GHRH Axis Pharmacology Review
Reviews GHRH axis pharmacology including agonism with Sermorelin and antagonism for AML therapy. Establishes the mechanistic foundation for modern clinical use.
[1]Sermorelin (GRF 1-29 NH2) is a synthetic 29-amino-acid peptide representing the active fragment of native growth hormone-releasing hormone (GHRH). It was the original synthetic GHRH analog and historically held FDA approval as Geref for the diagnosis and treatment of pediatric growth hormone deficiency. The FDA-approved product was discontinued in 2008 for commercial reasons, not safety concerns. Sermorelin remains widely available through compounding pharmacies and is one of the most commonly used GHRH analogs in functional and regenerative medicine practice.
At a glance
- Type
- Synthetic 29-amino-acid peptide (GRF 1-29 NH2), the active fragment of native GHRH
- Mechanism
- Identical mechanism to native GHRH; short half-life of 10 to 20 minutes
- Regulatory
- Historically FDA approved as Geref for pediatric GH deficiency; discontinued 2008 for commercial reasons, not safety concerns
- Availability
- Compounding pharmacies
- Route
- Subcutaneous
- WADA
- Banned for competitive athletes
What the research supports
Sermorelin's evidence base spans historical FDA approval, modern GHRH axis pharmacology reviews, and continuing class-level positioning.
GHRH Antagonist and Longevity
GHRH antagonist work in the SAMP8 mouse model explored longevity effects, suggesting complex GHRH/GH/IGF-1 axis effects on aging biology.
[2]Historical FDA Approval (Geref)
Sermorelin held FDA approval as Geref for pediatric GH deficiency. Product discontinued 2008 for commercial reasons, not safety concerns.
GHRH Receptor Mechanism
Identical mechanism to native GHRH. Short half-life of 10 to 20 minutes produces a brief physiologic pulse aligned with natural GH secretion patterns.
Summary of key findings
Original GHRH Analog
Historically FDA approved as Geref. One of the best documented safety profiles in the peptide space, with decades of clinical use supporting its track record.
Short Half-Life Requires Frequent Dosing
10 to 20 minute half-life produces transient pulses. Longer-acting analogs such as CJC-1295 and Tesamorelin have largely supplanted Sermorelin in modern practice.
Always Pair with a GHRP
Ipamorelin is the standard combination partner. Sermorelin monotherapy is less effective than combination protocols and should rarely be used alone.
Lower-Cost Alternative
Accessible, established peptide for cost-sensitive patients or those preferring the historically approved option over newer analogs.
Dosing guide
From published protocols. Licensed provider supervision assumed throughout.
- Subcutaneous Standard
- 200 to 500 mcg SC daily, AM empty stomach or PM pre-bed.
- Higher Dose Protocol
- 500 to 1000 mcg SC daily, sometimes divided into 2 doses.
- Combination with Ipamorelin
- Sermorelin 200 to 300 mcg plus Ipamorelin 200 to 300 mcg SC, 1 to 2 times daily.
- Cycling
- Run continuously 3 to 6 months with periodic IGF-1 monitoring; or cycle 8 to 12 weeks on with 4 week breaks.
Vial reference
Units are for a U-100 insulin syringe (100 units = 1 mL), computed from the vial concentration.
| Vial | Dose range | Units per dose | Frequency | Notes |
|---|---|---|---|---|
| Sermorelin 5 mg / 1 mL | 200 to 500 mcg | 4 to 10 units | Daily | 0.05 mg per unit. Fasted 2 hours before first meal or before bed or split. |
| Sermorelin 10 mg / 2 mL | 200 to 500 mcg | 4 to 10 units | Daily | 0.05 mg per unit. AM empty stomach or PM pre-bed. |
Pre-bedtime dosing aligns with the natural circadian GH pulse for optimal physiologic effect.
Reference ranges as published in the source protocol document, not a prescription. To work out the draw for a specific vial and dose, use the Peptide Calculator.
Bottom line
Sermorelin is the original GHRH analog with the same mechanism as CJC-1295 but a much shorter half-life. Historically FDA approved as Geref for pediatric GH deficiency; the brand was discontinued in 2008 for commercial reasons, not safety. In modern practice, CJC-1295 No DAC has largely replaced Sermorelin for most indications because of the longer half-life and cleaner pulse pharmacology. However, Sermorelin remains widely used and clinically effective. The historical FDA-approved status gives Sermorelin one of the best documented safety profiles in the peptide space. Position it as the more accessible, lower-cost alternative to CJC-1295 with a similar safety profile. Always pair with a GHRP (Ipamorelin is the standard choice). Monitor IGF-1 every 3 to 6 months. WADA banned for competitive athletes.
GHRH Analog Foundation
Original synthetic GHRH analog with decades of clinical use and a well-established safety record.
Cost-Accessible Option
Lower cost than CJC-1295 with a similar safety profile, making it ideal for cost-sensitive patients.
Combination Workhorse
Pair with Ipamorelin for synergistic GH pulse amplification. Monotherapy is not recommended.
References
Citations sourced from PubMed and verified against the PubMed record.
- 1Costoya et al., 2024 GHRH Axis Pharmacology and AML Antagonist Review
- 2Banks et al., 2010 GHRH Antagonist Effects on Aging Biology
- 3Walker, 2006 Sermorelin Clinical Use in Adult GH Decline Review
- 4Sermorelin and Aging Brain Effects ReviewCitation under review
Regulatory status, cautions and contraindications
Contraindications
Active malignancy: relative contraindication. Pregnancy and lactation: contraindicated. Hypothyroidism: ensure adequate thyroid replacement before starting. WADA banned for competitive athletes.
Monitoring Requirements
Monitor IGF-1 every 3 to 6 months during active therapy. Ongoing medical supervision is essential throughout treatment. Licensed healthcare provider oversight required for all protocols. Individual health assessment prior to initiation is mandatory.
Legal disclaimer
These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
This peptide overview is for informational purposes only and does not constitute medical advice. The information provided here is not intended to diagnose, treat, cure, or prevent any disease. Peptide therapies should only be used under the guidance of a licensed healthcare provider, who can assess individual health needs and determine appropriate dosing and administration.
Always consult your healthcare provider before starting any new treatment, as misuse or improper dosing may lead to adverse effects. The efficacy and safety of peptide therapies have not been fully established in all cases, and ongoing medical supervision is essential.