Head to head
Follistatin against ACE-031
Two ways to block the same pathway, a natural inhibitor delivered largely by gene therapy and a receptor decoy that reached trials. ACE-031's trials in muscular dystrophy were halted over vascular safety signals, which is the most useful fact about this class.
Column A
FollistatinFollistatin (myostatin/activin antagonist)
A natural protein that blocks myostatin and activin, studied largely through gene therapy for muscle growth and muscular dystrophy.
Column B
ACE-031ACE-031 (soluble activin receptor type IIB)
A myostatin/activin decoy studied for muscular dystrophy whose trials were halted over vascular safety signals.
Side by side, on the facts we can check
| Attribute | Follistatin | ACE-031 |
|---|---|---|
| Category | Muscle & Performance | Muscle & Performance |
| FDA status | Not FDA-approved; investigational (gene therapy) | Not FDA-approved; development halted on safety grounds |
| Half-life | Short (protein) | Days (fusion protein) |
| Molecular weight | ~35,000 Da | ~78,000 Da |
| Mechanism | Sequesters myostatin and activin, releasing their inhibition of muscle growth and promoting muscle fiber size. | Binds and neutralizes myostatin and activin before they can signal, releasing their inhibition of muscle growth. |
| Human studies cited | 2 | 2 |
| Legal status, US | Not approved; research use only | Not approved; research use only |
Frequently asked questions
What is the difference between Follistatin and ACE-031?
Follistatin: A natural protein that blocks myostatin and activin, studied largely through gene therapy for muscle growth and muscular dystrophy. ACE-031: A myostatin/activin decoy studied for muscular dystrophy whose trials were halted over vascular safety signals.
Which has stronger research evidence, Follistatin or ACE-031?
This database does not grade compounds. It counts what was run in people: 2 of the 4 studies cited on the Follistatin profile were human work, against 2 of 2 for ACE-031. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Follistatin and ACE-031 FDA-approved?
Follistatin: Not FDA-approved; investigational (gene therapy). ACE-031: Not FDA-approved; development halted on safety grounds.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.