PT-141 (Bremelanotide) vs Follistatin 315
Side-by-side comparison of key properties, dosing, and research.
Sexual Health & Libido
PT-141 (Bremelanotide)Anabolic & IGF
Follistatin 315- Summary
- PT-141 (Bremelanotide) is a cyclic peptide melanocortin receptor agonist that enhances sexual desire and arousal through central nervous system mechanisms. It is FDA-approved as Vyleesi for premenopausal women with hypoactive sexual desire disorder (HSDD).
- 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
- 2–3 hours
- ~3–5 hours (longer systemic circulation vs FST-344)
- Admin Route
- SubQ
- SubQ, IM
- Research
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- —
- Typical Dose
- 0.5–1.75 mg
- No established human dosing protocol
- Frequency
- As needed (not daily)
- Research use only
- Key Benefits
- Enhances sexual desire and libido in both men and women
- Improves arousal through central nervous system activation
- Effective for psychological erectile dysfunction
- Works for female sexual arousal disorder
- May improve sexual satisfaction and intensity
- Fast-acting — effects within 45–60 minutes
- FDA-approved for HSDD in premenopausal women
- 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
- Nausea (most common — 40% of users in clinical trials)
- Facial flushing and warmth
- Transient blood pressure changes (typically increase then normalize)
- Headache
- +2 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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