--- title: "Trevogrumab | PepTracker Pro" description: "Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass." lang: en json-ld: | [ { "@context": "https://schema.org", "@type": "Organization", "name": "PepTracker Pro", "url": "https://peptrackerpro.com", "logo": "https://peptrackerpro.com/favicon.png", "description": "Evidence-based educational resource dedicated to improving peptide research literacy.", "contactPoint": { "@type": "ContactPoint", "email": "hello@peptrackerpro.com", "contactType": "customer support" }, "sameAs": [] }, { "@context": "https://schema.org", "@type": "MedicalWebPage", "name": "Trevogrumab", "description": "Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass.", "url": "https://peptrackerpro.com/peptides/trevogrumab", "lastReviewed": "2026-07-17", "reviewedBy": { "@type": "Organization", "name": "PepTracker Pro Research Team", "url": "https://peptrackerpro.com" }, "isPartOf": { "@type": "WebSite", "name": "PepTracker Pro", "url": "https://peptrackerpro.com" } }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://peptrackerpro.com" }, { "@type": "ListItem", "position": 2, "name": "Peptides", "item": "https://peptrackerpro.com/peptides" }, { "@type": "ListItem", "position": 3, "name": "Trevogrumab", "item": "https://peptrackerpro.com/peptides/trevogrumab" } ] }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "People concerned about losing muscle while taking GLP-1 weight-loss drugs?", "acceptedAnswer": { "@type": "Answer", "text": "Trevogrumab is a research peptide studied in preclinical models. Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass." } }, { "@type": "Question", "name": "Those following the emerging class of muscle-preserving add-ons to obesity therapy?", "acceptedAnswer": { "@type": "Answer", "text": "Trevogrumab is a research peptide studied in preclinical models. Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass." } }, { "@type": "Question", "name": "Individuals comparing myostatin- and activin-pathway inhibitors (trevogrumab, apitegromab, bimagrumab, taldefgrobep alfa)?", "acceptedAnswer": { "@type": "Answer", "text": "Trevogrumab is a research peptide studied in preclinical models. Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass." } } ] } ] --- [Skip to main content](#main) **Educational information only.** This site does not provide medical advice. [Read full disclaimer](/disclaimer) [PepTracker Pro](/) [Home](/)[Peptides](/peptides)[Compare](/compare)[Glossary](/glossary)[Blog](/blog)[Calculators](/calculators)[Start Here](/start) [Open the App](https://app.peptrackerpro.com) [Peptides](/peptides)/ Trevogrumab **Research-only content.** This page is for educational purposes and does not constitute medical advice. [Read full disclaimer →](/research-disclaimer) # Trevogrumab Medium Evidence Trevogrumab (REGN1033) is an investigational fully human anti-myostatin (anti-GDF8) monoclonal antibody from Regeneron being tested as a lean-mass-sparing add-on to semaglutide in the Phase 2 COURAGE obesity trial; adding it to semaglutide prevented roughly half of the ~33% of GLP-1-induced weight loss that normally comes from muscle, and the semaglutide + trevogrumab + garetosmab triplet reached 13.4% weight loss at 26 weeks with only ~7.4% of that loss from lean mass. Aliases Trevogrumab +5 more Evidence Medium Evidence Last Updated 2026-07-17 Reading Time 4 min ## Table of Contents 1. [What It Is](#what-it-is) 2. [Regulatory Status](#regulatory-status) 3. [Why Researchers Study It](#why-researchers-study) 4. [Proposed Mechanisms](#proposed-mechanisms) 5. [Evidence Snapshot](#evidence-snapshot) 6. [Commonly Discussed Benefits](#benefits) 7. [Safety & Cautions](#safety) 8. [Comparisons](#comparisons) 9. [Calculator Tools](#calculator) 10. [Citations](#citations) ## What It Is Trevogrumab (REGN1033) is an investigational fully human monoclonal antibody that binds and neutralizes myostatin (growth differentiation factor 8, GDF-8), a circulating protein that acts as a brake on skeletal-muscle growth. By blocking myostatin, trevogrumab aims to preserve or increase lean muscle mass. Regeneron originally advanced the antibody for age-related sarcopenia, but its most prominent current use is as a muscle-preserving partner for GLP-1 obesity drugs. A recognized limitation of highly effective incretin weight-loss therapy is that a substantial share of the weight lost is lean (muscle) mass rather than fat - roughly a third of semaglutide-induced weight loss in the COURAGE program came from lean tissue. Losing muscle alongside fat is a concern for long-term metabolic health, physical function, and healthy aging, and it has spurred a wave of muscle-directed add-ons including the myostatin-precursor antibody apitegromab, the ActRII-blocking antibody bimagrumab, and the myostatin/activin decoy taldefgrobep alfa. Trevogrumab is Regeneron's entry in this class. The Phase 2 COURAGE trial (NCT06299098) is a large randomized, double-blind study of ~999 participants evaluating trevogrumab - with or without garetosmab (an anti-activin A antibody) - added to semaglutide for obesity, using two consecutive 26-week periods (weight loss then weight maintenance). Complete 26-week results, presented as a late-breaking oral session at the European Association for the Study of Diabetes (EASD) meeting in September 2025, showed that semaglutide alone reduced lean body mass by ~6.5% from baseline, versus ~3.3% with semaglutide + trevogrumab 200 mg and ~3.8% with trevogrumab 400 mg - roughly halving the lean-mass loss. The semaglutide + trevogrumab + garetosmab triplet produced the greatest total weight loss (~13.4%) while limiting the share of weight lost as lean mass to about 7.4%, and adding garetosmab enhanced fat-mass reduction by ~27.3% versus semaglutide alone while preserving over 80% of lean body mass. Tolerability tracked with the added biology: adverse-event discontinuations were 4.6% for semaglutide alone, 4.7% for semaglutide + trevogrumab 200 mg, and 10.6% for trevogrumab 400 mg, with the activin-A-blocking garetosmab arms carrying a higher burden of side effects. The COURAGE trial is expected to complete in late 2026. Trevogrumab is investigational and not approved for any indication. Also known as: Trevogrumab, REGN1033, REGN-1033, SAR391786, anti-GDF8 monoclonal antibody (Regeneron), anti-myostatin antibody REGN1033 ## Regulatory Status Investigational - not approved Trevogrumab is in Phase 2 development for muscle preservation during GLP-1-induced weight loss (COURAGE trial, NCT06299098), combined with semaglutide and, in some arms, garetosmab. Complete 26-week results were presented at EASD in September 2025. Not approved for any indication. Effective: September 2025 [View FDA Source](https://investor.regeneron.com/news-releases/news-release-details/results-phase-2-courage-trial-demonstrating-potential-improve) ## Why Researchers Study It Trevogrumab is central to one of the most active questions in obesity medicine: how to keep GLP-1 weight loss from stripping away muscle. Because roughly a third of semaglutide-induced weight loss came from lean mass in COURAGE, a myostatin-blocking antibody that halves that muscle loss - and, in triplet form with an anti-activin-A antibody, preserves more than 80% of lean mass while deepening fat loss - could meaningfully improve the quality of weight loss, physical function, and long-term metabolic outcomes. It also lets researchers dissect the distinct contributions of the myostatin (GDF-8) and activin A pathways to muscle wasting. ## Proposed Mechanisms - Binds and neutralizes circulating myostatin (GDF-8), releasing its inhibitory brake on skeletal-muscle growth to preserve or increase lean mass - Counteracts the lean-mass loss that accompanies GLP-1-receptor-agonist (semaglutide) weight loss, shifting the composition of weight lost toward fat - In combination with garetosmab (anti-activin A), blocks a second muscle-atrophy signaling pathway, further preserving lean mass and enhancing fat-mass loss - Muscle-directed mechanism complements the appetite- and glucose-regulating action of incretin drugs rather than adding to their GI effects ## Evidence Snapshot Medium Evidence Low Medium High Study Type Model Outcome Link Phase 2 (COURAGE, NCT06299098) - randomized, double-blind, placebo/active-controlled ~999 adults; parts B/C in obesity - semaglutide +/- trevogrumab (200 or 400 mg) +/- garetosmab; two 26-week periods (weight loss, then maintenance) Lean body mass fell ~6.5% with semaglutide alone vs ~3.3% (trevogrumab 200 mg) and ~3.8% (400 mg) added - roughly halving lean-mass loss; ~33% of semaglutide weight loss was lean mass, and trevogrumab prevented about half of it [Source](https://investor.regeneron.com/news-releases/news-release-details/results-phase-2-courage-trial-demonstrating-potential-improve) Phase 2 (COURAGE) - triplet arm, 26-week analysis Semaglutide + trevogrumab + garetosmab (anti-activin A) vs semaglutide alone Triplet reached ~13.4% total weight loss with only ~7.4% of loss from lean mass; garetosmab addition enhanced fat-mass reduction ~27.3% over semaglutide alone while preserving >80% of lean body mass [Source](https://www.patientcareonline.com/view/regeneron-phase-2b-study-shows-antibodies-help-preserve-lean-mass-during-weight-loss-with-semaglutide) Phase 2 (COURAGE) - safety/tolerability, 26 weeks Discontinuations due to adverse events across arms AE-related discontinuation 4.6% (semaglutide alone), 4.7% (semaglutide + trevogrumab 200 mg), 10.6% (trevogrumab 400 mg); garetosmab-containing arms carried a higher side-effect burden [Source](https://www.medscape.com/viewarticle/myostatin-blocker-preserves-muscle-glp-1-treatment-2025a1000qs4) ## Commonly Discussed Benefits [muscle-preservation](/benefits/muscle-preservation)[lean-mass-retention](/benefits/lean-mass-retention)[body-composition](/benefits/body-composition)[Fat Loss](/benefits/fat-loss)[Weight Management](/benefits/weight-management) Researching Trevogrumab ? Track it, set reminders, and keep notes in the free app. [Track in App](https://app.peptrackerpro.com/?add=trevogrumab) ## Safety & Cautions - Investigational - not approved for any indication; Phase 2 COURAGE trial ongoing, expected to complete late 2026 - Data are 26-week results presented at a conference (EASD 2025); full peer-reviewed publication and longer-term outcomes not yet available - Higher trevogrumab dose (400 mg) and garetosmab-containing (anti-activin A) arms showed greater adverse-event and discontinuation burden - Long-term effects of chronic myostatin blockade on muscle strength, function, tendons, and safety are not established - Cross-trial comparisons with other muscle-preserving agents (apitegromab, bimagrumab, taldefgrobep alfa) have significant limitations due to differing designs, GLP-1 partners, and endpoints ## Comparisons See how Trevogrumab compares to related peptides: [Trevogrumab vs Apitegromab](/compare/trevogrumab-vs-apitegromab) [Trevogrumab vs Bimagrumab](/compare/trevogrumab-vs-bimagrumab) [Trevogrumab vs CAP-GDF15](/compare/trevogrumab-vs-cap-gdf15) [Trevogrumab vs Garetosmab](/compare/trevogrumab-vs-garetosmab) [Trevogrumab vs Semaglutide](/compare/trevogrumab-vs-semaglutide) [Trevogrumab vs Sotatercept](/compare/trevogrumab-vs-sotatercept) [Trevogrumab vs Taldefgrobep Alfa](/compare/trevogrumab-vs-taldefgrobep) [Trevogrumab vs Tirzepatide](/compare/trevogrumab-vs-tirzepatide) [Trevogrumab vs WVE-007](/compare/trevogrumab-vs-wve-007) ## Calculator Tools Use our research tools to explore dosing and reconstitution data: [Reconstitution Calculator](/calculators) ## Citations 1. \[1\] Results from Phase 2 COURAGE Trial Demonstrating Potential to Improve Quality of GLP-1 Receptor Agonist-induced Weight Loss by Preserving Lean Mass, Presented at EASD - Regeneron (September 2025) [PubMed](https://investor.regeneron.com/news-releases/news-release-details/results-phase-2-courage-trial-demonstrating-potential-improve) 2. \[2\] Regeneron Phase 2b Study Shows Antibodies Help Preserve Lean Mass During Weight Loss with Semaglutide - Patient Care Online (2025) [PubMed](https://www.patientcareonline.com/view/regeneron-phase-2b-study-shows-antibodies-help-preserve-lean-mass-during-weight-loss-with-semaglutide) 3. \[3\] Myostatin Blocker Preserves Muscle With GLP-1 Treatment - Medscape (2025) [PubMed](https://www.medscape.com/viewarticle/myostatin-blocker-preserves-muscle-glp-1-treatment-2025a1000qs4) 4. \[4\] Regeneron's Semaglutide Plus Trevogrumab Combo Demonstrates Superior Fat Loss with Reduced Muscle Wasting in Obesity Trial - Pharmaceutical Executive (2025) [PubMed](https://www.pharmexec.com/view/regeneron-semaglutide-trevogrumab-demonstrates-superior-fat-loss-reduced-muscle-wasting-obesity-trial) ### Keep researching in the app - Log Trevogrumab to your private tracker - Set a dosing reminder - Compare it side-by-side with your stack [Open PepTracker Pro Free](https://app.peptrackerpro.com/?add=trevogrumab) [Browse more peptides](/peptides) ## Related Peptides ### Apitegromab Low Evidence Apitegromab (SRK-015) is an investigational, fully human IgG4 monoclonal antibody developed by Scholar Rock that inhibits myostatin - the muscle-produced growth factor that limits skeletal-muscle mass - through a novel, muscle-selective mechanism. Rather than neutralizing mature, active myostatin (the approach of earlier failed inhibitors), apitegromab binds only the inactive precursor forms of the protein - promyostatin and latent myostatin - stored locally in muscle, and blocks their proteolytic conversion into the active ligand. Because it spares the closely related growth factors activin A, BMP9/10, and TGF-beta1, it aims to avoid the off-target effects (such as bleeding and vascular changes) that sank broad ActRII-pathway drugs. Apitegromab is the first muscle-targeted therapy to succeed in a pivotal Phase 3 trial in spinal muscular atrophy (SMA): in the 156-patient SAPPHIRE study of nonambulatory Type 2/3 patients aged 2-12 already on an SMN-directed therapy (nusinersen or risdiplam), adding apitegromab (10 or 20 mg/kg IV every 4 weeks) improved motor function by a pooled 1.8 points on the Hammersmith Functional Motor Scale Expanded (HFMSE) versus placebo at 12 months (p=0.019). Scholar Rock's initial Biologics License Application received an FDA Complete Response Letter in September 2025 tied solely to a third-party (Catalent Indiana) fill-finish manufacturing inspection - not to the drug's efficacy or safety - and the company resubmitted the BLA on March 31, 2026, with a PDUFA target action date of September 30, 2026. In parallel, apitegromab produced positive Phase 2 obesity data (EMBRAZE): added to tirzepatide over 24 weeks it preserved about 55% more lean mass (roughly 1.9 kg / 4.2 lb) than tirzepatide alone, positioning myostatin inhibition as a potential lean-mass-sparing partner for GLP-1-based weight loss. [spinal muscular atrophy (SMA) - improved motor function when added to SMN-directed therapy in nonambulatory Type 2/3 patients (investigational; Phase 3 SAPPHIRE positive)]()[muscle strength and motor-scale (HFMSE/RHS) gains via muscle-selective myostatin inhibition]()[lean-mass preservation during GLP-1/GIP (tirzepatide) weight loss (investigational; Phase 2 EMBRAZE positive)]()[potential treatment of facioscapulohumeral muscular dystrophy (FSHD) and other muscle-wasting conditions (preclinical/early clinical)]()+1 more [View Details](/peptides/apitegromab) [\+ Compare](/compare?select=apitegromab)[](https://app.peptrackerpro.com/?add=apitegromab) ### Bimagrumab Medium Evidence An anti-activin type II receptor antibody that promotes fat loss while preserving lean muscle mass, studied in combination with GLP-1 agonists for obesity. [Fat Loss](/benefits/fat-loss)[muscle-preservation](/benefits/muscle-preservation)[Weight Management](/benefits/weight-management)[body-composition](/benefits/body-composition)+1 more [View Details](/peptides/bimagrumab) [\+ Compare](/compare?select=bimagrumab)[](https://app.peptrackerpro.com/?add=bimagrumab) ### CAP-GDF15 Low Evidence A newly discovered 12-amino acid anorexigenic peptide derived from the GDF15 prepropeptide region, representing a novel appetite-suppression pathway. [Appetite Regulation](/benefits/appetite-regulation)[Weight Management](/benefits/weight-management)[Metabolism](/benefits/metabolism) [View Details](/peptides/cap-gdf15) [\+ Compare](/compare?select=cap-gdf15)[](https://app.peptrackerpro.com/?add=cap-gdf15) ### Garetosmab Medium Evidence Garetosmab (REGN2477) is Regeneron's investigational fully human anti-activin A monoclonal antibody. In the Phase 3 OPTIMA trial in adults with the ultra-rare bone disease fibrodysplasia ossificans progressiva (FOP), it cut new heterotopic bone lesions by ~90-94% and reduced new-lesion volume by >99% versus placebo; its BLA was accepted for FDA Priority Review with an August 2026 target action date. The same activin A blockade also makes garetosmab the muscle-preserving partner to trevogrumab and semaglutide in the Phase 2 COURAGE obesity program. [heterotopic-ossification-reduction](/benefits/heterotopic-ossification-reduction)[rare-disease-treatment](/benefits/rare-disease-treatment)[muscle-preservation](/benefits/muscle-preservation)[body-composition](/benefits/body-composition)+1 more [View Details](/peptides/garetosmab) [\+ Compare](/compare?select=garetosmab)[](https://app.peptrackerpro.com/?add=garetosmab) ### Semaglutide High Evidence A GLP-1 receptor agonist FDA-approved for type 2 diabetes and chronic weight management. [Weight Management](/benefits/weight-management)[Appetite Regulation](/benefits/appetite-regulation)[Metabolism](/benefits/metabolism)[Fat Loss](/benefits/fat-loss)+3 more [View Details](/peptides/semaglutide) [\+ Compare](/compare?select=semaglutide)[](https://app.peptrackerpro.com/?add=semaglutide) ### Sotatercept High Evidence Sotatercept (Winrevair, sotatercept-csrk) is Merck's first-in-class activin signaling inhibitor - a recombinant ActRIIA-Fc fusion protein that acts as a ligand trap for activin A, activin B, GDF-8 (myostatin) and GDF-11. It is FDA-approved for adults with pulmonary arterial hypertension (PAH), where it improved 6-minute walk distance by 40.8 meters in the Phase 3 STELLAR trial and, in the Phase 3 ZENITH trial in high-risk patients, cut the composite risk of death, lung transplantation and PAH hospitalization by 76%. An expanded U.S. label reflecting ZENITH was approved on October 27, 2025. [pulmonary-vascular-remodeling](/benefits/pulmonary-vascular-remodeling)[exercise-capacity](/benefits/exercise-capacity)[cardiovascular-support](/benefits/cardiovascular-support)[rare-disease-treatment](/benefits/rare-disease-treatment)+1 more [View Details](/peptides/sotatercept) [\+ Compare](/compare?select=sotatercept)[](https://app.peptrackerpro.com/?add=sotatercept) ### Taldefgrobep Alfa Low Evidence A novel myostatin-activin pathway inhibitor targeting fat reduction and lean mass gain, with Phase 2 results in obesity expected H2 2026. [Fat Loss](/benefits/fat-loss)[muscle-preservation](/benefits/muscle-preservation)[Muscle Growth](/benefits/muscle-growth)[body-composition](/benefits/body-composition)+1 more [View Details](/peptides/taldefgrobep) [\+ Compare](/compare?select=taldefgrobep)[](https://app.peptrackerpro.com/?add=taldefgrobep) ### Tirzepatide High Evidence A dual GIP/GLP-1 receptor agonist FDA-approved for type 2 diabetes, weight management, and MASH with liver fibrosis. [Weight Management](/benefits/weight-management)[Appetite Regulation](/benefits/appetite-regulation)[Metabolism](/benefits/metabolism)[Fat Loss](/benefits/fat-loss)+1 more [View Details](/peptides/tirzepatide) [\+ Compare](/compare?select=tirzepatide)[](https://app.peptrackerpro.com/?add=tirzepatide) ### WVE-007 Low Evidence WVE-007 is Wave Life Sciences' investigational GalNAc-conjugated siRNA that silences the liver gene INHBE to lower the hepatokine Activin E, aiming to produce muscle-sparing fat loss. In the Phase 1 INLIGHT trial a single subcutaneous dose reduced visceral and total fat while preserving or increasing lean mass, with durable target knockdown that could support once- or twice-yearly dosing. [Weight Management](/benefits/weight-management)[Metabolism](/benefits/metabolism)[Fat Loss](/benefits/fat-loss)[muscle-preservation](/benefits/muscle-preservation) [View Details](/peptides/wve-007) [\+ Compare](/compare?select=wve-007)[](https://app.peptrackerpro.com/?add=wve-007) [PepTracker Pro](/) Educational peptide information and research tracking tools. 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