Muscle Growth Guide

Peptides for Muscle Growth and Recovery

The muscle-growth peptide conversation splits cleanly in two: compounds that amplify the growth-hormone axis, and compounds that accelerate soft-tissue recovery between training. The best-documented stacks combine one from each lane.

The growth-hormone axis: two receptors, two peptide classes

Growth hormone release from the pituitary is regulated by two separate receptor systems. GHRH analogs activate the GHRH receptor. GHRPs (growth-hormone-releasing peptides) activate the ghrelin receptor. Because these are two distinct pathways, activating both at once produces a larger GH pulse than either alone. This is the mechanistic reason behind the canonical "GHRP + GHRH" stack design.

The GHRP side: ipamorelin, GHRP-2, GHRP-6, hexarelin

Ipamorelin

The most selective of the group. Research reports strong GH release with minimal cortisol or prolactin impact — this is the "clean" reputation ipamorelin carries in comparative studies. Short half-life (~2 hours) supports pulsed dosing.

GHRP-2

Older, still potent. More HPA-axis engagement than ipamorelin — cortisol and prolactin elevation are noticeable at research doses. Benchmark compound in the literature.

GHRP-6

Strongest appetite-stimulation profile in the class — useful if hunger is an endpoint, counterproductive if it isn't.

Hexarelin

Most potent per-mg and the only GHRP with well-documented direct cardiac-tissue effects. More HPA-axis impact than ipamorelin.

The GHRH side: CJC-1295, tesamorelin, sermorelin

CJC-1295 (No DAC and with DAC)

GHRH (1-29) analog. The "No DAC" version has a half-life in hours — suited to multi-daily pulsed protocols. The "with DAC" version includes an albumin-binding modification that extends half-life to days, for sustained-level research.

Tesamorelin

Stabilized GHRH (1-44) analog — closer to native GHRH than CJC-1295. Daily-dose research profile, well documented in visceral-adiposity models.

Sermorelin

GHRH (1-29) without stabilizing modifications. Shortest half-life of the three, which some researchers prefer because it better mimics natural GHRH pulsatility.

The canonical stack: ipamorelin + CJC-1295

This is the combination that dominates the growth-axis research literature. Ipamorelin drives the ghrelin-receptor pulse, CJC-1295 drives the GHRH receptor pulse, and timing them together produces stronger GH release than either alone. Pre-blended vials are available so you don't need to reconstitute two vials separately.

IGF-1 LR3: direct downstream

GH from the pituitary signals the liver to produce IGF-1, which drives many of the anabolic effects attributed to the growth axis. IGF-1 LR3 is a modified IGF-1 variant with a longer half-life, letting researchers study IGF-1 signaling directly without going through the GH axis. Smaller vial (1 mg) because the working doses are lower.

Repair peptides: BPC-157 and TB-500

Training creates microtrauma; recovery sets the pace of progress. BPC-157 and TB-500 are the two most-studied repair peptides and show up in virtually every serious training-peptide protocol.

BPC-157

Drives angiogenesis at injury sites via the VEGFR2 pathway. Enormous rodent-model literature covering tendon, ligament, muscle, and gut tissue. Unusual among peptides for being orally stable.

TB-500

Fragment of Thymosin Beta-4. Promotes cellular migration via actin sequestration. Reported half-life is unusually long for a research peptide (days, not hours).

The combined repair blend

Pre-blended BPC-157 + TB-500 vials (10 mg and 20 mg total mass) are the standard way to run combined-repair research. Different arms of the repair pathway, co-lyophilized.

MOTS-c and mitochondrial support

MOTS-c is a mitochondrial-derived peptide studied in exercise-response and insulin-sensitivity research. Included here because it shows up in some serious performance-oriented stacks alongside SS-31 (cardiolipin-binding, mitochondrial membrane support) and NAD+ (sirtuin substrate).