Long Chain IGF (LR3IGF-1)

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Long Chain IGF (LR3IGF-1)


Long Chain IGF (LR3IGF-1, IGF-1 LR3, Arginine IGF, Long Chain Arginine IGF) is an IGF-derivative that is in research use.

The chemical structure of the LR3IGF-1 differs from IGF-1 in that one amino acid of the IGF-1 amino acid chain is artificially changed and a 13 amino acid long peptide chain is added to the amino acid chain of the IGF-1. Thus, the LR3IGF-1 molecule has altogether 83 amino acids. The changes made to the LR3IGF-1 molecule make it stronger and the effect lasts longer than those of physiologic IGF-1.


Since it is an IGF-1 derivative, LR3IGF-1 is a doping substance according to the Decree 705/2002 that defines the doping substances that are to be regarded as doping substances referred to in Chapter 44, §16, Subsection 1 of the Penal Code. Long Chain IGF is not in medical use, and some of the preparations being sold have been fakes. Muscle mass builders are known to abuse LR3IGF-1. The purpose of its use is to grow muscle mass, have fat burn faster than normal, and to speed up the recovery from injuries.

Adverse effects

Long Chain IGF is researched by animal testing [1]. All of the adverse effects of LR3IGF-1 to people are not determined. Its adverse effects are probably similar to that of ordinary IGF-1 or mecasermin. Acute overdoses probably cause high-level hypoglycemia (decreased sugar content in the blood). This can lead to unconsciousness and death. Other adverse effects can be allergic reactions, headaches, cramps, nausea, increased intracranial pressure, increased growth of malignant tumors and excessive growth of heart muscle. Long-term use with oversized doses can cause acromegaly (excessive growth of gristles, forehead, nose, chin, hands and foots), heart muscle changes, and arrhythmias.

Timo Seppälä
Medical Director
The Finnish Antidoping Agency FINADA

[1] Gillespie, Merkel & Martin (1997): Effects of insulin-like growth factor-I and LR3IGF-I on regional blood flow in normal rats. Journal of Endocrinology 155(2): 351– 8.

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