AOD-9604 vs Tesofensine
Growth hormone-derived lipolytic fragment vs central monoamine reuptake inhibitor — peptide vs small molecule approaches to fat metabolism research.
Last updated: 2026-03-08
Quick Comparison Table
| Category | AOD-9604 | Tesofensine |
|---|---|---|
| Drug Class | Modified GH fragment (amino acids 177-191) | Triple monoamine reuptake inhibitor |
| Primary Mechanism | Stimulates lipolysis, inhibits lipogenesis | Reduces appetite via dopamine/serotonin/noradrenaline |
| Administration | SC injection or oral | Oral tablet |
| Approval Status | TGA listed (Australia); not FDA/EMA approved | Phase III investigational |
| Effect on GH/IGF-1 | No effect on GH or IGF-1 levels | No direct effect on GH axis |
| Effect on Appetite | Minimal direct appetite effect | Significant appetite suppression |
| Weight Loss (Trials) | Modest results in Phase IIb (~1.6kg over 12 weeks) | ~12.8% body weight over 24 weeks |
| Key Safety Concern | Limited efficacy data; regulatory controversy | Cardiovascular stimulation (heart rate, BP) |
Mechanism of Action
AOD-9604
AOD-9604 Mechanism:
AOD-9604 (Anti-Obesity Drug 9604) is a modified fragment of human growth hormone, comprising amino acids 177-191 with an additional tyrosine at the N-terminus.
Key actions: 1. **Lipolysis stimulation** — Mimics the fat-mobilising action of GH without growth-promoting effects 2. **Lipogenesis inhibition** — Reduces new fat cell formation 3. **No IGF-1 elevation** — Unlike full GH, does not raise IGF-1 or affect blood glucose
AOD-9604 acts directly on adipose tissue via a specific binding site (not the GH receptor), stimulating beta-3 adrenergic-like fat mobilisation pathways. Its lack of effect on IGF-1, glucose, or growth makes it theoretically safer than GH for body composition.
The clinical evidence for AOD-9604's efficacy in humans has been disappointing relative to preclinical promise. Its TGA listing in Australia is as a food-grade ingredient, not a therapeutic drug.
Tesofensine
Tesofensine Mechanism:
Tesofensine blocks reuptake of three neurotransmitters: 1. **Dopamine** — Reduces food reward-seeking, enhances motivation 2. **Serotonin** — Increases central satiety signalling 3. **Noradrenaline** — Increases sympathetic tone and thermogenesis
It acts centrally on hypothalamic appetite circuits and mesolimbic reward pathways. Weight loss is driven primarily by appetite suppression (~80%) with a modest thermogenic contribution from noradrenergic activity.
Originally discovered during Alzheimer's research, consistent weight loss as a side effect prompted repurposing for obesity.
Clinical Trial Evidence
AOD-9604 Clinical Studies
Participants: 536
Duration: 12 weeks
Mean weight loss of 1.6kg with AOD-9604 vs 1.2kg placebo. Did not reach statistical significance for primary endpoint.
Not statistically significant
Participants: 0
Duration: 30 days
Significant fat mass reduction in ob/ob mice without affecting lean mass, food intake, or IGF-1 levels.
Statistically significant
Participants: 64
Duration: 4 weeks
No effect on IGF-1, glucose, insulin, or cortisol at doses up to 1000mcg/day SC. Confirmed metabolic safety.
Statistically significant
Participants: 30
Duration: Single dose
Oral AOD-9604 showed measurable plasma levels but lower bioavailability than SC injection. Oral formulation feasible.
Not statistically significant
Participants: 40
Duration: 24 weeks
Intra-articular AOD-9604 showed improvement in WOMAC pain scores for knee osteoarthritis. Potential cartilage repair activity.
Statistically significant
Tesofensine Clinical Studies
Participants: 203
Duration: 24 weeks
12.8% weight loss at 0.5mg vs 2.0% placebo. Dose-dependent appetite reduction across all groups.
Statistically significant
Participants: 140
Duration: 48 weeks
Sustained weight loss of ~10.6% at 0.5mg over 48 weeks.
Statistically significant
Participants: 203
Duration: 24 weeks
Improvements in waist circumference, fasting insulin, triglycerides, and adiponectin at 0.5mg.
Statistically significant
Participants: 203
Duration: 24 weeks
Mean HR increase of 7.4 bpm at 0.5mg; 1.0mg dose dropped due to cardiovascular concerns.
Not statistically significant
Participants: 31
Duration: 16 weeks
Significant reduction in hyperphagia and body fat in PWS patients with Tesomet. Novel application beyond general obesity.
Statistically significant
Benefits Comparison
AOD-9604 Unique Benefits
- No effect on IGF-1 or glucose metabolism
- Targets fat tissue directly
- Potential cartilage/joint benefits
- Minimal systemic side effects
- Available in oral form (Australia)
Shared Benefits
- Non-hormonal weight management approach
- Oral formulation potential
- Investigational status for obesity
Tesofensine Unique Benefits
- Significantly greater weight loss efficacy
- Rapid onset of appetite suppression
- Improvements in metabolic biomarkers
- Oral tablet formulation
- Potential Prader-Willi Syndrome application
Research & Evidence
AOD-9604 Research
AOD-9604's human evidence is limited. The pivotal Phase IIb trial (536 patients) failed to demonstrate clinically meaningful weight loss over placebo. Development for obesity was effectively abandoned after 2007. Recent repurposing for osteoarthritis shows more promise. Its TGA listing is as a food ingredient, not a registered therapeutic.
Tesofensine Research
Tesofensine's Phase II data (203 patients) showed the highest weight loss of any obesity drug in development at the time. Development continues as Tesomet (+ Metoprolol) with Phase III studies ongoing for obesity and Prader-Willi Syndrome. The evidence base is small but more convincing than AOD-9604's for weight loss.
Head-to-Head Analysis
Direct Comparison:
No head-to-head trial exists.
Efficacy Gap: Tesofensine produced dramatically greater weight loss in Phase II trials (~12.8% at 0.5mg/24 weeks) compared to AOD-9604's Phase IIb (~1.6kg over 12 weeks). This represents a substantial efficacy difference.
Mechanism Difference: AOD-9604 acts peripherally on fat tissue; Tesofensine acts centrally on appetite. Central appetite suppression has consistently shown greater efficacy for total weight loss than peripheral lipolytic approaches.
Development Status: Neither is approved as a weight loss drug in the EU/UK. AOD-9604 failed to progress past Phase IIb due to disappointing efficacy. Tesofensine continues Phase III development as Tesomet (with Metoprolol).
Protocol Comparison
AOD-9604 Protocol
AOD-9604 Theoretical Protocols (Research-Based):
Dosing: Phase II used 100-1000mcg/day SC injection. Common research dose cited: 250-300mcg SC daily. Oral dose (Australia): 600mg as food-grade supplement.
Routes: - Subcutaneous injection - Oral (lower bioavailability)
Timing: Typically discussed as morning fasted administration.
⚠️ Disclaimer: No approved therapeutic protocol exists for AOD-9604 as a weight loss drug.
Tesofensine Protocol
Tesofensine Theoretical Protocols (Research-Based):
Dosing: Phase II: 0.25mg, 0.5mg, 1.0mg oral daily. 0.5mg was the optimal dose.
Routes: - Oral tablet — once daily
Duration: 24-48 week studies conducted. Optimal duration not established.
⚠️ Disclaimer: Tesofensine is not approved for clinical use.
Safety Profiles
AOD-9604 Safety
AOD-9604 Safety Profile:
Well-tolerated in clinical studies. No significant adverse effects on glucose, insulin, IGF-1, or cortisol levels. Injection site reactions were the most common side effect.
Primary concern: Efficacy, not safety. The peptide's safety profile is actually its strongest attribute — it lacks the metabolic perturbations of GH therapy.
Regulatory note: TGA listing in Australia is as a food-grade ingredient with a different regulatory standard than therapeutic approval.
Tesofensine Safety
Tesofensine Safety Profile:
Common: Dry mouth (34%), nausea (22%), constipation (19%), insomnia (17%).
Cardiovascular: Heart rate increase (+7.4 bpm at 0.5mg). The 1.0mg dose was dropped due to unfavourable CV profile.
CNS: Insomnia, anxiety possible at higher doses.
The Tesomet formulation (+ Metoprolol) was developed specifically to mitigate cardiovascular stimulation. Phase III safety data is pending.
The Verdict
These represent very different approaches. Tesofensine is significantly more effective for weight loss but carries cardiovascular safety concerns. AOD-9604 is remarkably safe but failed to demonstrate meaningful weight loss in human trials. For researchers interested in fat metabolism, AOD-9604 remains interesting mechanistically but clinically disappointing. Tesofensine, if its cardiovascular profile can be managed (via Tesomet), has genuine therapeutic potential. Neither is currently approved for weight loss.
Frequently Asked Questions
Conclusion
AOD-9604 and Tesofensine exemplify the contrast between peripheral and central approaches to obesity pharmacotherapy. AOD-9604's elegant mechanism — targeting fat metabolism without hormonal effects — unfortunately did not translate to meaningful clinical weight loss. Tesofensine's potent central appetite suppression produces substantial weight loss but with cardiovascular trade-offs under investigation. For current weight loss research, Tesofensine holds more promise; AOD-9604's future may lie in joint health rather than obesity.
Medical Disclaimer
The information provided in this comparison is for educational and research purposes only. Neither AOD-9604 nor Tesofensine is approved for human therapeutic use by the MHRA, EMA, or FDA. This content does not constitute medical advice. Always consult a qualified healthcare professional before considering any peptide or supplement.