Follistatin is the clearest case in this catalogue of a compound whose human dose record cannot be converted into the form it is sold in — because the record is not measured in a mass.
What the registry holds, and what it appears to hold
ClinicalTrials.gov, 21 September 2026:
| Search | Records |
|---|---|
follistatin (all fields) |
80 |
follistatin (intervention) |
15 |
Eighty looks like a substantial literature. Reading the fifteen separates them into two groups that a count cannot distinguish.
Studies that measure follistatin. Serum follistatin-like protein 1 in Behçet's disease. Follistatin levels in metabolically healthy and unhealthy obese individuals. Myostatin, activin A and follistatin in cachexia of head and neck cancers. FGF21 and follistatin after acute endurance exercise. Follistatin in sarcopenia. In these, follistatin is an outcome measure — a thing drawn from a vein and read — and the intervention is atorvastatin, or L-arginine, or omega-3, or exercise, or surgery.
Studies that administer something. Five of them, and every one administers a gene.
The human dose record
| Study | Sponsor | n | Construct | Dose |
|---|---|---|---|---|
| NCT01519349 | Nationwide Children's Hospital | 15 | rAAV1.CMV.huFollistatin344 | 2×10¹¹ vg/kg (single quadriceps), 3×10¹¹ vg/kg per quadriceps, 6×10¹¹ vg/kg per quadriceps |
| NCT02354781 | Jerry R. Mendell, Nationwide Children's | 3 (6 planned) | rAAV1.CMV.huFS344 | 2.4×10¹² vg/kg total, 1.2×10¹² per limb |
| NCT06411366 | Minicircle | 43 | FST344 plasmid | Non-viral plasmid, injectable |
| NCT07285629 | Minicircle | 14 | Klotho + follistatin plasmid | Non-viral plasmid, healthy volunteers |
| NCT07443826 | (recruiting) | 12 | AAV9-follistatin | — |
The unit in the first two rows is vector genomes per kilogram of body weight. It is a count of DNA copies, normalised to the person's mass. It is not micrograms, and there is no exchange rate.
That is the whole finding. A vial of follistatin protein has no human dose precedent to be read against — not a smaller one, not a larger one, not one in a different unit. The record is about a different physical quantity.
What was actually given, and where
The Nationwide Children's phase 1 trial is the founding record. The investigators set out to deliver the follistatin gene (FS344) to thigh muscle in Becker muscular dystrophy and sporadic inclusion body myositis, carried by adeno-associated virus, in the hope of increasing quadriceps size and prolonging walking.
| Cohort | n | Dose | Distribution |
|---|---|---|---|
| 1 | 3 (sIBM only) | 2×10¹¹ vg/kg | One quadriceps, unilateral |
| 2 | 6 (3 sIBM, 3 BMD) | 3×10¹¹ vg/kg per quadriceps | Both quadriceps |
| 3 | 6 (3 sIBM, 3 BMD) | 6×10¹¹ vg/kg per quadriceps | Both quadriceps |
The follow-on study in Duchenne muscular dystrophy went considerably higher — 2.4×10¹² vg/kg total, deliberately spread wider: gluteal muscles, quadriceps and tibialis anterior, at 1.2×10¹² vg/kg per limb, with the number of injections per muscle depending on the size of the patient. Its stated rationale was the safety record and functional improvement in the earlier Becker cohort.
Note the two dimensions in every row that a single number would lose: which muscles, and how many injections. The protein is produced where the gene lands. A gene-transfer dose describes a treated region as much as a quantity.
The commercial plasmid studies are a different platform
The two Minicircle studies use a non-viral plasmid rather than an AAV vector — circular DNA intended, in the sponsor's own description, as a non-permanent and non-heritable method of inducing gene expression, containing the human FST344 gene to express and secrete bioidentical follistatin into circulation.
They are also the largest by enrolment: 43 participants in the phase 1 injectable plasmid study, run at the Global Alliance for Regenerative Medicine, and 14 healthy adult volunteers in the early phase 1 klotho-and-follistatin combination study at the Apeiron Center and the GARM Clinic.
A plasmid dose and an AAV vector-genome dose are not interchangeable figures, and the registry records for the plasmid studies do not state a quantity in a comparable unit. The two platforms sit in the same table above because they are the same compound's human record, not because the numbers can be read across.
The whole human record, counted honestly
By enrolment: 15 + 3 + 43 + 14, with 12 more recruiting. Fewer than a hundred people, across two incompatible delivery platforms, at four centres, with one study still open and using a third vector serotype.
Every one is phase 1 or early phase 1 — the stage at which the question is whether the intervention is tolerated, not whether it works and not what dose to use. Two of the five are at a single US children's hospital in muscular dystrophy; two are from one commercial sponsor in healthy volunteers at offshore clinics.
Nothing in that record establishes a dose, and none of the studies claims to. Stating that plainly is more useful than assembling the numbers into an average.
Method
The ClinicalTrials.gov v2 API was queried on 21 September 2026 for follistatin, both as a general term and as an intervention, and each of the five administering records was opened individually so that its arm descriptions, sponsor, enrolment type and brief summary could be read rather than inferred from structured fields — this site's standing rule since a registry record was found on 20 September that disclaimed itself in its own summary. Enrolment figures are quoted with their type: NCT01519349's 15 and NCT02354781's 3 are actual, the remainder as the registry records them. Related records: the dosage chart grades every compound here by the tier of source behind its figure, how to read a dosing claim sets out why a dose in one unit cannot be converted into another by arithmetic, and peptide sources explained covers what can and cannot be verified about material of this kind. Nothing on this page is a dosing instruction.