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Category HubUpdated Feb 2026

Muscle Growth Peptides

Growth hormone secretagogues and anabolic peptides for lean mass development. These peptides aim to optimize natural GH production, enhance recovery, and support muscle protein synthesis.

Category Overview

Peptides for muscle growth primarily work through the growth hormone (GH) axis. Growth hormone secretagogues stimulate your pituitary gland to release more GH naturally, which in turn increases IGF-1 levels — both critical for muscle protein synthesis, recovery, and body composition.

Unlike anabolic steroids, GH peptides work within your body's natural feedback loops. Results are more subtle but side effects are generally milder. Most muscle growth peptides are research compounds (not FDA-approved), with tesamorelin being the notable exception.

Important context: No peptide replaces consistent training and nutrition. Peptides may enhance recovery and optimize hormonal environment, but they are not shortcuts to muscle growth. The most impactful factors remain progressive overload training, adequate protein intake (1.6-2.2g/kg/day), sufficient sleep, and caloric surplus.

How GH Secretagogue Peptides Work

The GH axis has two main stimulatory pathways that peptides can target:

GHRH pathway: Growth hormone-releasing hormone tells the pituitary to produce and release GH. CJC-1295 and tesamorelin mimic this pathway. They increase the overall amount of GH available.

Ghrelin/GHS-R pathway: Growth hormone secretagogues like ipamorelin, GHRP-6, and GHRP-2 activate the ghrelin receptor on the pituitary, amplifying GH release pulses. They increase the intensity of GH release.

Combination approach: Using a GHRH analog (CJC-1295) with a GHSR agonist (ipamorelin) together produces synergistic GH release greater than either alone. This "CJC/Ipa" combination is the most popular GH peptide protocol.

All Muscle Growth Peptides

CJC-1295

Growth hormone-releasing hormone (GHRH) analog. Often combined with ipamorelin for synergistic GH release. Available with or without DAC (Drug Affinity Complex) for different half-lives.

Research
Ipamorelin

Selective growth hormone secretagogue that stimulates GH release with minimal cortisol or prolactin increase. One of the most popular GH peptides in clinical practice.

Research
Tesamorelin

FDA-approved GHRH analog for HIV-associated lipodystrophy. Reduces visceral fat and may improve body composition. The only FDA-approved GH secretagogue.

FDA Approved
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MK-677 (Ibutamoren)

Oral growth hormone secretagogue (non-peptide). Increases GH and IGF-1 levels. Convenient oral dosing but concerns about insulin resistance and appetite increase with long-term use.

Research
GHRP-6

Growth hormone-releasing peptide. Potent GH release but causes significant hunger (ghrelin-like activity). Older generation GH peptide largely replaced by ipamorelin.

Research
GHRP-2

More potent GH release than GHRP-6 with less appetite stimulation. Some cortisol and prolactin elevation. Used in research and some clinical settings.

Research
Hexarelin

Most potent GHRP for acute GH release. However, causes significant cortisol and prolactin increase and rapid desensitization with repeated use, limiting practical utility.

Research
Follistatin

Myostatin inhibitor that theoretically removes the brakes on muscle growth. Promising concept but limited human data and significant technical challenges with delivery and dosing.

Research
BPC-157

While primarily a healing peptide, BPC-157 may support muscle recovery and repair after injury, indirectly supporting muscle growth and training capacity.

Research
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IGF-1 LR3

Long-acting insulin-like growth factor 1 variant. Promotes muscle cell hyperplasia (new cell formation). Significant safety concerns including hypoglycemia and potential cancer risk.

Research

Disclaimer: Most muscle growth peptides are research compounds not approved by the FDA for human use. This information is for educational purposes only. Consult a healthcare provider before using any peptide therapy. Do not self-medicate with research chemicals.