Side-by-side · Research reference
IGF-1 LR3vsSermorelin
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AAnimal-StrongHUMAN-REVIEWED10/58 cited
BPhase 3HUMAN-REVIEWED14/43 cited
IGF-1 LR3
IGF-1 Analogue · Research
3–10×Potency vs IGF-I
Low IGFBPBinding affinity
ResearchStatus
Research only · SQ typical in animal models
Sermorelin
GHRH 1-29 fragment · Short-acting
SQ · Pre-sleep · 1×/day
01Mechanism of Action
Parameter
IGF-1 LR3
Sermorelin
Pathway
IGF-1R → IRS-1 → PI3K/Akt → Cell proliferation, protein synthesis, anti-apoptosisMuhlbradt 2009
GHRH-R → Gαs → cAMP → PKA → GH vesicle exocytosisWalker 1994
Downstream effect
Enhanced cell proliferation, muscle anabolism, inhibition of apoptosis, increased telomerase activity
Pulsatile GH release; subsequent IGF-1 elevationMolteno 2013
Feedback intact?
No — exogenous IGF analogue bypasses GH-mediated regulation
Yes — short pulse preserves feedback
Origin
Synthetic 83-AA analogue: 13-AA N-terminal extension + Arg substitution at position 3
Unmodified active 29-AA fragment of human GHRH (1-44)Walker 1994
Antibody development
—
—
02Dosage Protocols
Parameter
IGF-1 LR3
Sermorelin
Research dose (animal models)
Variable by protocol and species
In vivo murine atherosclerosis studies used sustained delivery.
—
In vitro typical concentration
10–1000 ng/mLThomas 2007
Dose-dependent effects on follicle growth and estradiol production.
—
Half-maximal stimulation
0.6 nM LR3 vs 1.5 nM native IGF-1Price 2004
2.5-fold greater potency in lung fibroblast proliferation.
—
Evidence basis
Animal / in vitro only
Phase 3 (Geref pediatric); clinical practiceWalker 1994Molteno 2013
Human use
Not FDA-approved; no published human trials
—
Frequency
—
Once daily, pre-sleep
Lower / starter dose
—
100 mcg per dose
Duration
—
8–12 weeks per cycle
Reconstitution
—
Bacteriostatic water
Timing
—
Pre-sleep, fasted preferred
03Metabolic / Fat Loss Evidence
Parameter
IGF-1 LR3
Sermorelin
Mechanism
IGF-1R activation → lipolytic signaling; secondary to anabolic effects
—
Direct lipolytic evidence
Minimal — primarily anabolic/anti-apoptotic in literature
—
Atherosclerotic plaque effects
Reduced stenosis and core size in ApoE-KO micevon 2011
Plaque stabilization via vSMC phenotype modulation, not direct fat loss.
—
Human data
None published
—
04Side Effects & Safety
Parameter
IGF-1 LR3
Sermorelin
Hypoglycemia risk
Theoretical — IGF-1 analogues can lower blood glucose
—
Excessive cell proliferation
Mitogenic signaling; theoretical tumor promotion risk
—
Telomerase activation
2–10-fold increase in prostate cancer cells (PC-3, DU-145, LAPC-4)Wetterau 2003
Critically involved in cancer cell immortalization.
—
Oocyte degeneration
Increased oocyte degeneration at high doses (≥1000 ng/mL) in bovine folliclesThomas 2007
—
Unregulated anabolism
Bypasses physiological GH/IGF-1 feedback; no pulsatility control
—
Unknown human safety profile
No published human trials; safety data absent
—
Injection site reaction
—
Mild erythema, transient pain
Flushing / headache
—
Common transient effect
IGF-1 elevation
—
Modest at standard doses
Cancer risk
—
Contraindicated in active malignancy (GH/IGF-1 axis)
Pregnancy / OB
—
Avoid
Glucose handling
—
Generally neutral
Absolute Contraindications
IGF-1 LR3
- ·Active malignancy or history of cancer
- ·Not approved for human use
Sermorelin
- ·Active malignancy
- ·Pregnancy / breastfeeding
- ·Disrupted hypothalamic-pituitary axis
Relative Contraindications
IGF-1 LR3
- ·Diabetes or glucose intolerance
- ·Family history of cancer
Sermorelin
- ·Untreated diabetes
05Administration Protocol
Parameter
IGF-1 LR3
Sermorelin
1. Research use only
IGF-1 LR3 is not FDA-approved for human use. All administration data derives from animal or in vitro studies.
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.
2. Typical research route
Subcutaneous or intraperitoneal injection in animal models. In vitro: added directly to culture medium at concentrations of 10–1000 ng/mL.Thomas 2007
SQ — abdomen or thigh. Rotate sites.
3. Reconstitution (research)
Lyophilised powder reconstituted in sterile water or buffered saline per manufacturer protocol. Store at 2–8 °C after reconstitution.
Pre-sleep, fasted.
4. Stability
Enhanced stability vs native IGF-1 due to reduced IGFBP binding; exact half-life in vivo not fully characterized in humans.
Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.
5. Needle
—
29–31G, 4–8 mm insulin syringe.
06Stack Synergy
IGF-1 LR3
+ GHRP-6
Multi-pathwayGHRP-6 stimulates endogenous GH release, which drives hepatic IGF-1 synthesis. IGF-1 LR3 provides exogenous, IGFBP-resistant IGF signaling. Combining upstream GH stimulation with downstream IGF receptor activation creates a dual-pathway anabolic effect. However, this bypasses natural feedback and carries compounded mitogenic risk.
- GHRP-6
- 100–200 mcg SQ · 2–3× daily
- IGF-1 LR3
- Research doses variable · post-workout typical in animal models
- Note
- Research context only — no human protocols exist
- Primary benefit
- Theoretical maximal anabolic signaling (GH + IGF axes)
+ Ipamorelin
Multi-pathwayIpamorelin (selective GHRP) stimulates pulsatile GH release without cortisol/prolactin elevation. IGF-1 LR3 directly activates IGF-1R independent of GH. This stack targets both upstream (GH secretion) and downstream (IGF receptor) nodes but eliminates physiological feedback, raising safety concerns around unchecked proliferation.
- Ipamorelin
- 200–300 mcg SQ · evening
- IGF-1 LR3
- Research doses only · timing variable
- Caution
- No human data; animal/in vitro only
- Primary benefit
- Dual-axis anabolic signaling (theoretical)
Sermorelin
+ Ipamorelin
StrongSermorelin (GHRH analogue) and ipamorelin (selective GHRP) form the prototypical GHRH+GHRP dual-axis stack at the lowest cost. Both peak within 30 min and produce a sharp physiological GH pulse without cortisol/prolactin elevation.
- Sermorelin
- 200–300 mcg SQ · pre-sleep
- Ipamorelin
- 200–300 mcg SQ · same injection
- Primary benefit
- Pulsatile GH stimulation, recovery, body composition