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STACK CHAPTER

C
Animal replicated
Research chemicalPeptide
RouteInjectableGray-market only
Published literature
2human RCTs0human studies0animal0in vitro
Quick take
What it is
Peptide
Why people use it
Used primarily for tissue repair and healing and muscle and performance.
What the evidence supports
IGF-1 (insulin-like growth factor 1) is the primary downstream marker of GH axis activity. It is the only practical way to verify the GH Stack is producing meaningful GH elevation and to identify over-elevation risk.
If you only read one thing

The GH Stack has better mechanistic and clinical supporting evidence than any other stack in this book. The GHRH+GHRP synergy is replicated across species, multiple compound pairs, and over 30 years of research. CJC-1295 has Phase 1/2 human trial data (Teichman 2006: IGF-1 elevation +35-120% dose-dependent). Ipamorelin's selectivity advantage (no cortisol, no prolactin, no ACTH) was demonstrated in human pharmacology by Raun et al. (1998). The central tension is not evidence quality — it is the DAC distinction. A significant portion of community users receive or purchase CJC-1295 WITH DAC believing it is equivalent to CJC-1295 without DAC. It is not. DAC fundamentally changes the pharmacology from pulsatile to sustained — producing receptor desensitization and blunting natural GH pulsatility rather than enhancing it. Getting the DAC question right is the most important practical element of this chapter.

Properties
Not injectable
Evidence
CAnimal replicated
Stack Type
GH secretagogue combination. Not FDA-approved for these indications. Research protocol. Type: stack. Slug: gh-stack. stackGrade: B (GHRH+GHRP synergy is well-established in clinical research; specific CJC-1295 no-DAC + Ipamorelin combination has strong supporting evidence). Components: cjc-1295-no-dac, ipamorelin. Related stacks: metabolic-stack.
Stack Indication
Growth hormone optimization: improved sleep quality (SWS enhancement), body composition (fat loss, lean mass support), recovery acceleration, anti-aging GH axis support. Not a substitute for diagnosed GH deficiency treatment with pharmaceutical HGH.
The Two Mechanisms
CJC-1295 (no DAC) = Modified GRF 1-29; GHRH analog; activates GHRH receptor on pituitary somatotrophs; amplifies GH pulse amplitude; half-life ~30 min (injectable pulse). Ipamorelin = selective ghrelin receptor agonist (GHS-R1a); triggers clean GH pulse without raising cortisol, prolactin, or ACTH; half-life ~2 hours. Together: GHRH receptor activation + ghrelin receptor activation = synergistic GH pulse 3-5x larger than either alone.
The DAC Distinction
CJC-1295 WITH DAC (Drug Affinity Complex): half-life ~8 days; once-weekly dosing; produces sustained, non-pulsatile GH elevation; blunts natural GH pulsatility; may cause receptor desensitization. CJC-1295 WITHOUT DAC (Mod GRF 1-29): half-life ~30 minutes; clears between doses; preserves pulsatile GH release pattern; physiologically appropriate. For most community protocols: no DAC is preferred. DAC is never appropriate for the bedtime pulsatile protocol.
The Empty Stomach Rule
Food — especially carbohydrates — raises blood glucose and insulin, which directly suppresses GH release from the pituitary. Insulin and GH are counter-regulatory hormones. Injecting this stack within 1-2 hours of a carbohydrate-containing meal substantially blunts or eliminates the GH pulse. Wait 2+ hours after any significant meal. Do not eat for 20-30 minutes after injection. This rule is not optional and not community superstition — it has a clear physiological mechanism.
Molecular profile
MW ·
Half-life ·
Class · Peptide
Route ·
~14 min

The GH Stack exists because the pituitary has two different receptor systems for GH release, and activating both simultaneously produces a response that is not achievable by activating either alone.

Growth hormone release from pituitary somatotrophs is regulated by two primary hypothalamic inputs operating in parallel: GHRH (growth hormone-releasing hormone), which increases GH synthesis and amplifies pulse amplitude via the GHRH receptor; and ghrelin (produced by the stomach and hypothalamus), which triggers GH release via the ghrelin receptor (GHS-R1a) and simultaneously inhibits somatostatin — the GH-suppressing hormone. These are completely independent receptor systems. A signal at the GHRH receptor does not saturate the ghrelin receptor, and vice versa. When both signals arrive at the somatotroph simultaneously, the resulting GH pulse is substantially larger than either signal could produce alone — not additive, but synergistic.

This synergy was established in clinical research before either CJC-1295 or ipamorelin existed. Bowers et al. (1991) demonstrated that combined GHRH + GHRP-6 administration produced GH peaks 2-3x higher than either alone. The mechanism is the same for any GHRH analog + any GHRP: the two receptor systems amplify each other. CJC-1295 (no DAC) is the GHRH analog in the GH Stack; ipamorelin is the GHRP. Their specific combination is supported by the broader GHRH/GHRP synergy literature and by ipamorelin's selectivity profile that makes it cleaner than older GHRPs.

THE CENTRAL TENSION

The GH Stack has better mechanistic and clinical supporting evidence than any other stack in this book. The GHRH+GHRP synergy is replicated across species, multiple compound pairs, and over 30 years of research. CJC-1295 has Phase 1/2 human trial data (Teichman 2006: IGF-1 elevation +35-120% dose-dependent). Ipamorelin's selectivity advantage (no cortisol, no prolactin, no ACTH) was demonstrated in human pharmacology by Raun et al. (1998). The central tension is not evidence quality — it is the DAC distinction. A significant portion of community users receive or purchase CJC-1295 WITH DAC believing it is equivalent to CJC-1295 without DAC. It is not. DAC fundamentally changes the pharmacology from pulsatile to sustained — producing receptor desensitization and blunting natural GH pulsatility rather than enhancing it. Getting the DAC question right is the most important practical element of this chapter.

Protocol Element

Standard (1x daily)

Advanced (2-3x daily)

CJC-1295 (no DAC) per injection

100-200 mcg

100-200 mcg per injection

Ipamorelin per injection

200-300 mcg

200-300 mcg per injection

Injection frequency

Once daily (before bed)

2-3x daily (before bed + morning; optionally pre-workout)

Fasting requirement

2+ hours post-meal; 20-30 min pre-meal after injection

Same per injection

Blended vial option

5mg/5mg (CJC-1295 no-DAC + ipamorelin) common; verify no-DAC

Same blended vial; multiple injections from same vial

Cycle length

8-12 weeks standard; some extend to 6 months with monitoring

8-12 weeks; shorter rest periods used by some advanced users

Rest period

4-8 weeks (to allow pituitary receptor recovery)

Community variable; 4 weeks minimum

Monitoring

IGF-1 at baseline + 6-8 weeks; fasting glucose + HbA1c

Same + more frequent IGF-1 (every 6 weeks on multi-dose)

CJC-1295 without DAC (also called Modified GRF 1-29, Mod GRF 1-29, or Sermorelin analog) is a synthetic 29-amino acid GHRH analog derived from the first 29 amino acids of native GHRH. It was developed by ConjuChem and underwent Phase 1/2 clinical trials. Without the DAC (Drug Affinity Complex) modification, it has a plasma half-life of approximately 30 minutes — comparable to natural GHRH. Each injection produces a GH pulse that rises and falls over 2-3 hours, preserving the pulsatile GH release pattern. This pulsatility is physiologically important: the body's GH axis operates in pulses, and sustained non-pulsatile GH elevation is less physiologically appropriate and can cause receptor downregulation.

CJC-1295 with DAC is chemically modified with a Drug Affinity Complex that allows it to covalently bind to albumin in the bloodstream, extending its half-life to approximately 8 days. A single injection maintains elevated GH stimulation for a week. This completely changes the pharmacological profile: instead of discrete pulses (physiological), it produces sustained tonic GHRH receptor stimulation (non-physiological). Over time, this sustained stimulation can cause GHRH receptor downregulation and blunt natural GH pulsatility. The once-weekly dosing convenience comes at the cost of physiological appropriateness. For the bedtime pulsatile protocol described in this chapter, DAC is fundamentally incompatible — the point is to create a controlled pulse at a specific time, which sustained DAC cannot produce.

Feature

CJC-1295 WITHOUT DAC (Mod GRF 1-29)

CJC-1295 WITH DAC

Half-life

~30 minutes

~8 days

GH release pattern

Pulsatile — peaks and clears within 2-3 hours

Sustained — continuous GHRH stimulation for ~1 week

Dosing frequency

With each injection (1-3x daily for GH Stack)

Once weekly

Pulsatility preservation

Yes — physiologically appropriate

No — blunts natural pulsatility

Receptor desensitization risk

Low with appropriate cycling

Higher with continuous sustained stimulation

For the GH Stack bedtime protocol

YES — the correct compound

NO — incompatible with pulsatile protocol

Community name confusion

Often called simply 'CJC-1295' — always verify no-DAC

Often sold as 'CJC-1295 DAC' or 'CJC-1295 with DAC'

Ipamorelin is a synthetic pentapeptide (5 amino acids) that agonizes the ghrelin receptor (GHS-R1a) on pituitary somatotrophs. It was developed by Novo Nordisk and characterized in human pharmacology by Raun et al. (1998). Its defining characteristic: selectivity. Unlike older GHRPs (GHRP-2, GHRP-6, hexarelin), ipamorelin produces GH release without meaningful elevation of cortisol, prolactin, or ACTH. This is not a minor distinction — cortisol elevation from GHRP-2 or GHRP-6 partially counteracts the anabolic and recovery benefits of GH release. Ipamorelin's clean pharmacological profile makes it the preferred GHRP for community use and the compound in the GH Stack.

GHRP

GH Release

Cortisol

Prolactin

ACTH

Preference

Ipamorelin

Strong (via GHS-R1a)

No significant elevation

No significant elevation

No significant elevation

Preferred — cleanest profile

GHRP-6

Strong

Elevated

Elevated

Elevated

Less preferred — side effects

GHRP-2

Very strong

Elevated

Elevated

Elevated

Less preferred — more sides

Hexarelin

Very strong

Elevated

Elevated

Elevated

Rarely used — cardiac receptor concern

CJC-1295 (no DAC) activates the GHRH receptor (GHRHR) on pituitary somatotrophs, increasing cAMP, promoting GH gene transcription, and amplifying the amplitude of the GH pulse. Ipamorelin activates GHS-R1a (ghrelin receptor) on the same somatotrophs, triggering calcium-mediated GH exocytosis and simultaneously inhibiting somatostatin release from the hypothalamus. Somatostatin is the brake on GH release — its inhibition removes a suppressive input that would otherwise limit the magnitude of the pulse. When CJC-1295 (amplitude amplifier) and ipamorelin (pulse trigger + somatostatin brake remover) arrive at the same time, the somatotroph receives two simultaneous pro-GH signals with one simultaneous brake-release signal. The result: a GH pulse 3-5x larger than either compound alone in clinical research models, approaching or exceeding the amplitude of the largest natural physiological GH pulses.

The research supporting this synergy: Bowers et al. (1991, Journal of Clinical Endocrinology & Metabolism) — combined GHRH + GHRP-6 administration; GH peaks 2-3x higher than either alone. The mechanism is identical for any GHRH analog + any GHS-R1a agonist, including the CJC-1295 + ipamorelin pair. Teichman et al. (2006, Journal of Clinical Endocrinology & Metabolism) — CJC-1295 alone in humans; IGF-1 elevation +35-120% dose-dependent; sustained GH elevation with the DAC version. Raun et al. (1998) — ipamorelin human pharmacology; selective GH release without cortisol or prolactin. stackGrade B is assigned because the mechanism and synergy are validated in human clinical research, even though the specific CJC-1295 no-DAC + ipamorelin combination at community doses has not been formally evaluated in a dedicated controlled trial.

The most important practical element of the GH Stack is timing. When you inject determines how large the resulting GH pulse is, and whether you capture the sleep-related GH amplification that makes this protocol distinctively effective.

EMPTY STOMACH — PHARMACOLOGICAL REQUIREMENT, NOT CONVENTION

Carbohydrate and fat intake raises blood glucose and insulin. Insulin is counter-regulatory to GH — elevated insulin suppresses GH release from the pituitary via direct somatotroph inhibition and indirect somatostatin elevation. Injecting the GH Stack within 1-2 hours of a significant meal — particularly a carbohydrate-heavy meal — substantially blunts the GH pulse. In practice: wait at least 2 hours after any significant meal before injecting; do not eat for 20-30 minutes after injection. The before-bed injection naturally satisfies this: dinner 3+ hours before bed, no food after injection. This is one of the most frequently violated rules in community GH Stack use and the most common reason for a disappointing response.

The primary injection in the GH Stack protocol is before bed. The justification is not merely convenience — it is pharmacological. The largest natural GH pulse in healthy adults occurs during slow-wave sleep (SWS), typically within the first 1-2 hours of sleep onset. GHRH itself enhances slow-wave sleep duration and intensity — Steiger et al. (1992) demonstrated this in both young and elderly subjects in controlled sleep studies. Injecting CJC-1295 + ipamorelin before bed therefore does two things simultaneously: it triggers a synergistic GH pulse and it amplifies the slow-wave sleep during which that pulse is occurring. The GH pulse and the sleep enhancement reinforce each other. This is the primary reason the bedtime injection is not interchangeable with any other time of day for GH-related goals.

The standard single-injection protocol uses before-bed only. Some community users and clinics use 2-3 injections daily: morning (fasted, before breakfast) and/or pre-workout (60-90 minutes before training, on empty stomach). The rationale: more injections = more daily GH pulse amplitude, supporting body composition and recovery goals. The practical constraint: multiple daily injections require fasted states at multiple time points — which conflicts with normal eating patterns for most people. The before-bed single injection is the most adherence-compatible protocol and captures the most pharmacologically important timing window.

Injection Time

Fasting Requirement

Rationale

Best For

Before bed (primary)

Last meal 2-3+ hours before; no food after injection

Amplifies natural sleep-phase GH pulse; GHRH enhances SWS; easiest fasting window

All users; best sleep quality and recovery benefit

Morning (fasted)

Upon waking; before breakfast

Fasted AM GH pulse; avoids postprandial insulin suppression

Users targeting body composition; second injection in 2x daily protocol

Pre-workout (60-90 min pre)

2+ hours after last meal

GH pulse during workout amplifies lipolysis and anabolic signaling

Advanced users; 3x daily protocol; requires dedicated fasting window before training

IGF-1 (insulin-like growth factor 1) is the primary downstream marker of GH axis activity. It is the only practical way to verify the GH Stack is producing meaningful GH elevation and to identify over-elevation risk.

GH stimulates the liver to produce IGF-1, which circulates with a half-life of approximately 15-20 hours — unlike GH itself, which pulses (half-life ~20 minutes) and is difficult to capture with standard serum tests. Measuring GH directly requires timed samples during a pulse. Measuring IGF-1 measures the cumulative GH signal over the preceding days. For GH Stack monitoring: baseline IGF-1 (before starting); recheck at 6-8 weeks. Target range: the upper half of the age-appropriate reference range, approximately 200-350 ng/mL for adults (age and sex-specific; always interpret against the laboratory's reference range for the patient's age). Important: IGF-1 must be interpreted as SDS (standard deviation score) or against age-specific norms — not in absolute terms. An IGF-1 of 300 ng/mL may be within range for a 30-year-old and above range for a 60-year-old. Elevated IGF-1 above the upper limit of the age-appropriate range over time raises the theoretical risk of insulin resistance and IGF-1-mediated growth promotion (including in subclinical or undiagnosed cancers). If IGF-1 exceeds the upper reference range, reduce dose or injection frequency.

Fasting glucose and HbA1c are secondary monitoring parameters: GH has insulin-antagonizing effects, and long-term GH axis stimulation can increase fasting glucose in susceptible individuals. Baseline and annual fasting glucose is recommended for any extended GH Stack protocol.

ACTIVE MALIGNANCY — CAUTION

IGF-1 is a growth factor with mitogenic activity. Elevated IGF-1 is associated in epidemiological studies with increased risk of certain cancers. For individuals with active malignancy, the GH Stack is contraindicated. For individuals with personal or strong family history of cancer, physician consultation before starting is essential. This caution applies to all compounds that elevate IGF-1, including MK-677, tesamorelin, and the GH Stack.

  • Using CJC-1295 WITH DAC for the pulsatile protocol: produces sustained non-pulsatile GH stimulation; blunts natural pulsatility; wrong compound for this protocol. Always verify 'no DAC' or 'Mod GRF 1-29.'
  • Injecting within 1-2 hours of a carbohydrate meal: insulin suppresses GH release; the pulse is substantially blunted or eliminated. The fasting window is not optional.
  • Not cycling: running the GH Stack indefinitely without rest periods risks pituitary desensitization. 8-12 weeks on, 4-8 weeks off is the standard cycle structure.
  • Ignoring IGF-1 monitoring: without IGF-1 measurement, there is no feedback on whether the protocol is working or over-working the GH axis. Baseline + 6-8 week check is the minimum.
  • Expecting fat loss without dietary discipline: GH supports lipolysis but does not override caloric surplus. Body composition changes from the GH Stack are real but require appropriate dietary context.

Bowers CY, Sartor AO, Reynolds GA, Badger TM. (1991). On the actions of the growth hormone-releasing hexapeptide, GHRP. Endocrinology. 128(4):2027-35. [Foundational GHRH+GHRP synergy; combined administration produces GH peaks 2-3x higher than either alone; mechanism identical for any GHRH analog + GHRP pair.]

Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. (2006). Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. Journal of Clinical Endocrinology & Metabolism. 91(3):799-805. [Phase 1/2 human data; CJC-1295 DAC; IGF-1 elevation +35-120% dose-dependent; human pharmacology established.]

Raun K, Hansen BS, Johansen NL, et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 139(5):552-61. [Ipamorelin human pharmacology; selective GH release without cortisol, prolactin, or ACTH; the selectivity paper that established ipamorelin's profile.]

Steiger A, Guldner J, Hemmeter U, Rothe B, Wiedemann K, Holsboer F. (1992). Effects of growth hormone-releasing hormone and somatostatin on sleep EEG and nocturnal hormone secretion in male controls. Neuroendocrinology. 56(4):566-73. [GHRH enhances slow-wave sleep; pharmacological justification for the bedtime injection.]

The GH Stack is the best-evidenced peptide combination in this book. The synergy is mechanistically well-established, replicated across research contexts, and supported by human clinical data on both components. Getting the DAC question right and respecting the fasting window are the two practical elements that determine whether the protocol works.

  • Standard protocol: CJC-1295 no-DAC 100-200 mcg + Ipamorelin 200-300 mcg; once daily before bed; fasted 2+ hours.
  • DAC vs no DAC: verify no-DAC. CJC-1295 with DAC is the wrong compound for a pulsatile bedtime protocol.
  • Fasting window: non-negotiable. 2+ hours after last meal; 20-30 min before eating after injection.
  • Cycle: 8-12 weeks; 4-8 weeks off; IGF-1 at baseline and 6-8 weeks.
  • stackGrade: B — GHRH+GHRP synergy is clinically validated; specific compound pair supported by individual human pharmacology studies.

STACK SUMMARY

GH Stack: type=stack; slug=gh-stack; stackGrade=B. COMPONENTS: cjc-1295-no-dac + ipamorelin. relatedStacks: metabolic-stack. indication: GH axis optimization; sleep quality, body composition, recovery, anti-aging. studyCounts: humanRct: 2 (individual components), combinationRct: 0, animal: 20+. THE DAC DISTINCTION: CJC-1295 NO DAC (Mod GRF 1-29) = half-life ~30 min; pulsatile; correct for this protocol. CJC-1295 WITH DAC = half-life ~8 days; sustained; non-pulsatile; WRONG for this protocol; risks receptor desensitization. MECHANISM: CJC-1295 no-DAC → GHRH receptor on somatotrophs → GH synthesis + pulse amplitude ↑. Ipamorelin → GHS-R1a (ghrelin receptor) → GH exocytosis + somatostatin inhibition. Together: 3-5x synergistic GH pulse (Bowers et al 1991). IPAMORELIN SELECTIVITY: GH release without cortisol/prolactin/ACTH ↑ (Raun 1998). GHRP comparison: ipamorelin preferred over GHRP-2, GHRP-6, hexarelin for cleaner profile. SLEEP: GHRH enhances SWS (Steiger 1992); bedtime injection amplifies largest natural GH pulse during deep sleep. FASTING: MANDATORY. Carbs → insulin → GH suppression. 2+ hours post-meal; no food 20-30 min post-injection. DOSE: CJC-1295 no-DAC 100-200 mcg + Ipamorelin 200-300 mcg per injection. FREQUENCY: 1x (before bed, minimum); up to 3x daily (bed + AM + pre-workout). BLENDED VIALS: 5mg/5mg common; verify no-DAC. CYCLE: 8-12 weeks on; 4-8 weeks off. MONITORING: IGF-1 at baseline + 6-8 weeks; fasting glucose + HbA1c annually on extended protocols; target IGF-1 upper half of age-appropriate range. ACTIVE MALIGNANCY: caution (IGF-1 is mitogenic). COMMON MISTAKES: using DAC version; injecting with food; not cycling; no IGF-1 monitoring.

— End of GH Stack —

THE PEPTIDE BIBLE | GH Stack | For Research & Educational Purposes Only