Lean mass stack: IGF-1 LR3 + CJC-1295 / Ipamorelin
Directly stimulate IGF-1 signalling for hypertrophy in trained lifters.
This is the advanced end of the range and the one with the least margin for error. IGF-1 LR3 is dosed at 20–50 mcg daily, subcutaneously, usually pre- or post-workout, on top of a pre-bed CJC-1295 100 mcg plus ipamorelin 100 mcg pairing. Where the GH pulse stack asks the pituitary to release more hormone, IGF-1 LR3 bypasses it and signals directly. Cycling is strict — four weeks on, four weeks off — because chronic exposure downregulates the receptors the whole protocol depends on.
Educational only
This page summarizes published research and community protocols. It is not medical advice, and nothing here is a recommendation to use these compounds. Get baseline bloodwork and work with a licensed clinician first. See our medical disclaimer.
The protocol
| Compound | Typical dose | Frequency | Role |
|---|---|---|---|
| IGF-1 LR3 | 20–50 mcg | Daily, subcutaneous, pre- or post-workout | Long-acting IGF-1 analog; signals hypertrophy pathways directly rather than via GH. |
| CJC-1295 (no DAC) | 100 mcg | Pre-bed, subcutaneous | Maintains the natural GH pulse alongside the exogenous IGF-1 signal. |
| Ipamorelin | 100 mcg | Pre-bed, paired with CJC-1295 | Selective secretagogue completing the GHRH + GHRP pairing. |
- Cycle
- 4 weeks on, 4 weeks off — non-negotiable, receptors downregulate
- Timing
- IGF-1 LR3 around the training session; GH pair pre-bed
- Route
- Subcutaneous, rotating sites
- Food
- Have carbohydrate available after an IGF-1 LR3 dose — hypoglycemia is the real acute risk
- Prerequisite
- Baseline fasting glucose and HbA1c before the first injection
Who this stack suits
Best for
- Experienced lifters with years of training age and a plateau that is not a programming problem
- People already running clean bloodwork with a clinician in the loop
Not for
- Beginners and intermediates — this will not outperform fixing your programme, protein and sleep
- Anyone with diabetes, reactive hypoglycemia or unstable blood sugar
- Anyone with a personal or family cancer history; IGF-1 signalling is directly implicated in cell proliferation
What the evidence says
Why IGF-1 LR3 is different
The LR3 modification blocks binding to IGF-binding proteins, which extends the analog's active half-life from minutes to many hours. That is what makes it potent and also what makes the risks real: the signal stays switched on far longer than natural IGF-1 does, including its effect on glucose uptake.
Human evidence is essentially absent
There are no controlled trials of IGF-1 LR3 for hypertrophy in healthy trained adults. Recombinant IGF-1 (mecasermin) is an approved drug for severe IGF-1 deficiency in children, and its documented adverse-event profile — hypoglycemia above all — is the best available guide to what the analog does in people.
The cycling rule is the protocol
Every version of this stack that circulates caps the on-period at around four weeks. The stated reason is receptor downregulation: run it longer and the same dose does progressively less while the metabolic risk stays constant. Extending the cycle is the most common mistake made with this compound.
Risks and side effects
- None of these compounds are FDA-approved for muscle building, all are WADA-banned in competition, and research-chemical sourcing means purity is never guaranteed.
- Hypoglycemia is the acute danger — shakiness, sweating, confusion after a dose means eat carbohydrate immediately.
- IGF-1 signalling drives cell proliferation of all kinds, which is why any cancer history rules this out.
- Joint pain, water retention and numbness in the hands indicate the dose is too high.
- Research-chemical supply means the actual concentration in a vial is unverified — a dosing error here is a glucose emergency, not a wasted week.
Monitoring
Bloodwork to run
- Fasting glucose, HbA1c and fasting insulin before starting and again at the end of each cycle
- IGF-1 at baseline and mid-cycle
- Comprehensive metabolic panel and CBC each cycle
What to track in DoseRoutine
- Every dose with the time and whether it was pre- or post-training
- Any hypoglycemia symptom, with the time it occurred relative to the dose
- Weight, waist and training loads weekly — so the four weeks produce a real answer
Frequently asked
- How much IGF-1 LR3 do people use?
- Circulating protocols sit at 20–50 mcg per day, taken around the training session, for a maximum of four weeks before a four-week break. There is no clinical trial behind those numbers in healthy adults — they come from community practice, and the low end is where anyone considering this should start.
- Why can't you run IGF-1 LR3 longer than four weeks?
- Because receptor downregulation blunts the response while the metabolic risk does not go away. Past roughly four weeks people report that the same dose does progressively less, so they raise it, which raises the hypoglycemia risk without buying back the effect. The four-week cap exists to stop that spiral.
- Is IGF-1 LR3 dangerous?
- It carries the most serious acute risk of any compound on this page. Hypoglycemia can come on fast after a dose, and because the LR3 form stays active for hours, the window is long. Add the proliferative concern — IGF-1 signalling is implicated in tumour growth — and this is a compound that should not be used without a clinician and current bloodwork.
- Is this better than just running CJC-1295 and ipamorelin?
- Not for most people. The GH pulse stack works with your own pituitary and has a far gentler risk profile. IGF-1 LR3 is the option experienced lifters add when everything else is already dialled in, and it trades a modest additional signal for a genuinely different level of risk.
Compounds in this stack
Full monographs with doses, evidence quality, interactions and sources.
Other stacks
Keep exploring
Last reviewed 2026-09-22.