Follistatin vs Sermorelin
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Follistatin
Follistatin is a glycoprotein that inhibits myostatin, the protein responsible for limiting muscle growth. By blocking myostatin, follistatin can theoretically allow for increased muscle development beyond natural limits.
Full details →Sermorelin
Sermorelin is a synthetic analog of GHRH consisting of the first 29 amino acids of the natural hormone. It was previously FDA-approved for GH deficiency diagnosis and treatment in children.
Full details →Side-by-Side Comparison
| Aspect | Follistatin | Sermorelin |
|---|---|---|
| Dose Range | 50 mcg–100 mcg | 100 mcg–300 mcg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | 2–4 weeks | 8–12 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | Binds to and neutralizes myostatin and activin, both of which are negative regulators of muscle mass. This removes the natural brake on muscle growth, allowing for enhanced hypertrophy. | Binds to GHRH receptors in the pituitary gland to stimulate natural GH production and release. Maintains the body's natural feedback mechanisms for GH regulation. |
| Typical Dosage | Research protocols typically use 100-300mcg daily, though optimal dosing is not well established. Gene therapy approaches have also been studied. | Typical dosing: 200-500mcg administered once daily, usually before bed. Some protocols use twice daily dosing. |
| Administration | Subcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity. | Subcutaneous injection, preferably at bedtime to work with natural GH release patterns. Can be combined with GHRPs for synergistic effects. |
| Side Effects | Limited human data. Theoretical concerns about effects on other organs where activin signaling is important. | Generally well-tolerated. May cause injection site reactions, headache, flushing, or dizziness. Less side effects than direct GH administration. |
| Best For |
What They Have in Common
Follistatin, Sermorelin are both commonly used for:
Key Differences
Unique to Sermorelin:
Which Has Stronger Evidence?
| Goal | Follistatin | Sermorelin |
|---|---|---|
| Muscle Growth | medium | medium |
Key Studies
Follistatin
- Heart to Heal: Unveiling Follistatin's Potential for Myocardial Regeneration.
Circulation research, 2025
- Fructose and follistatin potentiate acute MASLD during complete hepatic insulin resistance.
Nature communications, 2025
- Follistatin drives neuropathic pain in mice through IGF1R signaling in nociceptive neurons.
Science translational medicine, 2024
Sermorelin
- A potentially effective drug for patients with recurrent glioma: sermorelin.
Annals of translational medicine, 2021
- Sermorelin: a better approach to management of adult-onset growth hormone insufficiency?
Clinical interventions in aging, 2006
- Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency.
BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy, 1999
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