Leuprolide vs Follistatin 315
Side-by-side comparison of key properties, dosing, and research.
Sexual Health & Libido
LeuprolideAnabolic & IGF
Follistatin 315- Summary
- Leuprolide is a synthetic GnRH superagonist that, with continuous administration, paradoxically suppresses LH and FSH through receptor desensitization — the opposite effect of pulsatile GnRH. Used medically for prostate cancer, endometriosis, and precocious puberty. In men's health, short-duration use for PCT and testosterone suppression rebound.
- 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
- ~3 hours (SC/IM), but depot formulations last 1–12 months
- ~3–5 hours (longer systemic circulation vs FST-344)
- Admin Route
- SubQ, IM
- SubQ, IM
- Research
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- Typical Dose
- 7.5 mg monthly, 22.5 mg 3-monthly, or 45 mg 6-monthly
- No established human dosing protocol
- Frequency
- Per depot schedule
- Research use only
- Key Benefits
- Medical: reduces testosterone in prostate cancer
- Medical: suppresses estrogen in endometriosis and uterine fibroids
- Medical: delays precocious puberty
- Research: testosterone rebound effect after short course
- Transgender care: hormone suppression in adolescents
- Research: hormonal re-sensitization protocols
- 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
- Hot flashes (with testosterone suppression)
- Decreased libido and erectile dysfunction
- Initial testosterone flare (first 1–2 weeks)
- Bone density loss with long-term use
- +3 more
- 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
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