IGF-1 LR3 is a chemical naturally formed by the organism. IGF 1 Long R3 is a polypeptide amino acid. Naturally, human growth hormone is turned into IGF 1 to eliminate excess glucose throughout the body. This peptide aims to work the same way when administered on test subjects during experiments.

IGF-1 LR3 is just an extended analogue of IGF-1, and is a synthetic protein. The difference between this and the original IGF-1 is that, instead of glutamic acid, LR3 contains arginine at the 3rd position of its amino sequence – hence R3. It also has thirteen more amino acids at its N-terminus, making it much longer, for a combined total of eighty-three aminos, compared to the seventy that come with IGF-1 alone.

Researchers have reported the potency of IGF-1LR3 to be about 3 times more than that of IGF-1 [1], and it holds a significantly greater half-life – roughly twenty to thirty hours, compared to the original IGF-1, which has only about twelve to fifteen hours of half-life.

IGF-1 LR3 vs LR2

Though molecularly and structurally alike, IGF-1 LR3 should not be confused with LR2. The main difference between the two is that IGF-LR3 is primarily found in adult organisms, while LR2 presents itself more in younger organisms whose bodily systems are still undergoing development. This is one way to understand why IGF-1 significantly affects muscle tissue growth and repair. The IGF 1-LR3 peptide was developed for long-term research to closely study its potential ability to prevent the deactivation of binding proteins within the blood [2].

IGF-1 LR3 Research

IGF-1 LR3 has been reported to exhibit multiple possible properties in various studies. Its primary properties include its potential to increase lipolysis, aiding in weight loss, promote protein synthesis and muscle recovery.

IGF-1 LR3 and Weight Loss

IGF-1 LR 3 may boost energy metabolism efficiency by inducing cells to become more sensitive to insulin, while at the same time elevating the fat catabolic rate. This is a metabolic process through which energy is released as fat is broken down into smaller, more easily manageable compounds. This is all done to fuel important cellular processes. It boosts the metabolism of fat in muscle tissue, while also up-regulating protein synthesis in muscle cells (individually) and preserving glucose at the same time. The final result, then, is muscle growth due to increases in the size of the cell. Atop the muscle gains, studies have also suggested the peptide’s potential to lower the body’s general fat content.

IGF-1 LR3 and Muscle Growth

One study aimed to investigate IGF-1 LR3 peptide’s effects on the metabolism of protein. The non-human animal subjects used in this study were underfed on purpose, so that they lose weight. The subjects were divided into a test group (who were administered the peptide intravenously) and the control group (who did not receive the substance). The results observed that the animals in the test group were able to preserve protein in both their skeletal muscles and the body as a whole. Recent studies have presented IGF-1’s role as a moderator of GH effects. Therefore, it is implied that whatever IGF-1 does affects the majority of the body’s cells. Again, IGF-1 is produced at its highest levels usually throughout puberty, which is why the young organism undergoing this process experiences both significant muscle growth and a growth spurt in height.

IGF-1 LR3 Mechanism of Action

IGF-1 LR3 may be a significant (hormonal) moderator of statural growth. Usually, in the liver as well as in other tissues, growth hormone sticks to its receptor and promotes IGF-1 secretion and synthesis. In particular tissues, the IGF (type 1) receptor that corresponds to the insulin receptor has been reported by researchers to be activated by IGF-1 LR3 which may induce intracellular communication, promoting various processes resulting in the growth of the organism’s stature. The metabolic actions of IGF-1 LR3 are aimed partially at promoting the uptake of fatty acids, amino acids, and glucose so that developing tissues are supported by their metabolism. Their efficacy and the peptide’s full mechanism of action requires further validation and remains under investigation.

IGF 1 LR3 Side Effects

With all research substances, there comes the possibility of adverse effects. Particularly in the case of IGF-1 LR3 side effects, researchers report that adverse effects may be similar to those of human growth hormone (HGH) [3]:

  • Drop in blood sugar
  • Overgrowth of body tissue
  • Skin sensitivity at injection site
  • Liver damage

These side effects, however, are much less likely to be experienced if the substance is responsibly administered by the researcher on the test subjects.

Researchers can find IGF-1 LR3 for sale online, but it’s best to use a trusted source. Researchers can buy Receptor Grade IGF-1 LR3 and other high quality peptides and peptide blends for research by visiting the Core Peptides online store. The peptide is available strictly for research and laboratory purposes only.



  1. Tomas M, et al. “Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection.” 1996.
  2. Oliver T., et al. “The local expression and abundance of insulin-like growth factor (IGF) binding proteins in skeletal muscle are regulated by age and gender but not local IGF-I in vivo.” 2005
  3. Anderson, J., et al. “Use of growth hormone, IGF-I, and insulin for anabolic purpose: Pharmacological basis, methods of detection, and adverse effects.” 2018.



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