TL;DR
- 1.Ipamorelin and CJC-1295 together produce a GH pulse 2 to 3 times larger than either peptide alone -- not because the doses add up, but because they fire two separate triggers at the same moment and the signal multiplies.
- 2.Most protocols get one thing critically wrong: CJC-1295 with DAC eliminates the pulsatile GH effect entirely. For the standard ipamorelin stack, you want CJC-1295 without DAC (modified GRF 1-29), which has a 30-minute action window that matches ipamorelin's timing.
- 3.The right starting dose is 100 mcg of each, not body weight. Check your IGF-1 at week 4. If you are in range, maintain the dose. If you are above range, drop to 75 mcg. If you are below, increase to 150 mcg.
- 4.About 1 in 3 people carry a growth hormone receptor variant (the d3-GHR deletion) that makes them respond 1.7 to 2 times more strongly than average. These users should start at 100 mcg, not 200 mcg, and test bloodwork at week 4 rather than week 8.
- 5.As of mid-2026, neither peptide has an active FDA compounding pathway. They are not DEA-scheduled controlled substances, but licensed US pharmacies are operating in a gray zone. The next regulatory review is expected in early 2027.
The combination of ipamorelin and CJC-1295 produces a GH pulse 2 to 3 times larger than either peptide produces on its own. Not because you are taking twice as much. Because they activate two completely separate pathways at the same time and the brain's GH release mechanism responds to both signals simultaneously.
A 2001 study in the Journal of Clinical Endocrinology and Metabolism by Hataya et al. confirmed this synergy in human subjects: co-administration of a GHRH analog and a GHRP produced GH peaks far beyond what additive math would predict. The ipamorelin and CJC-1295 combination uses the same dual-trigger mechanism. That is why this stack dominates longevity and performance peptide protocols despite there being no published head-to-head RCT testing the specific combination.
But two things destroy the stack's effectiveness in practice, and almost no guide covers either of them: the version of CJC-1295 you choose, and what your bloodwork tells you before you raise the dose.
2-3x The GH pulse when a GHRH peptide and a GHRP are co-administered, compared to either agent given alone. Hataya et al., Journal of Clinical Endocrinology and Metabolism, 2001. The effect is not additive. It is synergistic because GHRH and ghrelin receptors operate independent pathways that converge at the pituitary somatotroph.
Why ipamorelin and CJC-1295 work differently than other GH stacks
Ipamorelin is a selective growth hormone releasing peptide (GHRP). It mimics ghrelin at the GHSR receptor on pituitary somatotrophs, triggering a GH pulse. What sets it apart from older GHRPs like GHRP-2 or hexarelin is that selectivity: ipamorelin produces no meaningful elevation of cortisol, prolactin, or ACTH at any therapeutic dose, which Raun et al. confirmed in a 1998 study published in the European Journal of Endocrinology. Its terminal half-life is approximately two hours. GH peaks around 40 minutes post-injection and returns to baseline by three to six hours. A clean, short, selective pulse.
CJC-1295 (without DAC, also marketed as modified GRF 1-29) is a GHRH analog. It activates the GHRH receptor on the same somatotrophs through a completely separate receptor from ipamorelin. Its half-life is approximately 30 minutes without the DAC moiety, giving it an action window that maps closely onto ipamorelin's. Both peptides peak, synergize, and clear within the same two to three hour window.
The synergy comes from the biology. GHRH receptor activation primes the somatotroph to release more GH per signal. GHSR activation provides the trigger. Firing both at the same time means more primed cells responding to a stronger trigger simultaneously. That is why the Hataya study found a result that was multiplicative, not additive.
Plain English: Think of your pituitary like a concert speaker system. CJC-1295 turns up the amplifier (GHRH primes the cells). Ipamorelin hits the play button (GHSR triggers release). Neither alone gives you full volume. Both together at the same moment give you the show.
CJC-1295 with DAC breaks the stack. Here is why.
This is the piece most stacking guides get completely wrong. There are two compounds sold as "CJC-1295." They behave oppositely in this protocol.
CJC-1295 with DAC (Drug Affinity Complex) has a half-life of 5.8 to 8.1 days. Teichman et al. demonstrated in a 2006 double-blind RCT in JCEM that a single dose sustained GH elevation for six days and pushed IGF-1 1.5 to 3 times above baseline for nine to eleven days with weekly dosing. That sounds good. But it means your GH is continuously elevated for most of the week, not pulsed.
Continuous GH elevation is not what the stack is designed to do. The pituitary uses pulsatile GH release for a reason: receptors need time between pulses to resensitize. Running a week-long GH elevation via CJC-1295 with DAC while injecting ipamorelin three times daily does not give you three amplified pulses. It gives you blunted pulsatile response on top of a flat sustained baseline. The receptor kinetics are working against you.
Half-life: ~30 minutes. Action window matches ipamorelin. Co-inject both at the same time. You get a sharp, synergistic pulse. Receptor resensitizes between doses. This is what the standard stack protocol uses.
Half-life: 5.8 to 8.1 days. Sustained GH elevation for most of the week. Works as a standalone weekly inject for IGF-1 elevation. Does not pair well with ipamorelin for pulsatile GH goals. Receptor context is different.
The practical check: if your peptide is labeled "CJC-1295 2mg" or "CJC-1295 5mg" without specifying DAC or "mod GRF 1-29", contact the supplier before using it in this stack. The two compounds look identical in powder form and are frequently mislabeled.
When is the best time to take CJC-1295 and ipamorelin?
Evening dosing, fasted, 60 to 90 minutes after your last meal. This timing captures the brain's natural GH release window. Endogenous GH pulses peak during slow-wave sleep. Dosing before bed extends and amplifies that peak rather than competing with the daytime somatostatin suppression that blunts daytime injections.
If you use the stack twice daily (some protocols do for accelerated tissue repair), the standard split is evening plus morning fasted. The morning dose catches a secondary natural GH window but produces a smaller absolute pulse because somatostatin levels are higher during daytime hours. Evening remains the priority dose for most users. For a detailed breakdown of how somatostatin timing affects your result, see How GH Pulses Actually Work: Why Dosing Ipamorelin at the Wrong Time Wastes Half the Effect.
How to inject: the co-inject protocol
Draw both peptides into the same syringe. Inject subcutaneously, typically abdomen, 60 to 90 minutes post-meal. The co-inject ensures simultaneous receptor activation, which is what produces the synergistic pulse. Splitting them 20 to 30 minutes apart reduces synergy.
Pinch the skin, 45-degree angle, release the pinch before withdrawing. Rotate sites. If you are running twice daily, alternate abdomen and thigh to give each site time to recover.
The dosage table most guides skip: starting by bloodwork response
Most protocols give you a flat number: "100 to 300 mcg of each." That range is not arbitrary, but it tells you nothing about where to start or when to adjust. The right protocol is driven by your IGF-1 lab result, not your body weight and not the upper bound on someone else's protocol.
Standard reference ranges for IGF-1 vary by age. The goal on a growth peptide stack is not to maximize IGF-1 as high as possible. It is to keep IGF-1 in the upper quartile of the age-appropriate range. Above range, you raise the risk of fluid retention, joint stiffness, carpal tunnel symptoms, and elevated fasting glucose. For the full symptom checklist and what to do about each, see 9 Signs Your IGF-1 Is Too High.
| Your baseline IGF-1 | Starting dose (each peptide) | First bloodwork check | Target after adjustment |
|---|---|---|---|
| Below age-range midpoint | 100 mcg once daily, evening | Week 4 | Upper quartile of age range |
| At age-range midpoint | 100 mcg once daily, evening | Week 6 | Upper quartile of age range |
| Already in upper quartile | 75 mcg once daily, evening | Week 4 | Maintain, do not push higher |
| No baseline reading | 100 mcg once daily, evening | Week 4 (mandatory) | Establish baseline before increasing |
If your week-4 IGF-1 is below the upper quartile, increase each peptide by 50 mcg increments. Retest at four weeks. The ceiling for most clinical protocols is 300 mcg of each. Above that dose, the incremental IGF-1 benefit flattens while the adverse effect profile steepens. For how to interpret the ratio of IGF-1 to IGFBP-3 (which matters more than absolute IGF-1 alone), see What Your IGF-1 to IGFBP-3 Ratio Actually Tells You.
"A single subcutaneous injection of CJC-1295 resulted in mean GH increases of 2- to 10-fold for 6 days or more and mean IGF-1 increases of 1.5- to 3-fold for 9 to 11 days after multiple doses. No serious adverse events were reported."
Teichman et al., Journal of Clinical Endocrinology and Metabolism, 2006
How your genetics change the right starting dose
About 30 to 40 percent of people carry a deletion in exon 3 of the growth hormone receptor gene. This d3-GHR variant produces a receptor with approximately 30 percent greater signaling efficiency per GH molecule compared to the full-length receptor (Dos Santos et al., 2004). In practice, this means d3-GHR carriers achieve the same downstream IGF-1 response from a lower dose of GH stimulation.
Ben-Avraham et al. confirmed in a 2017 Science Advances study that d3/d3 homozygotes show exceptional GH sensitivity and longevity associations. Heterozygous d3/fl carriers represent the largest subgroup. Both d3 groups respond more robustly than full-length homozygotes to the same ipamorelin and CJC-1295 dose.
The second key variant is in the IGFBP3 gene. Gao et al. found in a 2018 Frontiers in Endocrinology study that C-allele carriers at rs2854744 showed post-treatment IGF-1 levels averaging 855.5 ng/mL versus 519.2 ng/mL in A/A carriers on the same GH-stimulating protocol. The mechanism is lower circulating IGFBP3, which leaves more IGF-1 bioavailable. If you carry this variant, your IGF-1 readout on bloodwork will naturally run higher, so the upper-quartile target applies but you will reach it more quickly.
| Genotype | Expected response | Starting dose | First bloodwork |
|---|---|---|---|
| d3/d3 (GHR exon 3 deletion, both copies) | Highest sensitivity (1.7-2x stronger) | 75 mcg each | Week 4 |
| d3/fl (one deletion copy) | Moderately elevated sensitivity | 100 mcg each | Week 4 |
| fl/fl (standard full-length) | Average responder | 100-150 mcg each | Week 6 |
| IGFBP3 C/C or C/A at rs2854744 | Higher circulating IGF-1 for same dose | 100 mcg each | Week 4 |
| GHSR partial loss-of-function | Blunted ipamorelin response | 150 mcg ipamorelin, 100 mcg CJC | Week 4 |
You can check your d3-GHR status in 23andMe or AncestryDNA raw data. The relevant locus is the GHR gene region on chromosome 5. If you have not tested your DNA yet, running the standard 100 mcg starting dose with week-4 bloodwork gives you the same information empirically. Your IGF-1 response at four weeks reveals your functional sensitivity class without the genetic test. Find your matched protocol at the ipamorelin peptide page.
1 in 3 people carry at least one copy of the d3-GHR deletion, putting them in the higher-sensitivity class for GH secretagogue response. These individuals respond to ipamorelin and CJC-1295 as if the dose were 1.7 to 2 times higher than it appears on the label. Standard bloodwork at week 8 comes too late to catch a brewing IGF-1 overshoot.
What to do if you are a non-responder
Flat IGF-1 at week 4 despite consistent dosing and correct timing (evening, fasted, co-inject) points to one of three problems: poor peptide quality, a GHSR partial loss-of-function variant, or inadequate pituitary reserve from age-related decline.
Quality is the first variable to rule out. Ipamorelin is susceptible to oxidation and degrades quickly at room temperature. If your peptide has been improperly stored or is from an unverified source, the active compound concentration may be far below label. Reconsider your source before increasing dose.
If quality is confirmed, GHSR partial loss-of-function is worth considering. This variant blunts the ipamorelin side of the stack. CJC-1295 alone (as the GHRH driver) often preserves significant IGF-1 response in these users, and pairing it with sermorelin (a different GHRH analog with a documented compounding pathway) can substitute for the ipamorelin component. For the complete non-responder analysis, see GHSR Loss-of-Function: Why Some People Cannot Respond to Ipamorelin at Any Dose.
How long to run the stack before taking a break
The most common cycle structure is 12 weeks on, four weeks off. The off period allows GHSR receptor resensitization and a return to baseline IGF-1. Running the stack indefinitely without breaks does not produce additional benefit and increases the chance of GHSR desensitization. Hexarelin demonstrated complete GHSR desensitization within two weeks of daily use. Ipamorelin desensitizes more slowly, but the receptor reset argument for cycling holds.
Bloodwork before your next cycle is not optional. Your pre-cycle IGF-1 reading tells you whether the receptor reset has completed. If IGF-1 is still above the upper quartile of your age range at the start of week 13, extend the off period by two weeks. If it has normalized, you can restart at the same dose. For how long receptor resensitization takes after different GH peptides, see How Long Does It Actually Take for GH Receptors to Reset After a Peptide Cycle.
Common stacking additions
Ipamorelin and CJC-1295 pair well with GHK-Cu for connective tissue and skin repair, with BPC-157 for injury recovery (different mechanism, no receptor competition), and increasingly with GLP-1 agonists for users on semaglutide or tirzepatide who want to preserve lean mass during weight loss. That last combination is growing in clinical longevity practice but has no published human protocol data yet.
What to avoid stacking: other GHRPs (GHRP-2, hexarelin) added to ipamorelin do not increase the GH pulse and increase the side-effect profile. The benefit of ipamorelin's selectivity comes from using it alone as the GHRP driver in the combination.
Is the ipamorelin CJC-1295 stack legal in the US right now?
Neither peptide is FDA-approved. Neither is DEA-scheduled. Possession is not a federal criminal matter.
The compounding pathway is the complicated part. The FDA placed both peptides on the Category 2 interim 503A bulks list in October 2023, blocking licensed pharmacies from compounding them. In September 2024, both were removed from Category 2 after the original nominators withdrew, creating a gray zone rather than a green light. The FDA Pharmacy Compounding Advisory Committee (PCAC) voted in late 2024 against adding either peptide to the approved 503A bulks list, citing a cardiovascular adverse event profile for CJC-1295 and safety signals from an IV ipamorelin gut motility trial.
As of July 2026, neither peptide appears on the agenda for the upcoming July 23-24, 2026 PCAC meeting (which focuses on BPC-157, TB-500, Semax, and several others). The next anticipated review where ipamorelin and CJC-1295 could receive approved status is expected in early 2027 but is not confirmed. For context on which peptides are currently navigating the 503A process and what that means for access, see Are Peptides Legal in the US? A 2026 State-by-State Guide.
The practical implication: licensed US compounding pharmacies that dispense these peptides under prescription are operating without formal 503A authorization. Unregulated research chemical sources carry no quality guarantees. If you are prescribed this stack by a licensed clinician, your pharmacy is making a judgment call in an unresolved regulatory environment.
Verdict: the stack works, but the protocol details matter
Ipamorelin and CJC-1295 without DAC is the most mechanistically coherent GH secretagogue combination in practice, backed by solid individual-peptide data and a well-established synergy mechanism. The gaps in the standard protocol -- the wrong version of CJC-1295, dosing without bloodwork, ignoring genetic response predictors -- are why many users underperform or overshoot. Start at 100 mcg of each, check IGF-1 at week 4, and adjust based on where your labs land. If you know your GHR genotype, use it to set the starting dose.
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Frequently asked questions
When is the best time to take CJC-1295 and ipamorelin?
Evening, fasted, 60 to 90 minutes after your last meal. This timing captures the brain's natural GH release window during slow-wave sleep, amplifying the endogenous pulse rather than competing with the daytime somatostatin suppression that limits morning dosing. If you run twice daily, add a fasted morning dose as a second injection, but treat evening as the primary.
CJC-1295 with DAC or without DAC: which should I use with ipamorelin?
Without DAC (also called modified GRF 1-29) for the standard stack. CJC-1295 with DAC has a 5-to-8-day half-life that produces sustained GH elevation for most of the week, which eliminates the pulsatile synergy that makes the combination effective. Modified GRF 1-29 has a 30-minute half-life that matches ipamorelin's action window, so both peptides peak and clear together.
How long does the ipamorelin CJC-1295 stack take to work?
Most users notice improved sleep quality and recovery within two to three weeks. Measurable IGF-1 elevation shows on bloodwork at week four. Body composition changes (reduced fat, preserved muscle) typically require eight to twelve weeks to become visible. The peptides are working from day one, but the downstream effects accumulate over the full cycle.
What IGF-1 level should I aim for on this stack?
Upper quartile of the age-appropriate reference range for your lab's assay. Do not chase the absolute highest reading you can achieve. IGF-1 above the age-appropriate range raises risk of fluid retention, joint pain, carpal tunnel symptoms, and insulin resistance. The goal is optimization within normal, not supraphysiological elevation.
Can I take ipamorelin and CJC-1295 in the morning instead of at night?
Yes, but expect a smaller GH pulse. Morning somatostatin levels are elevated compared to the pre-sleep window, which blunts the pituitary response to both peptides. Morning dosing still works and is appropriate for users who need to dose around a sleep schedule. If you can only dose once daily, evening produces a larger result.
How long should I run the ipamorelin CJC-1295 stack before taking a break?
The standard cycle is 12 weeks on, four weeks off. The off period allows GHSR receptor resensitization. Check IGF-1 before restarting. If it has not normalized to baseline after four weeks, extend the break by two weeks before the next cycle. Running the stack without cycle breaks does not improve outcomes and increases the risk of receptor desensitization over time.
What are the main side effects of the ipamorelin CJC-1295 stack?
At appropriate doses, the most common effects are water retention (mild, usually resolves within the first two weeks), increased hunger shortly after injection (GH secretagogue effect), and fatigue if IGF-1 runs too high. Ipamorelin's selectivity means it does not raise cortisol or prolactin, unlike older GHRPs. Any joint pain, carpal tunnel symptoms, or meaningful blood glucose changes signal that your IGF-1 may be above range and warrant bloodwork.
This article is for informational and educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional before starting any peptide protocol. Individual results vary.