GH / IGF-1 axis
One of 6 mechanistic pathways to 💪 Build muscle & strength · 14 options
Growth hormone drives IGF-1, and IGF-1 activates PI3K/Akt/mTOR — the central hypertrophy signal. The honest read: GH is excellent for connective tissue, recovery and body composition, and a weaker direct hypertrophic agent than its reputation. Most of what people attribute to it is fluid and glycogen.
IGF-1 is the only honest read on whether a GH protocol is doing anything — GH itself is pulsatile and a single draw is close to meaningless. Track fasting glucose and insulin alongside, because the most predictable cost of this pathway is insulin resistance and it arrives quietly.
IGF-1 (Insulin-like Growth Factor 1)Growth Hormone, SerumFasting InsulinHbA1c (Hemoglobin A1c)🌙 Running GH Peptides or MK-677 covers these in one panel →
What engages this pathway
Ordered by how directly each one acts on the mechanism above — never by how much trial evidence exists. Each links to its full breakdown with dosing, half-life and vendor.
💉 HGH
Exogenous GH. Raises IGF-1 and lean mass reliably, improves recovery and connective-tissue quality — and much of the early scale change is water. Insulin resistance and carpal tunnel are dose-dependent and predictable.
💉 CJC-1295 W/ Dac
The DAC binds albumin and extends half-life to about a week, producing a sustained GH elevation rather than pulses. Sustained is not physiological, which is the trade — better IGF-1 area under the curve, more desensitisation risk.
💉 CJC-1295 No Dac
Same GHRH backbone without albumin binding, so you get a clean pulse that respects somatostatin feedback. The more physiological choice.
💉 Ipamorelin
Ghrelin-receptor agonist that triggers GH release with unusually little cortisol or prolactin. The selectivity is the entire reason it displaced GHRP-6 in practice.
💉 CJC No Dac/Ipamorelin
GHRH plus secretagogue hit two different receptors on the somatotroph simultaneously. The combined pulse is larger than the sum, which is real synergy and the standard stack for a reason.
💉 GHRP-2
A potent secretagogue with a moderate prolactin and cortisol rise attached. More GH than ipamorelin, less clean.
💉 GHRP-6
The strongest appetite stimulus of the secretagogues — useful in a bulk, disqualifying in a cut.
💉 Hexarelin
The most potent GH release of the group, with the fastest desensitisation. Short cycles only, and it has cardioprotective effects independent of GH that are interesting on their own.
💉 Sermorelin
GHRH 1-29, the shortest active fragment. Gentle, physiological, and the safest entry point into this pathway.
💉 MK-677
Oral, non-peptide, 24-hour GH and IGF-1 elevation. Lean mass rises consistently in trials — as does appetite, fasting glucose and fluid retention. A bulking tool that is honest about being one.
💉 IGF-LR3
Long-arg-3 IGF-1 resists binding proteins, so far more free IGF-1 reaches the receptor. Systemically active, which is both why it works and why the hypoglycaemia and unrestricted-growth concerns are legitimate.
💉 IGF-1 DES
A truncated IGF-1 with very short local action — the argument is site-specific hypertrophy at the trained muscle without systemic IGF-1 elevation.
💉 MGF
Mechano-growth factor, the splice variant expressed by muscle after mechanical damage. It activates satellite cells; the native peptide's half-life is measured in minutes, which is the practical problem.
💉 PEG-MGF
PEGylation extends MGF's half-life from minutes to hours, which is the only way the mechanism gets a chance to matter systemically.
The other 5 routes to build muscle & strength
Pick the pathway that matches where you are actually stuck. An appetite drug does nothing for someone who already undereats.
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Dosing schedules, stacking, cycle timing and Coach Cam's notes live inside the Academy — plus the full interactive Vault.
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Frequently asked questions
Growth hormone drives IGF-1, and IGF-1 activates PI3K/Akt/mTOR — the central hypertrophy signal. The honest read: GH is excellent for connective tissue, recovery and body composition, and a weaker direct hypertrophic agent than its reputation. Most of what people attribute to it is fluid and glycogen.
14 options are mapped to this pathway in the Vault, including HGH, CJC-1295 W/ Dac, CJC-1295 No Dac, Ipamorelin. They are grouped by the mechanism they act through rather than ranked by how much trial evidence exists — 3 carry clinical validation and 11 are mechanistic predictions.
IGF-1 is the only honest read on whether a GH protocol is doing anything — GH itself is pulsatile and a single draw is close to meaningless. Track fasting glucose and insulin alongside, because the most predictable cost of this pathway is insulin resistance and it arrives quietly. The markers worth checking are IGF-1 (Insulin-like Growth Factor 1), Growth Hormone, Serum, Fasting Insulin, HbA1c (Hemoglobin A1c).
Unproven is not the same as ineffective. Of the 14 options on this pathway, 3 have clinical validation and 11 are graded theoretical — meaning the mechanism is sound but the specific human trial has not been run, which is true of a great deal of what works in this space. Nothing on this page is ordered by evidence tier, because sorting by trial count would bury the compounds you came looking for.