Mod GRF 1-29 vs Sermorelin
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Mod GRF 1-29
Mod GRF 1-29 (Modified GRF 1-29, also called CJC-1295 without DAC or Tetrasubstituted GRF 1-29) is a modified growth hormone-releasing hormone analog with improved stability over natural GHRH.
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 | Mod GRF 1-29 | Sermorelin |
|---|---|---|
| Dose Range | 100 mcg–200 mcg | 100 mcg–300 mcg |
| Frequency | 3x daily | 1x daily |
| Cycle Length | 8–12 weeks | 8–12 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | Binds to GHRH receptors in the pituitary gland to stimulate growth hormone release. Four amino acid substitutions improve resistance to enzymatic degradation while maintaining biological activity. | 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 | Typical dosing: 100-300mcg administered 2-3 times daily, usually combined with a GHRP like Ipamorelin for synergistic effects. | Typical dosing: 200-500mcg administered once daily, usually before bed. Some protocols use twice daily dosing. |
| Administration | Subcutaneous injection. Best administered on empty stomach. Short half-life (~30 minutes) necessitates multiple daily doses, unlike DAC version. | Subcutaneous injection, preferably at bedtime to work with natural GH release patterns. Can be combined with GHRPs for synergistic effects. |
| Side Effects | Flushing, headache, dizziness, and injection site reactions. Generally well-tolerated. May cause water retention. | 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
Mod GRF 1-29, Sermorelin are both commonly used for:
Which Has Stronger Evidence?
- Muscle Growth: Mod GRF 1-29 has stronger research support.
| Goal | Mod GRF 1-29 | Sermorelin |
|---|---|---|
| Muscle Growth | high | medium |
| Fat Loss | medium | medium |
| Recovery & Healing | medium | medium |
| Sleep Quality | medium | medium |
Key Studies
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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