Mechanism

How it works

Myostatin binds to activin type II receptors (ActRIIA and ActRIIB) on muscle cells, triggering phosphorylation of SMAD2/3 transcription factors via ALK4/5, which suppresses the expression of genes required for muscle protein synthesis and myogenesis. It also downregulates IGF-1/Akt/mTOR signaling, reducing anabolic drive in skeletal muscle. Loss-of-function mutations in MSTN—observed in double-muscled cattle, whippets, and rare human cases—produce dramatic hypermuscular phenotypes, validating its role as a muscle growth brake.

Reported in research

Benefits

Inhibition of myostatin signaling can substantially increase skeletal muscle mass and fiber hypertrophy
May improve muscle strength and functional capacity in conditions involving muscle wasting (sarcopenia, cachexia, DMD)
Potential improvement in insulin sensitivity and metabolic rate via increased lean mass
Possible benefits for bone density through crosstalk with osteoblast signaling pathways

Context, not a prescription

Dosing

Typical range: Research context only; no established human dosing protocol. Anti-myostatin agents (e.g., follistatin peptides) studied at microgram-range doses in animal models. (Subcutaneous, Intramuscular)
Cycle length: Variable; animal studies range 2-12 weeks
Half-life: ~3-5 days (estimated for endogenous mature peptide dimer)

Safety

Side effects & contraindications

Possible side effects

Excessive or disproportionate muscle hypertrophy with uncontrolled inhibition
Potential tendon and connective tissue injury risk due to muscle-tendon strength imbalance
Cardiovascular remodeling concerns with long-term suppression (cardiac muscle effects observed in some animal models)
Possible impairment of reproductive function (myostatin expressed in reproductive tissues)
Altered adipose tissue metabolism with unpredictable fat redistribution

Contraindications

Active cardiac conditions or cardiomyopathy (myostatin also regulates cardiac muscle)
Hormone-sensitive cancers (TGF-β pathway modulation may have oncological implications)
Pregnancy or lactation (role in fetal development is not fully characterized)
Existing connective tissue disorders (tendon/ligament injury risk with rapid muscle mass gain)

Research information, not medical advice. Always consult a licensed clinician before considering any peptide.

In depth

Full profile

What it does

Increased skeletal muscle size and strength, potential improvements in body composition (more muscle, less fat), and in some models, improved metabolic health markers.

How it works

Myostatin is like a governor on a car engine — it prevents the engine from running at full power. Remove or disable the governor, and the engine (your muscles) can operate at much higher output. GDF-8 research focuses on understanding and potentially controlling this governor.

GDF-8 circulates in your bloodstream and attaches to receptors on muscle cells, essentially sending a 'stop growing' message. Inhibiting GDF-8 releases this brake, allowing muscles to respond more strongly to exercise and nutrition. The effect is seen most dramatically in animals born without the gene — they are enormously muscular from birth.

What to expect

In animal studies, measurable increases in muscle mass from myostatin inhibition typically become apparent within 2-4 weeks of treatment.

Week 1: In animal research models, initial receptor binding and early suppression of SMAD2/3 signaling. No immediately visible changes.
Weeks 2-4: Measurable increases in muscle fiber cross-sectional area begin in rodent models. Satellite cell activation increases.
Weeks 4-8: Significant gains in muscle mass observed in animal studies. Metabolic improvements may follow as lean mass increases.

Good to know

Only consider in a research context under professional supervision
Monitor cardiovascular function and connective tissue health if studying in animal models

Staying safe

Risk of tendon strain or injury if muscles grow faster than connective tissue adapts
Possible cardiovascular changes due to myostatin's role in heart muscle regulation

Avoid if you have:

Anyone with heart or cardiovascular conditions
Pregnant or breastfeeding individuals
Anyone with active cancer or a history of hormone-sensitive cancers

Overview

Myostatin inhibition results in type II fiber hypertrophy (fast-twitch), increased satellite cell number and activation, upregulation of MyoD and myogenin, enhanced mTORC1 signaling, decreased proteasomal activity in muscle, and secondary improvements in insulin sensitivity. Bone mineral density improvements are observed in some models via crosstalk with BMP signaling. Fat mass reduction occurs secondary to increased basal metabolic rate from elevated lean mass.

How it works

Myostatin functions like a dual-redundant industrial safety interlock system — it operates at both the transcriptional level (SMAD-mediated gene repression) and post-transcriptional level (mTOR pathway suppression), with multiple extracellular decoy receptors serving as additional failsafes. Inhibiting myostatin requires overcoming all these redundant layers, much like bypassing multiple interlocked circuit breakers simultaneously.

Circulating myostatin exists in a latent complex with its N-terminal propeptide and LTBP-3 on fibrillin microfibrils. Proteolytic activation (via BMP-1/tolloid metalloproteinases) releases the mature dimer into the active pool. Mature myostatin binds ActRIIB with high affinity (Kd ~10 nM), and the resulting signaling cascade modulates both myoblast proliferation (G1 arrest via p21 upregulation) and differentiation (MyoD/myogenin suppression). In muscle fibers, it promotes proteasomal degradation via the ubiquitin-proteasome system. Systemic inhibition via anti-ActRIIB antibodies (e.g., ACE-031) showed robust muscle hypertrophy but also off-target effects on bone and vascular telangiectasia in clinical trials, highlighting the pleiotropic role of this pathway.

Onset & timeline

Peak receptor occupancy with exogenous anti-myostatin agents occurs within hours of administration. SMAD2/3 dephosphorylation is measurable within 24-48 hours. Downstream mRNA changes in atrophy markers (MuRF1, MAFbx) occur within 48-72 hours. Histological evidence of satellite cell activation and myofiber hypertrophy in rodent models is detectable at 7-14 days.

Days 1-3: Ligand-receptor binding achieved with peak plasma concentrations. ActRIIB receptor occupancy drives measurable reduction in pSMAD2/3 levels in myocytes. Downregulation of MuRF1 and MAFbx mRNA begins within 48 hours in rodent models.
Weeks 1-2: Satellite cell activation and proliferation increases. MyoD/myogenin transcription upregulated. Net protein synthesis shifts positive. Early histological evidence of type II fiber cross-sectional area increase in murine studies. mTORC1/S6K1 phosphorylation enhanced.
Weeks 2-8: Progressive and dose-dependent skeletal muscle hypertrophy in animal models, sometimes reaching 30-60% above controls with complete inhibition. Secondary metabolic improvements emerge. Potential connective tissue stress accumulates. In longer-term studies, cardiac mass changes become measurable. Clinical trial data with stamulumab (MYO-029) showed modest non-significant trends in adult muscular dystrophy patients, underscoring translational challenges.

Getting the most from it

Use highly specific anti-myostatin propeptide or monoclonal approaches rather than broad ActRIIB inhibition to minimize off-target BMP pathway effects
Implement progressive resistance training to direct hypertrophic stimulus and reduce connective tissue injury risk
Monitor cardiac function (echocardiography) during prolonged inhibition in animal research protocols
Combine with collagen-supporting agents (e.g., BPC-157, Vitamin C) to mitigate tendon-muscle mismatch risk

Common side effects

Tendinopathy risk due to muscle-tendon mechanical mismatch during rapid hypertrophy phase
Cardiac remodeling — myostatin regulates cardiomyocyte size; inhibition may cause cardiac hypertrophy with unclear functional consequences
Hepatic enzyme elevations observed in some clinical anti-myostatin antibody trials

Mechanism of action

GDF-8/Myostatin signals as a homodimeric ligand through a canonical TGF-β receptor complex. Binding to activin receptor type IIB (ActRIIB) recruits and transphosphorylates the type I co-receptor ALK4 or ALK5, which subsequently phosphorylates receptor-regulated SMADs (pSMAD2/3). The pSMAD2/3 complex associates with SMAD4 and translocates to the nucleus, where it represses MyoD, myogenin, and follistatin expression while activating atrophy-associated ubiquitin ligases (MuRF1, MAFbx/Atrogin-1). Simultaneously, myostatin suppresses Akt/mTOR/p70S6K anabolic signaling via PTEN upregulation and IRS-1 suppression. Myostatin is also regulated extracellularly by its propeptide (MSTN-N), LTBP-3, GASP-1, follistatin, and follistatin-like 3 (FSTL3), providing multiple pharmacological inhibition targets.

Circulating myostatin exists in a latent complex with its N-terminal propeptide and LTBP-3 on fibrillin microfibrils. Proteolytic activation (via BMP-1/tolloid metalloproteinases) releases the mature dimer into the active pool. Mature myostatin binds ActRIIB with high affinity (Kd ~10 nM), and the resulting signaling cascade modulates both myoblast proliferation (G1 arrest via p21 upregulation) and differentiation (MyoD/myogenin suppression). In muscle fibers, it promotes proteasomal degradation via the ubiquitin-proteasome system. Systemic inhibition via anti-ActRIIB antibodies (e.g., ACE-031) showed robust muscle hypertrophy but also off-target effects on bone and vascular telangiectasia in clinical trials, highlighting the pleiotropic role of this pathway.

Pharmacodynamics

Peak receptor occupancy with exogenous anti-myostatin agents occurs within hours of administration. SMAD2/3 dephosphorylation is measurable within 24-48 hours. Downstream mRNA changes in atrophy markers (MuRF1, MAFbx) occur within 48-72 hours. Histological evidence of satellite cell activation and myofiber hypertrophy in rodent models is detectable at 7-14 days.

Myostatin inhibition results in type II fiber hypertrophy (fast-twitch), increased satellite cell number and activation, upregulation of MyoD and myogenin, enhanced mTORC1 signaling, decreased proteasomal activity in muscle, and secondary improvements in insulin sensitivity. Bone mineral density improvements are observed in some models via crosstalk with BMP signaling. Fat mass reduction occurs secondary to increased basal metabolic rate from elevated lean mass.

Timeline

Days 1-3: Ligand-receptor binding achieved with peak plasma concentrations. ActRIIB receptor occupancy drives measurable reduction in pSMAD2/3 levels in myocytes. Downregulation of MuRF1 and MAFbx mRNA begins within 48 hours in rodent models.
Weeks 1-2: Satellite cell activation and proliferation increases. MyoD/myogenin transcription upregulated. Net protein synthesis shifts positive. Early histological evidence of type II fiber cross-sectional area increase in murine studies. mTORC1/S6K1 phosphorylation enhanced.
Weeks 2-8: Progressive and dose-dependent skeletal muscle hypertrophy in animal models, sometimes reaching 30-60% above controls with complete inhibition. Secondary metabolic improvements emerge. Potential connective tissue stress accumulates. In longer-term studies, cardiac mass changes become measurable. Clinical trial data with stamulumab (MYO-029) showed modest non-significant trends in adult muscular dystrophy patients, underscoring translational challenges.

Comparisons

GDF-8 Inhibition (research) — effectiveness High (animal); Moderate (human trials), safety Caution, cost $$$, High complexity to use
Follistatin-344 — effectiveness High (animal); limited human data, safety Caution, cost $$$, High complexity to use
IGF-1 LR3 — effectiveness High, safety Moderate, cost $$$, Medium to use

Adverse effects

Common:

Tendinopathy risk due to muscle-tendon mechanical mismatch during rapid hypertrophy phase
Cardiac remodeling — myostatin regulates cardiomyocyte size; inhibition may cause cardiac hypertrophy with unclear functional consequences
Hepatic enzyme elevations observed in some clinical anti-myostatin antibody trials

Rare:

Epistaxis and telangiectasia observed with ActRIIB-targeting agents in clinical trials (ACE-031 Phase II), attributed to BMP9/10 pathway co-inhibition — incidence ~20% at therapeutic doses in that trial
Reproductive axis suppression possible due to myostatin expression in Sertoli cells and ovarian follicles

Contraindications & risk mitigation

Contraindicated in:

Hypertrophic cardiomyopathy or any cardiomyopathy — myostatin's cardioprotective role is complex and poorly understood
Hereditary hemorrhagic telangiectasia or vascular dysplasia — BMP9/10 co-inhibition risk with broad-spectrum ActRII blockers
Individuals on immunosuppressants — TGF-β/SMAD pathway modulation has immunoregulatory implications
Solid tumor patients — TGF-β signaling has context-dependent tumor suppressive and metastatic roles

Use highly specific anti-myostatin propeptide or monoclonal approaches rather than broad ActRIIB inhibition to minimize off-target BMP pathway effects
Implement progressive resistance training to direct hypertrophic stimulus and reduce connective tissue injury risk
Monitor cardiac function (echocardiography) during prolonged inhibition in animal research protocols
Combine with collagen-supporting agents (e.g., BPC-157, Vitamin C) to mitigate tendon-muscle mismatch risk

Qué hace

Increased skeletal muscle size and strength, potential improvements in body composition (more muscle, less fat), and in some models, improved metabolic health markers.

Cómo funciona

Myostatin is like a governor on a car engine — it prevents the engine from running at full power. Remove or disable the governor, and the engine (your muscles) can operate at much higher output. GDF-8 research focuses on understanding and potentially controlling this governor.

GDF-8 circulates in your bloodstream and attaches to receptors on muscle cells, essentially sending a 'stop growing' message. Inhibiting GDF-8 releases this brake, allowing muscles to respond more strongly to exercise and nutrition. The effect is seen most dramatically in animals born without the gene — they are enormously muscular from birth.

Qué esperar

In animal studies, measurable increases in muscle mass from myostatin inhibition typically become apparent within 2-4 weeks of treatment.

Week 1: In animal research models, initial receptor binding and early suppression of SMAD2/3 signaling. No immediately visible changes.
Weeks 2-4: Measurable increases in muscle fiber cross-sectional area begin in rodent models. Satellite cell activation increases.
Weeks 4-8: Significant gains in muscle mass observed in animal studies. Metabolic improvements may follow as lean mass increases.

Bueno saber

Only consider in a research context under professional supervision
Monitor cardiovascular function and connective tissue health if studying in animal models

Manteniéndose seguro

Risk of tendon strain or injury if muscles grow faster than connective tissue adapts
Possible cardiovascular changes due to myostatin's role in heart muscle regulation

Evitar si tienes:

Anyone with heart or cardiovascular conditions
Pregnant or breastfeeding individuals
Anyone with active cancer or a history of hormone-sensitive cancers

Descripción general

Myostatin inhibition results in type II fiber hypertrophy (fast-twitch), increased satellite cell number and activation, upregulation of MyoD and myogenin, enhanced mTORC1 signaling, decreased proteasomal activity in muscle, and secondary improvements in insulin sensitivity. Bone mineral density improvements are observed in some models via crosstalk with BMP signaling. Fat mass reduction occurs secondary to increased basal metabolic rate from elevated lean mass.

Cómo funciona

Myostatin functions like a dual-redundant industrial safety interlock system — it operates at both the transcriptional level (SMAD-mediated gene repression) and post-transcriptional level (mTOR pathway suppression), with multiple extracellular decoy receptors serving as additional failsafes. Inhibiting myostatin requires overcoming all these redundant layers, much like bypassing multiple interlocked circuit breakers simultaneously.

Circulating myostatin exists in a latent complex with its N-terminal propeptide and LTBP-3 on fibrillin microfibrils. Proteolytic activation (via BMP-1/tolloid metalloproteinases) releases the mature dimer into the active pool. Mature myostatin binds ActRIIB with high affinity (Kd ~10 nM), and the resulting signaling cascade modulates both myoblast proliferation (G1 arrest via p21 upregulation) and differentiation (MyoD/myogenin suppression). In muscle fibers, it promotes proteasomal degradation via the ubiquitin-proteasome system. Systemic inhibition via anti-ActRIIB antibodies (e.g., ACE-031) showed robust muscle hypertrophy but also off-target effects on bone and vascular telangiectasia in clinical trials, highlighting the pleiotropic role of this pathway.

Inicio y cronología

Peak receptor occupancy with exogenous anti-myostatin agents occurs within hours of administration. SMAD2/3 dephosphorylation is measurable within 24-48 hours. Downstream mRNA changes in atrophy markers (MuRF1, MAFbx) occur within 48-72 hours. Histological evidence of satellite cell activation and myofiber hypertrophy in rodent models is detectable at 7-14 days.

Days 1-3: Ligand-receptor binding achieved with peak plasma concentrations. ActRIIB receptor occupancy drives measurable reduction in pSMAD2/3 levels in myocytes. Downregulation of MuRF1 and MAFbx mRNA begins within 48 hours in rodent models.
Weeks 1-2: Satellite cell activation and proliferation increases. MyoD/myogenin transcription upregulated. Net protein synthesis shifts positive. Early histological evidence of type II fiber cross-sectional area increase in murine studies. mTORC1/S6K1 phosphorylation enhanced.
Weeks 2-8: Progressive and dose-dependent skeletal muscle hypertrophy in animal models, sometimes reaching 30-60% above controls with complete inhibition. Secondary metabolic improvements emerge. Potential connective tissue stress accumulates. In longer-term studies, cardiac mass changes become measurable. Clinical trial data with stamulumab (MYO-029) showed modest non-significant trends in adult muscular dystrophy patients, underscoring translational challenges.

Cómo aprovecharlo al máximo

Use highly specific anti-myostatin propeptide or monoclonal approaches rather than broad ActRIIB inhibition to minimize off-target BMP pathway effects
Implement progressive resistance training to direct hypertrophic stimulus and reduce connective tissue injury risk
Monitor cardiac function (echocardiography) during prolonged inhibition in animal research protocols
Combine with collagen-supporting agents (e.g., BPC-157, Vitamin C) to mitigate tendon-muscle mismatch risk

Efectos secundarios comunes

Tendinopathy risk due to muscle-tendon mechanical mismatch during rapid hypertrophy phase
Cardiac remodeling — myostatin regulates cardiomyocyte size; inhibition may cause cardiac hypertrophy with unclear functional consequences
Hepatic enzyme elevations observed in some clinical anti-myostatin antibody trials

Mecanismo de acción

GDF-8/Myostatin signals as a homodimeric ligand through a canonical TGF-β receptor complex. Binding to activin receptor type IIB (ActRIIB) recruits and transphosphorylates the type I co-receptor ALK4 or ALK5, which subsequently phosphorylates receptor-regulated SMADs (pSMAD2/3). The pSMAD2/3 complex associates with SMAD4 and translocates to the nucleus, where it represses MyoD, myogenin, and follistatin expression while activating atrophy-associated ubiquitin ligases (MuRF1, MAFbx/Atrogin-1). Simultaneously, myostatin suppresses Akt/mTOR/p70S6K anabolic signaling via PTEN upregulation and IRS-1 suppression. Myostatin is also regulated extracellularly by its propeptide (MSTN-N), LTBP-3, GASP-1, follistatin, and follistatin-like 3 (FSTL3), providing multiple pharmacological inhibition targets.

Circulating myostatin exists in a latent complex with its N-terminal propeptide and LTBP-3 on fibrillin microfibrils. Proteolytic activation (via BMP-1/tolloid metalloproteinases) releases the mature dimer into the active pool. Mature myostatin binds ActRIIB with high affinity (Kd ~10 nM), and the resulting signaling cascade modulates both myoblast proliferation (G1 arrest via p21 upregulation) and differentiation (MyoD/myogenin suppression). In muscle fibers, it promotes proteasomal degradation via the ubiquitin-proteasome system. Systemic inhibition via anti-ActRIIB antibodies (e.g., ACE-031) showed robust muscle hypertrophy but also off-target effects on bone and vascular telangiectasia in clinical trials, highlighting the pleiotropic role of this pathway.

Farmacodinamia

Peak receptor occupancy with exogenous anti-myostatin agents occurs within hours of administration. SMAD2/3 dephosphorylation is measurable within 24-48 hours. Downstream mRNA changes in atrophy markers (MuRF1, MAFbx) occur within 48-72 hours. Histological evidence of satellite cell activation and myofiber hypertrophy in rodent models is detectable at 7-14 days.

Myostatin inhibition results in type II fiber hypertrophy (fast-twitch), increased satellite cell number and activation, upregulation of MyoD and myogenin, enhanced mTORC1 signaling, decreased proteasomal activity in muscle, and secondary improvements in insulin sensitivity. Bone mineral density improvements are observed in some models via crosstalk with BMP signaling. Fat mass reduction occurs secondary to increased basal metabolic rate from elevated lean mass.

Cronología

Days 1-3: Ligand-receptor binding achieved with peak plasma concentrations. ActRIIB receptor occupancy drives measurable reduction in pSMAD2/3 levels in myocytes. Downregulation of MuRF1 and MAFbx mRNA begins within 48 hours in rodent models.
Weeks 1-2: Satellite cell activation and proliferation increases. MyoD/myogenin transcription upregulated. Net protein synthesis shifts positive. Early histological evidence of type II fiber cross-sectional area increase in murine studies. mTORC1/S6K1 phosphorylation enhanced.
Weeks 2-8: Progressive and dose-dependent skeletal muscle hypertrophy in animal models, sometimes reaching 30-60% above controls with complete inhibition. Secondary metabolic improvements emerge. Potential connective tissue stress accumulates. In longer-term studies, cardiac mass changes become measurable. Clinical trial data with stamulumab (MYO-029) showed modest non-significant trends in adult muscular dystrophy patients, underscoring translational challenges.

Comparaciones

GDF-8 Inhibition (research) — efectividad High (animal); Moderate (human trials), seguridad Caution, costo $$$, High complexity de usar
Follistatin-344 — efectividad High (animal); limited human data, seguridad Caution, costo $$$, High complexity de usar
IGF-1 LR3 — efectividad High, seguridad Moderate, costo $$$, Medium de usar

Efectos adversos

Comunes:

Tendinopathy risk due to muscle-tendon mechanical mismatch during rapid hypertrophy phase
Cardiac remodeling — myostatin regulates cardiomyocyte size; inhibition may cause cardiac hypertrophy with unclear functional consequences
Hepatic enzyme elevations observed in some clinical anti-myostatin antibody trials

Raros:

Epistaxis and telangiectasia observed with ActRIIB-targeting agents in clinical trials (ACE-031 Phase II), attributed to BMP9/10 pathway co-inhibition — incidence ~20% at therapeutic doses in that trial
Reproductive axis suppression possible due to myostatin expression in Sertoli cells and ovarian follicles

Contraindicaciones y mitigación de riesgos

Contraindicado en:

Hypertrophic cardiomyopathy or any cardiomyopathy — myostatin's cardioprotective role is complex and poorly understood
Hereditary hemorrhagic telangiectasia or vascular dysplasia — BMP9/10 co-inhibition risk with broad-spectrum ActRII blockers
Individuals on immunosuppressants — TGF-β/SMAD pathway modulation has immunoregulatory implications
Solid tumor patients — TGF-β signaling has context-dependent tumor suppressive and metastatic roles

Use highly specific anti-myostatin propeptide or monoclonal approaches rather than broad ActRIIB inhibition to minimize off-target BMP pathway effects
Implement progressive resistance training to direct hypertrophic stimulus and reduce connective tissue injury risk
Monitor cardiac function (echocardiography) during prolonged inhibition in animal research protocols
Combine with collagen-supporting agents (e.g., BPC-157, Vitamin C) to mitigate tendon-muscle mismatch risk

Reference data

Specifications

Molecular formula: C₁₁₄H₁₇₈N₃₂O₃₄S (mature monomer approximate)
Molecular weight: ~25 kDa (mature homodimer, ~12.5 kDa per monomer)
Half-life: ~3-5 days (estimated for endogenous mature peptide dimer)
Route: Subcutaneous, Intramuscular
Cycle length: Variable; animal studies range 2-12 weeks
Storage: Store lyophilized peptide at -20°C. After reconstitution with bacteriostatic water, store at 2-8°C and use within 28 days. Avoid repeated freeze-thaw cycles. Protect from light.
Legal status: Not approved for human therapeutic use by FDA or EMA. GDF-8 inhibitors are classified as research compounds. Anti-myostatin antibodies (e.g., stamulumab) have been investigated in clinical trials but none are currently approved. Prohibited in sport by WADA under the category of gene doping and peptide hormones.

FAQ

Common questions

What distinguishes targeting myostatin propeptide vs. ActRIIB for inhibition?

Anti-myostatin propeptide strategies (e.g., recombinant propeptide, peptibodies) selectively neutralize mature GDF-8 without affecting other ActRII ligands like activins, BMP9, or BMP10. ActRIIB-targeted agents (e.g., ACE-031, bimagrumab) provide greater hypertrophic potency but co-inhibit these pathways, explaining the vascular and reproductive side effects seen in clinical trials. Target selectivity is the key pharmacological trade-off in this space.

What is the clinical trial landscape for myostatin inhibitors?

Multiple approaches have reached human trials: stamulumab (MYO-029, Wyeth) anti-myostatin antibody for muscular dystrophy (Phase II, 2008 — did not meet efficacy endpoints); domagrozumab (PF-06252616, Pfizer) for Duchenne MD (Phase II, 2019 — failed primary endpoint); apitegromab (Scholar Rock) — Phase III ongoing for SMA; bimagrumab (ActRIIA/B inhibitor, Novartis) — showed positive results in sarcopenia and obesity trials. None are currently approved. The translational gap from animal to human is notable.

What is the evidence level?

This compound is classified as Animal data. Most data comes from preclinical animal studies. Human clinical trial evidence is limited or absent.

Research

Research & sources

Animal data

Current evidence for GDF-8 (Myostatin) is rated as Animal data. Research is based primarily on animal models.

1. McPherron AC et al. Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member (1997) — Nature, 387:83-90. doi:10.1038/387083a0
2. Schuelke M et al. Myostatin mutation associated with gross muscle hypertrophy in a child (2004) — N Engl J Med, 350:2682-2688. doi:10.1056/NEJMoa040933
3. Wagner KR et al. A phase I/II trial of MYO-029 in adult subjects with muscular dystrophy (2008) — Ann Neurol, 63(5):561-571. doi:10.1002/ana.21338
4. Latres E et al. Activin A more prominently regulates muscle mass in primates than does GDF8 (2017) — Nature Communications, 8:15153. doi:10.1038/ncomms15153
5. Bimagrumab vs Optimized Standard of Care for Treatment of Sarcopenia in Community-Dwelling Older Adults (2021) — JAMA Network Open, 4(10):e2033604. doi:10.1001/jamanetworkopen.2020.33604

Explore

Often discussed alongside

Follistatin-344 · growth IGF-1 LR3 · growth BPC-157 · healing TB-500 · healing