Follistatin 315 vs PNC-27
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Immune Support
PNC-27- Summary
- 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.
- PNC-27 is a synthetic peptide derived from the p53 tumor suppressor protein, containing both an HDM2-binding domain and a transmembrane penetratin sequence. It selectively kills cancer cells by binding MDM2/HDM2 overexpressed on the plasma membrane of malignant cells, inducing membranolysis without harming normal cells.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Not well established; estimated minutes to hours
- Admin Route
- SubQ, IM
- Intravenous (research), Intraperitoneal (research)
- Research
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- Typical Dose
- No established human dosing protocol
- Not established for humans; research doses vary by cell line and model
- Frequency
- Research use only
- Not established for human use
- Key Benefits
- 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
- Selective cytotoxicity against cancer cells overexpressing HDM2/MDM2
- Spares normal cells lacking surface HDM2 expression
- Membranolytic mechanism bypasses intracellular resistance pathways
- Demonstrated activity against breast, pancreatic, leukemia, and melanoma cell lines
- Potential for combination with conventional chemotherapy
- Novel non-genotoxic anticancer mechanism
- Side Effects
- 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
- Limited human clinical data; largely in vitro and animal studies
- Potential immunogenic reactions (foreign peptide)
- Systemic toxicity at high doses not well characterized
- Unknown interactions with current chemotherapy agents
- Stacks With
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