from the FDA for oral consumption at specified levels during its development period, which is notable as this designation requires a formal toxicological review process. This applies specifically to the oral administration route and specified concentration levels evaluated during the pharmaceutical development program.
The cartilage and osteoarthritis research represents an emerging secondary area of investigation that was not part of the original obesity development program. Published data in this area is currently limited to preclinical animal models and in vitro chondrocyte studies. No human clinical trials of AOD-9604 for cartilage or joint applications have been published.
The following remain unestablished in the current published literature:
Long-term safety profile beyond the clinical trial observation windows.
Efficacy in human populations for applications beyond the studied obesity indication.
Human clinical data for cartilage or joint applications.
Optimal dosing parameters for research protocols across different applications.
Reconstitution Note
AOD-9604 is a peptide compound that requires reconstitution prior to use in laboratory research protocols. Acetic acid (0.6%) is commonly specified as the primary reconstitution solvent for AOD-9604 in published research protocols due to its hydrophobic sequence characteristics. A two-step protocol is standard: initial dissolution in a small volume of 0.6% acetic acid followed by dilution to working concentration with bacteriostatic water or sterile saline. Always confirm the recommended solvent against the specific lot datasheet before reconstitution.
In-Use Period and Storage
Before Reconstitution — Lyophilized Powder
Rogue Compounds stores all products refrigerated prior to shipping to maintain compound integrity from production through to delivery. Upon receipt researchers should store vials at 2 to 8 degrees Celsius immediately. Keep vials sealed, dry, and away from direct light until ready for use. Do not freeze. Repeated freeze-thaw cycling has been documented in peer-reviewed pharmaceutical formulation literature to accelerate structural degradation even in dry powder form, potentially compromising molecular integrity and experimental reproducibility.
Why We Refrigerate Instead of Freeze
Freezing and thawing introduces mechanical and osmotic stress at the molecular level. Published pharmaceutical research identifies freeze-thaw cycling as a significant risk factor for loss of structural integrity in peptides and protein-based compounds. To protect compound quality at every stage of handling and fulfillment, Rogue Compounds maintains refrigerated rather than frozen cold chain storage throughout the entire process.
After Reconstitution — Liquid Solution
Store reconstituted solutions refrigerated at 2 to 8 degrees Celsius immediately after preparation. Protect from light at all stages of storage and handling. Avoid repeated freeze-thaw cycles of reconstituted solutions regardless of the diluent used. Use within the timeframe recommended for the individual compound. Label each aliquot with the compound name, concentration, date of reconstitution, and diluent used. Discard any solution that shows visible particulate matter, discoloration, or signs of contamination.
Note: Storage and in-use recommendations on this page are provided as general laboratory guidance based on standard peptide handling practices documented in peer-reviewed pharmaceutical literature. Researchers should always refer to the individual compound’s published research literature and datasheet for any specific requirements. All products sold by Rogue Compounds are intended strictly for in-vitro laboratory research use only.
Available from Rogue Compounds
View the AOD-9604 product page: https://roguecompounds.com/product/aod-9604/