FS315 vs REGN1033

Head-to-head comparison of FS315 (Follistatin-315 (FS315)) and REGN1033 (Trevogrumab (REGN1033)) — benefits, dosing, side effects, research data, and where to buy.

Research Score

PropertyFS315REGN1033
CategoryMuscle & PerformanceMuscle & Performance
Full NameFollistatin-315 (FS315)Trevogrumab (REGN1033)
Molecular Weight~40 kDa~150 kDa
Half-LifeN/A; depends on construct/delivery~2-3 weeks
Amino Acids315N/A
Typical DoseResearch-only; no standardized human dose100-300 mg SC or equivalent trial dosing
RouteIntramuscular / research expression systemsSubcutaneous / Intravenous
Purity≥98%≥98%
Studies Count9560
Research StatusPre-clinicalClinical

FS315 Benefits

  • activin neutralization
  • muscle growth signaling
  • anti-catabolic support
  • tissue repair modulation

REGN1033 Benefits

  • myostatin blockade
  • lean-mass preservation
  • muscle hypertrophy support
  • catabolic-state countermeasure

FS315 Dosing

Research-only recombinant/protein-expression studies|no standardized clinical dose|route varies by platform

REGN1033 Dosing

SC or IV clinical-trial dosing|repeat every 2-4 weeks|dose escalation by study

FS315 Side Effects

  • off-target endocrine effects
  • immune response risk
  • fluid balance changes

REGN1033 Side Effects

  • injection-site reactions
  • headache
  • fatigue

Research Overview

FS315

Follistatin-315 is a key reference isoform in studies of muscle anabolism and reproductive/endocrine biology. In muscle research, it is relevant because it suppresses activin and can indirectly blunt myostatin pathway output.

REGN1033

Human and animal studies indicate that myostatin neutralization can increase muscle size, though functional gains are often smaller than mass gains. Trevogrumab is part of the broader literature showing that selective myostatin inhibition can alter body composition in clinically meaningful ways.

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Common Stacking Partners

FS315 stacks with:

CreatineVitamin DLeucine

REGN1033 stacks with:

CreatineVitamin DLeucine
follistatinactivin-inhibitormyostatin-pathwayproteinmyostatin-antibodymabslean-massmuscle-growth