How GLP-1 agonists, GH peptides, and fat-targeting compounds compare — with real pricing
Last updated: April 2026 | Research use only — not medical advice
This guide covers research peptides and pharmaceutical compounds studied for weight loss. Prescription drugs (semaglutide, tirzepatide) require a physician's supervision. Research peptides are sold for laboratory use only. Nothing here constitutes medical advice. Always consult a licensed physician before starting any weight management program.
Not all weight loss peptides are equal in terms of evidence. Understanding the evidence tier helps you evaluate claims and set realistic expectations.
Semaglutide and tirzepatide. Large Phase 3 randomized controlled trials. Approved as drugs. Strongest evidence base. Require prescription and medical supervision.
Retatrutide (Phase 3 ongoing), AOD-9604 (Phase 2/3 completed — mixed results). Real human trial data, but not yet approved or results insufficient for approval.
GH peptides (CJC-1295, Hexarelin, Sermorelin). GH promotes lipolysis — a real mechanism. But no direct weight loss RCT evidence. Body composition evidence, not total weight loss.
GLP-1 (glucagon-like peptide-1) receptor agonists are the most researched and clinically proven class of weight loss peptides. They work primarily by reducing appetite, slowing gastric emptying, and improving insulin sensitivity — creating a sustainable caloric deficit without pure willpower.
Semaglutide is the most widely studied GLP-1 agonist for weight loss. The STEP trial program established ~15–17% average body weight loss at 68 weeks with 2.4mg/week. It's available as Ozempic (diabetes), Wegovy (weight loss), and Rybelsus (oral). Through telehealth, programs cost $149–$399/month using compounded semaglutide.
Mechanism: GLP-1 receptor agonist → reduces appetite, slows gastric emptying, increases satiety signals, improves insulin sensitivity. Also has direct CNS appetite-suppression effects at the level of the hypothalamus.
→ Full Semaglutide Price Guide (research peptide pricing)Tirzepatide adds GIP receptor agonism to GLP-1 action, creating a dual mechanism that has consistently outperformed semaglutide in head-to-head and comparative trials. The SURMOUNT trials demonstrated ~20–22% average weight loss. Available as Mounjaro (diabetes) and Zepbound (weight loss). Telehealth programs: $199–$499/month.
Mechanism: Dual GLP-1 + GIP agonist. GIP receptor activation appears to enhance the metabolic effects of GLP-1 agonism and may improve tolerability by reducing some of the nausea burden of pure GLP-1 agonists.
→ Full Tirzepatide Price Guide (research peptide pricing)Retatrutide (LY3437943) is Eli Lilly's triple agonist targeting GLP-1, GIP, AND glucagon receptors. The Phase 2 TRIUMPH trial showed ~24% average weight loss at 48 weeks — the highest average in any published peptide weight loss trial to date. Phase 3 is underway. Not yet FDA-approved and not available as a prescription drug, but research-grade peptide is available from suppliers.
Mechanism: Triple GLP-1/GIP/glucagon agonism. The glucagon component increases energy expenditure and fat oxidation, adding a metabolic "burning" dimension to the appetite-suppressing effects of GLP-1 agonism.
→ Full Retatrutide Price GuideA separate category of weight loss research focuses on growth hormone fragments and GH-related peptides that target fat metabolism specifically, rather than appetite regulation. The theory is appealing — selectively enhance fat burning without hunger reduction — but human data has been disappointing so far.
AOD-9604 (fragment 176–191 of HGH) was developed at Monash University specifically to isolate the lipolytic (fat-burning) properties of growth hormone without the insulin and growth-promoting side effects. Animal studies showed strong fat loss effects. Australian TGA granted food additive status. However, human Phase 2b/3 trials by Metabolic Pharmaceuticals did not demonstrate the statistically significant weight loss required for drug approval. The discrepancy between animal and human results is significant and should temper expectations.
It remains widely available as a research peptide and is studied for potential joint health benefits (separate from fat loss), where some animal data is more encouraging.
→ Full AOD-9604 Price GuideGH-stimulating peptides don't produce weight loss on a scale in the same way GLP-1 agonists do. Instead, they can influence body composition — reducing fat mass while potentially increasing lean mass. The net change in scale weight may be modest, but the underlying shift in body composition can be meaningful for certain research objectives.
| Peptide | Avg Weight Loss | Mechanism Class | Approval Status | Approx Cost/Mo | Requires Rx? |
|---|---|---|---|---|---|
| Tirzepatide | ~20–22% | GLP-1 + GIP dual agonist | FDA Approved (Zepbound) | $199–$499 (telehealth); $900+ brand | Yes |
| Retatrutide | ~24% (Phase 2) | GLP-1 + GIP + glucagon triple | Phase 3 (not approved) | ~$160–$320 (research) | No (research only) |
| Semaglutide | ~15–17% | GLP-1 agonist | FDA Approved (Wegovy) | $149–$399 (telehealth); $800+ brand | Yes |
| AOD-9604 | Unclear (failed Phase 3) | HGH fragment 176–191 | Not approved (TGA food additive) | ~$50–$150 (research) | No (research only) |
| CJC-1295 + Ipamorelin | Body composition shift | GHRH + GHRP → ↑GH | Not approved | ~$50–$100 (research) | No (research only) |
| Sermorelin | Body composition shift | GHRH analogue → ↑GH | Not approved (was FDA approved, withdrawn) | ~$50–$100 (research) | No (research only) |
| Hexarelin | Body composition shift | GHRP → ↑↑GH (highest potency) | Not approved (Phase 2 cardiac) | ~$30–$60 (research) | No (research only) |
For the two FDA-approved compounds (semaglutide and tirzepatide), there are two distinct markets: supervised medical programs and unregulated research peptides. Understanding the difference matters for both safety and legal reasons.
Direct cost comparison for a standard 30-day research period at typical doses and current pricing.
| Approach | Peptide | Typical Monthly Cost | Evidence Strength |
|---|---|---|---|
| Brand-name pharmaceutical | Wegovy / Zepbound | $800–$1,200 | ★★★★★ |
| Telehealth compounded | Semaglutide / Tirzepatide | $149–$499 | ★★★★★ |
| Research peptide (GLP-1) | Semaglutide / Tirzepatide | $100–$250 | ★★★★★ (same molecule, unregulated source) |
| Research peptide (triple agonist) | Retatrutide | $160–$320 | ★★★★☆ (Phase 2 data excellent) |
| Research peptide (GH stack) | CJC-1295 + Ipamorelin | $50–$100 | ★★★☆☆ (body composition, not weight) |
| Research peptide (GH fragment) | AOD-9604 | $50–$120 | ★★☆☆☆ (human data disappointing) |
Tirzepatide and semaglutide have the strongest clinical evidence — both have completed large Phase 3 trials and received FDA approval. Tirzepatide slightly outperforms semaglutide in average weight loss (~20–22% vs ~15–17%). Retatrutide shows even more promising Phase 2 data (~24%) but Phase 3 results are pending. AOD-9604 and GH peptides have significantly weaker evidence for weight loss specifically.
This is a research question that's being actively explored. The combination is theoretically interesting: GLP-1 agonists drive caloric deficit and weight loss, but some of the weight lost can be lean mass; GH peptides may help preserve or increase lean mass during caloric restriction. Early research protocols exploring this combination do exist, but this approach requires medical supervision given the complexity of interacting metabolic pathways. It's not appropriate for self-administration without physician oversight.
The gap between animal and human results for AOD-9604 is significant and not fully explained. Possible factors include: pharmacokinetic differences (how the peptide is processed in humans vs. rodents), dose-response differences, different baseline metabolic states, or simply that the animal models overstated the translational potential. This phenomenon — promising animal data that doesn't translate to human trials — is unfortunately common in metabolic research. The human trial data is what matters, and for weight loss, AOD-9604 did not demonstrate sufficient efficacy.
GLP-1 receptor agonists reduce appetite through multiple pathways: they slow gastric emptying (food stays in the stomach longer, maintaining fullness), stimulate insulin secretion while suppressing glucagon (reducing blood sugar spikes that trigger hunger), and act directly on the hypothalamus and brainstem — areas that regulate appetite and reward signaling. The CNS effects of semaglutide and tirzepatide include reducing the desire for high-calorie foods specifically, beyond just general appetite reduction, which may explain some of their remarkable efficacy.
The chemical sequence is identical — semaglutide is semaglutide. However, pharmaceutical semaglutide (Ozempic/Wegovy) is manufactured under FDA-regulated GMP conditions with strict purity, concentration accuracy, and sterility standards. Research peptides are produced without equivalent oversight, and quality can vary significantly between suppliers and even between batches. Additionally, pharmaceutical semaglutide uses a specific formulation with excipients designed for safe human injection. Research peptides are lyophilized powder that must be reconstituted. The gap between research and pharmaceutical grade is meaningful when it comes to human safety.