315-amino-acid isoform of follistatin glycoprotein (~38 kDa). Extended circulating half-life (~10 days) due to lower heparan sulfate proteoglycan binding compared to FS-288 isoform. Subcutaneous administration.
Follistatin-315 is a growth hormone-related peptide. 315-amino-acid isoform of follistatin glycoprotein (~38 kDa).
With a half-life of ~10 days (240 hours), Follistatin-315 supports less frequent dosing schedules. Administered via SubQ injection, it has a bioavailability of approximately 70% via its primary route.
Extended circulating half-life (~10 days) due to lower heparan sulfate proteoglycan binding compared to FS-288 isoform. Subcutaneous administration. One-compartment model.
Follistatin-315's pharmacological activity involves the following key pathways:
Follistatin-315 interacts with the growth hormone axis to influence GH-related signaling pathways.
| Parameter | Value |
|---|---|
| Half-Life | ~10 days (240 hours) |
| Bioavailability | ~70% |
| Time to Peak | ~12 hours |
| Duration of Activity | ~21 days |
| Routes | Subcutaneous |
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Follistatin-315 is supplied as a lyophilized (freeze-dried) powder and requires reconstitution before use. Common vial sizes: 1 mg, 5 mg.
Collect the Follistatin-315 vial, bacteriostatic water, alcohol swabs, a mixing syringe, and insulin syringes for dosing. Ensure all items are stored properly and unexpired.
Wipe the rubber stopper of both the Follistatin-315 vial and bacteriostatic water vial with alcohol swabs. Allow to air dry for 10 seconds before proceeding.
Draw 1 mL of bacteriostatic water and inject it slowly down the inside wall of the Follistatin-315 vial. Follistatin is a delicate protein — never spray directly onto the lyophilized powder.
Allow the water to dissolve the powder naturally over 2–3 minutes. Gently roll the vial between your palms if needed. Do not shake or agitate, as follistatin can denature easily.
The reconstituted solution should be clear and colorless. If particles or cloudiness persist after gentle swirling, the peptide may have degraded and the vial should not be used.
Store the reconstituted vial upright in the refrigerator at 2–8°C. For a 1 mg vial reconstituted with 1 mL, each 10 units on a 100-unit insulin syringe equals 100 mcg.
1 mg vial + 1 mL bac water = 1,000 mcg/mL. For a 100 mcg dose, draw 10 units on a 100-unit insulin syringe. Use the Milligram reconstitution calculator for custom vial sizes.
Reconstituted Follistatin-315 is stable for up to 14 days refrigerated at 2–8°C. Follistatin is a larger protein and more fragile than smaller peptides — avoid repeated freeze-thaw cycles and excessive agitation.