Several peptides have been studied in clinical and preclinical research for their potential effects on metabolism, fat oxidation, and body composition. None are FDA-approved for weight loss. Any use is subject to medical approval by a licensed provider at TelosRX.
This guide reviews five peptides that appear most frequently in metabolic research, what the evidence shows, and what patients typically ask before considering them.
| Peptide | Mechanism | Primary Research Area | Evidence Level |
|---|---|---|---|
| AOD 9604 | GH fragment; lipolysis stimulation | Fat metabolism, body composition | Phase 2 clinical (discontinued) |
| MOTS-c | Mitochondrial-derived; AMPK activation | Insulin sensitivity, metabolic regulation | Preclinical + early human data |
| Tesamorelin | GHRH analog; GH release stimulation | Visceral fat reduction (HIV lipodystrophy) | FDA-approved for specific indication |
| BPC-157 | Gastric pentadecapeptide; tissue repair | GI, musculoskeletal, metabolic support | Primarily preclinical (animal models) |
| GHK-Cu | Copper peptide; regenerative signaling | Skin, tissue remodeling, inflammation | In vitro + limited human data |
1. AOD 9604: The GH Fragment
AOD 9604 is a synthetic fragment of human growth hormone (hGH), specifically amino acids 176–191, engineered to retain the lipolytic properties of GH without the anabolic or insulin-sensitizing effects of the full molecule.
In animal studies, AOD 9604 demonstrated fat-specific effects including increased fat oxidation and reduced adipose tissue accumulation. Human Phase 2 trials in the early 2000s showed some reductions in body weight but were not large enough to reach statistical significance across all endpoints, and development for obesity was discontinued.
AOD 9604 is not FDA-approved for any indication. It is not classified as a Generally Recognized As Safe (GRAS) substance for food or supplement use. It is available in compounded form through licensed providers who determine patient eligibility.
More detail: AOD 9604: HGH Fragment Research Guide
2. MOTS-c: The Mitochondrial Peptide
MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c) is a peptide encoded in mitochondrial DNA and expressed in skeletal muscle. It activates AMPK (AMP-activated protein kinase), a key energy-sensing enzyme involved in glucose uptake, fatty acid oxidation, and metabolic homeostasis.
Preclinical studies have shown MOTS-c improves insulin sensitivity, reduces diet-induced obesity in mouse models, and increases exercise-related metabolic adaptations. A 2023 review in PMC highlighted its role in age-related metabolic decline and its potential as a longevity-related therapeutic target.
Human data remain limited. MOTS-c is not FDA-approved and is available only through compounded preparations subject to provider evaluation.
More detail: MOTS-c: Mitochondrial Peptide and Metabolic Research
3. Tesamorelin: The FDA-Approved GHRH Analog
Tesamorelin is a growth hormone-releasing hormone (GHRH) analog FDA-approved under the brand name Egrifta for reduction of excess abdominal fat in HIV-positive patients with lipodystrophy. It is the only peptide on this list with an approved indication.
Tesamorelin works by stimulating endogenous GH release from the pituitary, which in turn promotes lipolysis in visceral adipose tissue. Clinical trials in HIV lipodystrophy showed statistically significant reductions in visceral adipose tissue (VAT) compared to placebo.
Off-label use in non-HIV populations is being studied for age-related visceral adiposity and metabolic syndrome. Any use outside the approved indication requires provider evaluation and is not FDA-sanctioned for those indications. Compounded tesamorelin is not FDA-approved.
More detail: Tesamorelin: Benefits, Dosage, and Research Guide
4. BPC-157: Systemic Repair Peptide
BPC-157 (Body Protection Compound 157) is a synthetic pentadecapeptide derived from a gastric protein. It has been studied primarily in preclinical models for its effects on tissue repair, GI healing, tendon and ligament recovery, and systemic anti-inflammatory signaling.
Metabolic research in animal models suggests BPC-157 may influence insulin receptor signaling and reduce metabolic disruption associated with high-fat diets, though mechanisms are not fully characterized. There are no completed human clinical trials for BPC-157 in weight loss or metabolic indications.
BPC-157 is not FDA-approved for any indication. The FDA has issued guidance restricting its use in compounded preparations. Provider evaluation is required, and availability may vary by jurisdiction.
More detail: BPC-157: Patient Guide 2026
5. GHK-Cu: Copper Peptide for Regenerative Signaling
GHK-Cu (glycyl-L-histidyl-L-lysine copper complex) is a naturally occurring plasma peptide that declines with age. It has been studied extensively for its effects on wound healing, collagen synthesis, and anti-inflammatory signaling. In vitro research also suggests effects on gene expression pathways related to cellular repair and antioxidant defense.
While GHK-Cu is not primarily a weight-loss peptide, its metabolic interest lies in its anti-inflammatory and regenerative properties that may support tissue remodeling in the context of broader metabolic optimization protocols. Evidence in humans for direct metabolic or weight-related outcomes is limited to observational and in vitro data.
GHK-Cu is not FDA-approved. It is used topically in cosmetic formulations and is available in injectable compounded preparations subject to provider evaluation.
What to Know Before Considering a Metabolic Peptide
Before pursuing any compounded peptide, several factors should be reviewed with a licensed provider:
- Evidence quality: Most peptides have preclinical data; few have robust human RCT evidence for weight-specific outcomes.
- Regulatory status: With the exception of tesamorelin for its approved indication, none of these peptides are FDA-approved for weight loss or metabolic use.
- Compounding compliance: Compounded peptides must be prepared by a licensed pharmacy under federal compounding regulations.
- Individual baseline: Labs, body composition data, and metabolic history inform whether any peptide is appropriate for a specific patient.
- Combination protocols: Some peptides are used alongside GLP-1 agonists or hormone optimization; the appropriateness of any combination is determined by the provider.
A licensed provider at TelosRX can review your metabolic profile and determine whether peptide evaluation is appropriate for your situation.
Frequently Asked Questions
Are peptides effective for weight loss?
Evidence varies significantly by peptide. Tesamorelin has the strongest human trial data for visceral fat reduction, but only in HIV lipodystrophy. AOD 9604 showed early promise in animal and small human studies but did not complete Phase 3 trials for obesity. MOTS-c and GHK-Cu have primarily preclinical data. No peptide on this list is FDA-approved for weight loss in the general population.
Can I use peptides alongside GLP-1 medications?
Some providers use peptides as part of broader metabolic protocols that may include GLP-1 agonists, hormone optimization, or other interventions. Whether this is appropriate for a specific patient depends on individual labs, history, and clinical assessment. Any combination requires provider evaluation and approval.
Is AOD 9604 legal in the United States?
AOD 9604 is not FDA-approved and is not classified as GRAS for supplement use. It is available through compounding pharmacies when prescribed by a licensed provider. Its regulatory status has been subject to FDA guidance in recent years; patients should discuss current availability with their provider.
What is the difference between MOTS-c and regular GH peptides?
MOTS-c is encoded in mitochondrial DNA and works primarily through AMPK activation, distinct from growth hormone secretagogues (like tesamorelin or CJC-1295) which stimulate pituitary GH release. MOTS-c has a unique mechanism tied to cellular energy sensing rather than the GH-IGF-1 axis.
How do I get a peptide evaluation through TelosRX?
TelosRX operates as an online-first, asynchronous telehealth service. You submit your intake information, labs, and health history; a licensed provider reviews your case and determines whether a peptide or other intervention is appropriate. Approval is not guaranteed and depends on individual clinical criteria.
TelosRX is LegitScript-certified. Compounded medications are not FDA-approved and are prepared under federal compounding regulations. Approval is subject to evaluation by a licensed provider; approval is not guaranteed. Individual results vary. TelosRX operates as an online-first, asynchronous telehealth service.
Start your private evaluation at TelosRX.