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ToolsCompareDS5 vs Follistatin 315

DS5 vs Follistatin 315

Side-by-side comparison of key properties, dosing, and research.

Sleep Optimization
DS5
Anabolic & IGF
Follistatin 315
Summary
DS5 is a synthetic variant of the delta sleep-inducing peptide (DSIP), a nonapeptide originally isolated from rabbit cerebrospinal fluid during slow-wave sleep. Like DSIP, DS5 is explored for sleep optimization, stress modulation, and circadian rhythm normalization, with proposed improvements in potency or stability over the parent molecule.
Follistatin 315 is a splice variant isoform of follistatin produced by alternative mRNA processing. Unlike Follistatin 344 which is tethered to cell surfaces via heparan sulfate proteoglycans, FST-315 circulates freely in the bloodstream and has broader systemic distribution. It is the predominant circulating form and exerts systemic myostatin inhibition as well as FSH suppression, making it relevant to both muscle growth and reproductive endocrinology.
Half-Life
Estimated 30-60 minutes (peptide degradation)
~3–5 hours (longer systemic circulation vs FST-344)
Admin Route
Subcutaneous, Intranasal (research)
SubQ, IM
Research
Typical Dose
200-500 mcg per dose
No established human dosing protocol
Frequency
Once nightly
Research use only
Key Benefits
  • Promotes delta-wave (deep) sleep and improves sleep quality
  • May reduce sleep onset latency
  • HPA axis modulation for stress reduction
  • Non-addictive sleep support without tolerance development
  • Potential circadian rhythm normalization
  • Explored for insomnia, chronic stress, and PTSD-related sleep disturbance
  • Systemic myostatin inhibition for whole-body muscle growth
  • Freely circulating — broader tissue distribution than FST-344
  • Strong FSH-suppressive activity useful in certain hormonal protocols
  • Potential for greater anabolic effect across multiple muscle groups simultaneously
  • May be more relevant to reproductive endocrinology applications
  • Studied in gene therapy approaches for muscular dystrophy
Side Effects
  • Generally well-tolerated in research subjects
  • Possible morning grogginess at higher doses
  • Mild blood pressure fluctuations reported with DSIP
  • Limited human safety data for DS5 specifically
  • Systemic FSH suppression — significant concern for fertility
  • Greater potential for off-target effects vs FST-344 due to systemic distribution
  • Limited human safety data
  • Potential cardiac hypertrophy with prolonged high-dose exposure
Stacks With