Follistatin 344 (FS344) — Human dosage only (what's actually in clinical studies)
Quickstart Highlights
Compound (Human clinical form): rAAV1.CMV.huFS344 (AAV1‑mediated follistatin FS344 gene transfer)
Route used in trials: Intramuscular (IM) injections into targeted muscles
How dosing is expressed: vector genomes per kilogram (vg/kg) (not mg)
Human trial doses reported: 6 × 10¹¹ vg/kg and 1.2 × 10¹² vg/kg (BMD cohorts); 6 × 10¹¹ vg/kg (sIBM)
Key point: FS344 human dosing is gene‑therapy dosing, not a peptide "mcg/mg" protocol.
Dosing & Reconstitution
Standard Approach (Human trials)
Standard Approach (Human trials)
Human studies administer a total body‑weight–based vector dose (vg/kg) divided across multiple IM injection sites in the target muscles.
Becker Muscular Dystrophy (BMD) trial structure:
- Cohort 1: 6 × 10¹¹ vg/kg total (delivered as multiple IM injections into quadriceps bilaterally)
- Cohort 2: 1.2 × 10¹² vg/kg total (same injection pattern; higher dose cohort)
Sporadic Inclusion Body Myositis (sIBM) trial:
- 6 × 10¹¹ vg/kg delivered to quadriceps of both legs (IM)
Supplies Needed
For the website page, we keep this high‑level only (no procedural detail):
- Clinical‑grade vector preparation (trial setting)
- Standard sterile IM administration supplies (clinical setting)
(Trial administration is done by trained clinical staff; protocols are not "DIY.")
Protocol Overview
Goal of human FS344 trials: increase local muscle performance/volume via sustained follistatin expression in injected muscle groups.
How the human protocols are structured:
- One‑time gene transfer dosing (not daily injections)
- IM injection sites distributed through target muscles
- Follow‑up over months for functional endpoints
Dosing Protocol (Human clinical data only)
Protocol A — Becker Muscular Dystrophy (Dose‑escalation cohorts)
- Low cohort: 6 × 10¹¹ vg/kg total (IM; bilateral quadriceps)
- High cohort: 1.2 × 10¹² vg/kg total (IM; bilateral quadriceps)
Protocol B — Sporadic Inclusion Body Myositis
- 6 × 10¹¹ vg/kg (IM; quadriceps both legs)
Protocol C — Duchenne Muscular Dystrophy (trial registry dosing plan)
- Proposed: 2.4 × 10¹² vg/kg total divided among multiple muscle groups (trial design listing)
Storage Instructions
For website education:
- Storage/handling is determined by clinical vector handling requirements (cold‑chain controlled).
- Not comparable to standard "peptide vial" storage.
Important Notes
- FS344 "human dosing" in literature = AAV gene transfer dosing (vg/kg).
- If someone is quoting a "mcg/day" or "mg/week" FS344 protocol, that is generally not coming from human clinical trials (and should not be presented as standardized human dosing).
- This is not FDA‑approved as a commercial therapy; use is within controlled research/clinical protocols.
How This Works
Follistatin binds/inhibits myostatin/activin‑family signaling, which can shift muscle growth regulation pathways. Human trials attempt to achieve localized, sustained expression in injected muscles via AAV delivery.
Benefits & Side Effects (Human trial framing)
What trials measured (examples):
- Functional outcomes (e.g., 6‑minute walk test)
- Muscle performance measures
- Safety/tolerability and follow‑up monitoring
Because this is gene transfer, safety considerations are evaluated differently than for short‑acting peptides.
Lifestyle Factors
In at least one human protocol, an exercise regimen was included alongside gene transfer—important when interpreting outcomes.
Injection Technique
For this page, best practice is to avoid "how‑to" injection technique instructions, because human FS344 dosing in the literature is clinical gene therapy delivered by professionals under protocol.
Administration is performed by trained clinical staff; not a self‑administration protocol.
Recommended Source
From an educational/compliance standpoint:
- Reference published clinical trials and ClinicalTrials.gov entries for dosing details.
- Avoid presenting non‑trial dosing as "human protocol."
Important Note
This content is for educational purposes only and is not medical advice. FS344 (rAAV1.CMV.huFS344) is for research use only. Not for human consumption. Always consult with qualified professionals before starting any gene‑transfer research protocol.
References
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BMD clinical trial dosing cohorts — 6×10¹¹ vg/kg and 1.2×10¹² vg/kg
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sIBM trial dosing — 6×10¹¹ vg/kg
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DMD trial registry proposed dosing — 2.4×10¹² vg/kg



