IGF-1 LR3
Also known as: IGF-1 LR3, Long R3 IGF-1, Receptor Grade IGF-1 LR3
IGF-1 LR3 (Long R3 IGF-1) is an engineered, long-acting analog of insulin-like growth factor 1 studied for sustained anabolic and tissue-growth signaling. Its modifications give it a far longer half-life than native IGF-1.
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Mechanism of Action
IGF-1 LR3 carries an arginine substitution at position 3 plus a 13-amino-acid N-terminal extension, which sharply reduce its affinity for IGF-binding proteins and extend its circulating half-life. With prolonged availability of free peptide, it strongly and persistently activates the IGF-1 receptor (IGF-1R) tyrosine kinase, driving PI3K/Akt/mTOR and Ras/MAPK signaling that promotes protein synthesis, cell proliferation, and inhibition of apoptosis. This produces systemic, sustained anabolic effects in research models.
- Half-life
- Substantially extended versus native IGF-1; commonly cited around 20 to 30 hours
- Administration Routes
- subcutaneous
- Research Status
- Research Chemical
Reported Benefits
- Long-acting, sustained IGF-1 receptor activation
- Promotes muscle protein synthesis and hypertrophy
- Supports cell proliferation and tissue repair
- Resists binding-protein sequestration for greater free activity
- Studied for recovery and body-composition endpoints
Potential Side Effects
- Hypoglycemia from insulin-like activity
- Injection-site reactions
- Possible organ or tissue overgrowth with chronic use
- Headache or lethargy
- Limited human safety data
Common Dosing
Research-use only, not medical advice. The literature references small subcutaneous amounts (often tens of micrograms per administration); because of its long action it is studied at lower frequency than short-acting IGF-1 forms.
The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.
Contraindications
- Active or suspected malignancy
- Unstable blood glucose or hypoglycemia risk
- Pregnancy or breastfeeding
IGF-1 DES
IGF-1 DES is a truncated variant of insulin-like growth factor 1 missing the first three N-terminal amino acids, studied for potent, localized anabolic and tissue-growth effects. It is noted for higher activity at the site of injection.
MGF (Mechano Growth Factor)
MGF is a splice variant of IGF-1 produced locally in muscle in response to mechanical loading or damage. It is studied for its role in activating muscle stem cells and supporting tissue repair.
PEG-MGF
PEG-MGF is a pegylated form of Mechano Growth Factor engineered for greater stability and a longer systemic half-life than native MGF. It is studied for muscle stem cell activation and recovery.
CJC-1295
A long-acting growth hormone releasing hormone (GHRH) analog that stimulates the pituitary to produce more growth hormone. Often paired with a ghrelin mimetic for synergistic GH release.
Ipamorelin
A selective ghrelin receptor agonist (growth hormone secretagogue) prized for stimulating GH release with minimal effect on cortisol or prolactin. Considered one of the gentler GH peptides.
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Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency
1992
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Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig
1995
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IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys
1997
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Detection of LongR(3) -IGF-I, Des(1-3)-IGF-I, and R(3) -IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes
2021