CalcMyPeptide
Growth HormoneAlso known as: GRF 1-29, Geref

Sermorelin

Sermorelin (GRF 1-29) acts as the fundamental bioidentical analog of naturally occurring Growth Hormone-Releasing Hormone (GHRH). Originally developed as an FDA-approved diagnostic agent (Geref), it has become the bedrock of clinical anti-aging endocrinology. Unlike synthetic secretagogues (like GHRPs) that force unnatural spikes via the ghrelin pathway, Sermorelin exclusively orchestrates physiological, pulsatile Growth Hormone release. It is typically prescribed to safely restore youthful IGF-1 baseline levels, drastically improve slow-wave sleep architecture, and accelerate lean tissue recovery without the side effects of exogenous hGH therapy.

Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Moderate2 peer-reviewed citations

Quick Stats

Half-Life~11-12 minutes (IV); ~20-30 minutes (SC)
Dose Range200-300 mcg/day
Frequency1× daily (before bed)
Vial Sizes2 mg, 5 mg, 9 mg
BioavailabilitySubcutaneous injection
Year Developed1990

Scientific Data

Molecular Formula
C149H246N44O42S1
Molecular Weight
3357.93 g/mol
CAS Number
PubChem ID
Developer
Wyeth-Ayerst Laboratories

Mechanism of Action

Sermorelin (GRF 1-29) is a bioidentical analog of natural Growth Hormone Releasing Hormone (GHRH), consisting of the first 29 amino acids of the 44-amino-acid GHRH peptide. These 29 amino acids contain the full biological activity of the complete molecule.

Sermorelin stimulates pituitary somatotroph cells to produce and release growth hormone in a pulsatile, physiological pattern. Unlike exogenous HGH administration, Sermorelin preserves the negative feedback loop — the body still regulates GH output, making supraphysiological levels unlikely. This makes it the safest long-term GH-enhancing option in clinical medicine. FDA-approved as Geref for diagnostic use.

Source: PMID: 9677584

Background & History

Sermorelin (GHRH 1-29 NH₂) is the first 29 amino acids of endogenous GHRH and was the first GHRH analog to receive FDA approval (1997, as Geref, for pediatric GH deficiency). It was developed by researchers at Salk Institute and commercialized by Serono. Unlike CJC-1295 no-DAC with its four protective substitutions, sermorelin is the unmodified sequence and degrades faster (~10-20 min half-life). It was the gold standard for GH stimulation testing before GHRH analogs with better stability were developed.

Research Use Cases

  • Adult GH deficiency: anti-aging and body composition
  • Pediatric growth failure diagnosis and treatment (historical FDA use)
  • Mild GH stimulation protocols with lower side effect profile
  • Sleep improvement and recovery enhancement

Dosing Protocol

Typical Dose200-300 mcg/day
Frequency1× daily (before bed)
Half-Life~10-20 minutes
Common Vial Sizes2 mg, 5 mg, 9 mg

Dosing Protocols

Starting / Clinical

Dose
200 - 300 mcg
Frequency
Nightly before bed (SC)
Note: Standard clinical dose. Inject on an empty stomach (1+ hours after last meal) to maximize the GH pulse.

Standard Stack

Dose
250 mcg Sermorelin + 200 mcg Ipamorelin
Frequency
Nightly before bed (SC)
Note: Most popular GHRH + GHRP stack. Sermorelin amplifies pulse amplitude, Ipamorelin initiates the pulse. Combined GH output 2-5x either alone.

Body-Weight Dosing Reference

Estimated doses extrapolated from the published research range of 200300 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.

WeightLowTargetHigh
120 lb(54 kg)154 mcg193 mcg231 mcg
140 lb(63 kg)180 mcg225 mcg270 mcg
160 lb(73 kg)209 mcg261 mcg313 mcg
180 lb(82 kg)234 mcg293 mcg351 mcg
200 lb(91 kg)260 mcg325 mcg390 mcg
220 lb(100 kg)286 mcg357 mcg429 mcg
250 lb(113 kg)323 mcg404 mcg484 mcg

💉 For exact syringe units based on your vial concentration, use the Sermorelin Reconstitution Calculator →

Administration

Route
Subcutaneous injection
Timing
Before bed on an empty stomach (no food 1+ hours prior).
Fasting Required?
Yes — inject on an empty stomach

Expected Timeline

Week 1-4
Improved sleep quality. Vivid dreams are common (GH pulse during REM). Mild injection site reactions.
Month 1-3
Enhanced recovery, improved body composition, skin quality improvements begin.
Month 3-6
Peak benefits — sustained lean mass improvements, fat loss, improved IGF-1 levels.

Who Is It For?

GH Optimization / Anti-Aging

High

FDA-approved with decades of clinical use. Preserves the pituitary feedback loop unlike direct HGH.

Body Composition

Moderate

Improves lean mass and fat distribution over 3-6 months of consistent use.

Sleep Quality

Moderate

Amplifies the natural nocturnal GH pulse, improving deep sleep and recovery.

Reconstitution Example

Vial
5 mg
Water
2.5 mL
Concentration
2 mg/mL
Per Unit (100u syringe)
20 mcg
Dose of 200 mcg = 10 units on a 100-unit insulin syringe

Safety & Considerations

FDA-approved (Geref) with decades of clinical safety data. Common side effects: injection site flushing and mild headache. Preserves pituitary feedback — far safer than exogenous HGH for long-term use.

Regulatory & Legal Status

FDA Status (US)
Research Only

Former FDA approval withdrawn; available in US via licensed compounding pharmacies

WADA Status (2026)
Prohibited (S2)

Competitive athletes subject to anti-doping controls should not use Sermorelin.

Classification

Compounded Drug (Rx)

US Compounding: Available via licensed pharmacy Rx

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Interactions & Contraindications

Same GH-class interactions as other GHRH analogs: monitor blood glucose, avoid with active cancer. Glucocorticoids blunt GH response.

Synergies & Common Stacks

Sermorelin + Ipamorelin provides GHRH+GHRP synergy similar to Mod GRF + Ipamorelin but with slightly shorter action. Popular combination in anti-aging wellness clinics.

Sermorelin vs. Tesamorelin

AttributeSermorelinTesamorelin
FDA StatusNot FDA-approved (was revoked)FDA-approved (Egrifta® — HIV lipodystrophy)
Half-Life~11–13 minutes~26 minutes (longer-acting)
PotencyModerate GH stimulationStronger — more potent GHRH analog
Best ForGeneral GH/IGF-1 anti-aging protocolVisceral fat reduction (clinical + wellness)
WADA StatusProhibited (S2)Prohibited (S2)
AvailabilityCompounded pharmacy (Rx)Branded Rx + compounded

Verdict: Tesamorelin is the more potent and clinically validated GHRH analog with FDA approval for lipodystrophy. Sermorelin is more widely compounded and used for general anti-aging GH optimization at lower cost.

Dosing Quick Reference

Sermorelin— Dosing Guide
Dose Range
200-300 mcg/day
Half-Life
~10-20 minutes
Frequency
1× daily (before bed)
Route
Subcutaneous
2 mg vial5 mg vial9 mg vial
💧 2.5 mL BAC water📐 2 mg/mL concentration💉 20 mcg/unit (100u syringe)
Growth Hormonecalcmypeptide.com

Frequently Asked Questions

Why is Sermorelin preferred over HGH?
Sermorelin stimulates your own pituitary to release GH naturally, preserving the feedback loop. Exogenous HGH suppresses your natural production. Sermorelin is considered safer for long-term use and does not cause acromegaly risk.
What is the best time to inject Sermorelin?
Before bed on an empty stomach — no food for 1+ hours. This aligns with the natural nocturnal GH pulse and maximizes the synergy between the injection and circadian rhythm.
Can Sermorelin be combined with Ipamorelin?
Yes — Sermorelin + Ipamorelin is the most popular GHRH + GHRP stack. Sermorelin amplifies GH pulse amplitude while Ipamorelin initiates the pulse, producing 2-5× more GH than either alone.

References

  1. Walker RF "Sermorelin: a better approach to management of adult-onset GH insufficiency?".” Clinical Interventions in Aging (2006). PMID: 18046879

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