Peptide Comparison
IGF-1 LR3vsIpamorelin
A supercharged version of your body's own growth factor that stays active 2-3 times longer than regular IGF-1, making it a powerhouse for muscle growth, recovery, and cellular regeneration.
A uniquely selective growth hormone booster that tells your pituitary to release more GH without messing with your cortisol or other hormones—making it the 'clean' choice among growth hormone peptides.
At a Glance
Quick
comparison
Dose Range
IGF-1 LR3
20–100 mcg
Ipamorelin
200–200 mcg
Frequency
IGF-1 LR3
Once daily
Ipamorelin
Multiple times daily
Administration
IGF-1 LR3
Subcutaneous injection
Ipamorelin
Subcutaneous injection
Cycle Length
IGF-1 LR3
4-6 weeks
Ipamorelin
8-12 weeks
Onset Speed
IGF-1 LR3
Rapid (hours to days)
Ipamorelin
Moderate (1-2 weeks)
Evidence Level
IGF-1 LR3
Strong preclinical (extensive animal studies)
Ipamorelin
Moderate human trials (Phase 1-2)
Efficacy
Benefit
ratings
Muscle Growth
Recovery Speed
Nutrient Utilization
GH Selectivity
Recovery Support
Safety Profile
Technical Data
Compound
specifications
IGF-1 LR3
Molecular Formula
C400H625N111O115S9
Molecular Weight
9111.4 g/mol
Half-Life
20-30 hours
Bioavailability
High when injected subcutaneously or intramuscularly
CAS Number
946870-92-4
Ipamorelin
Molecular Formula
C38H49N9O5
Molecular Weight
711.85 g/mol
Half-Life
2 hours
Bioavailability
High when injected subcutaneously
CAS Number
170851-70-4
Protocols
Dosing
tiers
IGF-1 LR3
Ipamorelin
Applications
Best
suited for
IGF-1 LR3
Serious Muscle Builders
If you're pushing hard in the gym and want to maximize every rep, IGF-1 LR3 helps your muscles grow through both hypertrophy (bigger cells) AND hyperplasia (more cells) [2]. That's a one-two punch that few other compounds offer.
Recovery-Focused Athletes
Train hard, recover faster. IGF-1 LR3 accelerates tissue repair and reduces the time you need between intense sessions [14]. It's particularly valuable during high-volume training blocks or when preparing for competition.
Body Recomposition Goals
Looking to build muscle while losing fat? IGF-1 LR3 helps shuttle nutrients into muscle cells while improving how your body uses fat for fuel [8][15]. Combined with proper diet, it supports that lean, muscular physique.
Post-Injury Rehabilitation
IGF-1 is your body's natural repair signal. The LR3 version stays active longer, potentially helping injured tissues heal more completely [1][5]. Athletes recovering from muscle strains or tears may find it particularly beneficial.
Ipamorelin
Clean GH Boost Seekers
If you want the benefits of increased growth hormone without spiking cortisol or other stress hormones, Ipamorelin is uniquely selective. Unlike GHRP-2 or GHRP-6, it won't raise your cortisol levels even at doses 200 times higher than needed for GH release.
Recovery-Focused Athletes
Ipamorelin shines for athletes who want better recovery between training sessions. The GH boost helps repair muscle tissue faster, and since it doesn't mess with other hormones, you can use it consistently without the rollercoaster effects.
Anti-Aging Enthusiasts
Growth hormone naturally declines as we age, contributing to muscle loss, fat gain, and reduced vitality. Ipamorelin offers a gentle way to restore more youthful GH levels without the risks of actual HGH therapy.
Those Recovering from Steroid Use
Research shows Ipamorelin can help counteract the muscle and bone-weakening effects of glucocorticoid medications. If you've been on steroids for medical reasons, this peptide may help you rebuild what you've lost.
Safety Profile
Side
effects
IGF-1 LR3
Common
- Hypoglycemia (low blood sugar)
- Injection site reactions
- Water retention
- Headaches
Uncommon
- Joint pain or stiffness
- Numbness or tingling
Serious
- Severe hypoglycemia
Ipamorelin
Common
- Mild headache
- Injection site reactions
- Water retention
- Increased appetite
Uncommon
- Tingling in hands or feet
- Joint stiffness
Serious
- Allergic reaction
Research Status
Safety
& evidence
IGF-1 LR3
Evidence Level
Strong preclinical (extensive animal studies)
FDA Status
Research compound
Safety Overview
IGF-1 LR3 has been extensively studied in research settings and shows a predictable side effect profile when used responsibly. The primary concern is hypoglycemia, which is manageable with proper nutrition timing [7][9]. Long-term safety data in humans is limited since it's used as a research compound. Joint discomfort and water retention are generally mild and resolve when cycling off.
Contraindications
- xActive cancer or history of cancer
- xPregnancy or breastfeeding
- xDiabetic retinopathy or uncontrolled diabetes
- xKnown hypersensitivity to IGF-1 or related peptides
- xChildren and adolescents (can affect growth plates)
Ipamorelin
Evidence Level
Moderate human trials (Phase 1-2)
FDA Status
Research compound
Safety Overview
Ipamorelin's main selling point is that it raises growth hormone without raising cortisol or ACTH — two stress hormones that similar peptides do raise. That was shown in pigs, and it held even at doses more than 200 times higher than the amount needed to raise growth hormone [1]. It has not been checked in people. The two published human studies measured ipamorelin and growth hormone only; neither one assayed cortisol, ACTH or prolactin [2][3]. Most of what we know about safety in people comes from a single trial in patients recovering from bowel surgery. 114 people took part: 56 got ipamorelin through an IV for up to seven days, and 58 got a placebo. Most side effects were mild to moderate, and were the kind you would expect after surgery [3]. Serious problems happened at about the same rate in both groups — roughly 1 in 6 either way (17.9% on ipamorelin, 15.5% on placebo). But three things were more common on ipamorelin: low potassium in about 1 in 8 people versus about 1 in 30 on placebo (12.5% vs 3.4%), trouble sleeping in about 1 in 9 versus about 1 in 19 (10.7% vs 5.2%), and high blood sugar at discharge in about 1 in 7 versus about 1 in 12 (14.3% vs 8.6%) [6]. Two people taking ipamorelin died. Both had colon cancer surgery, and in both cases the surgical join in the bowel leaked afterward. Nobody on the placebo died. The FDA says it is unclear whether those deaths had anything to do with ipamorelin — but it pointed to them, along with the potassium and blood sugar differences, when it recommended in October 2024 against letting pharmacies compound ipamorelin [6].
Contraindications
- xActive cancer or history of cancer
- xPregnancy or breastfeeding
- xPituitary disorders or tumors
- xKnown allergy to peptide components
- xChildren and adolescents (growth plates still open)
Decision Guide
Which is
right for you?
Choose IGF-1 LR3 if...
- Muscle growth and hypertrophy
- Post-workout recovery
- Body recomposition
- Athletic performance enhancement
Choose Ipamorelin if...
- Muscle recovery and growth
- Anti-aging and vitality
- Body composition improvement
- Sleep quality enhancement