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✔Evidence basedThis article is reviewed by medical professionals for the relevancy and accuracy of the content. Every article is evidence-based and contains references to peer-reviewed studies and academic research.Peptides are some of the most popular performance-enhancing drugs amongst athletes and bodybuilders who look for potent options for muscle growth and fat-burning.
However, most of these products are illegal for use because their safety and effectiveness are poorly researched.
One such peptide is LR3 IGF-1, also known as “Long R3 IGF-1”.
It is a synthetic version of the hormone insulin-like growth factor 1, which is an anabolic hormone that is naturally found in the human body, and its levels depend on the production of growth hormone.
IGF-1’s primary function is to mediate the anabolic effects of the hGH and plays a major role in growth regulation in children.
Long R3 IGF-1 is modified to help increase its potency and stability while still exerting anabolic effects similar to IGF-1
“Long” stands for the additional 13 amino acids added to the N-terminus of the peptide molecule, while “R3” describes the replacement of the 3rd amino acid in the native hormone with arginine.
Athletes and bodybuilders use it illegally because of promises of increased muscle mass, improved physical performance, and faster tissue recovery time after injuries.
However, IGF-1 LR3 was never intended for human use, and clinical research regarding its effects or safety is lacking. Due to these safety concerns and the uncertain results, it is best to abstain from taking poorly studied products.
In this article, you will discover more about the research regarding Long R3 IGF-1 and whether the risk of side effects is worth any potential benefit.
What is IGF-1 LR3?
IGF-1 and its modified synthetic versions such as Long R3 IGF-1, des(1-3)IGF-1, and R3-IGF-I, have mitogenic effects, which speed up cell replication in laboratory models of different tissues.
IGF-1 LR3 was developed as a more potent version of insulin-like growth hormone-1, as it has better stability and efficiency for stimulating cell growth during in vitro experiments.
Adding this peptide to cell culture speeds up cell division, which shortens the time to conduct laboratory research compared to the standard version of insulin-like growth factor 1.
IGF-1 LR3 achieves this by activating the insulin-like growth factor 1 receptors found in most human and animal cells. Activating these anabolic receptors leads to increases in protein synthesis and tissue growth.
Difference between IGF-1 and IGF-1 LR3
Most of the natural hormone insulin-like growth factor 1 that is found in your body binds to serum proteins called IGF-binding proteins (IGFBPs). This prolongs its half-life by up to 15 hours but reduces the affinity to the insulin-like growth factor 1 receptors.
In comparison, the IGF1-LR3 peptide analog appears to have a higher affinity to the anabolic insulin-like growth factor 1 receptors and binds less to serum proteins.
As a result, this research peptide has enhanced potency, and animal studies report thatcontinuous infusion with LR3 IGF-1 had up to 2-fold higher anabolic effects than insulin-like growth factor 1. Tested animals experienced higher weight gain and increased weight of some of their organs (organomegaly).
The Half-Life of IGF-1 LR3
Currently, there is no clinical evidence reporting of insulin-like Growth Factor LR3 half-life in the human body.
Yet, the common belief shared on the Internet is that as a more stable version, IGF-1 LR3 has a longer half-life than that of traditional insulin-like growth factor-1. appear to be unsubstantiated.
As a reference, recombinant IGF-1 injections have a half-life of under 6 hours when given subcutaneously as a treatment of growth failure and slower development of children due to poor IGF-1 levels.
In fact, LR3 IGF-1 is most likely eliminated quite fast when administered in vivo due to the fact that it binds less to serum proteins such as IGFBPs.
Indeed, studies in mice report that IGF-1/ LR3 is eliminated entirely within 4 hours of intramuscular injection, meaning its half-life in mice is less than 1 hour. The metabolites of IGF-1 LR3 had a slightly longer half-life and were detectable for up to 16 hours after the injection.
IGF-1 LR3 Dosage
IGF1-LR3 peptide is available as a sterile filtered white lyophilized (freeze-dried) powder that must be reconstituted with distilled water and used for research purposes only. The vial sizes range from 0.2 to 1 mg.
For research purposes, the vial must be reconstituted with 2-10 ml of sterile water until achieving a concentration of 0.1 mg per milliliter. Afterward, the solution should be stored in a refrigerator at 4°C for 2-7 days.
However, scientists and health experts in general have not determined an effective or safe dosage for IGF-1 LR3 outside laboratory settings.
Nevertheless, athletes and bodybuilders often purchase the product illegally and administer it subcutaneously in an attempt to boost muscle protein synthesis.
According to unofficial sources, the most common IGF-1 LR3 dosage when used as a performance-enhancing drug ranges from 0.2 to 1 mg per day.
These suggestions for dosage are much lower compared to the officially recommended doses for human recombinant insulin-like growth factor 1, which is also available as a medication for patients with IGF-1 deficiency.
These patients take 0.04 – 0.12 mg/kg of insulin-like growth factor 1 twice daily subcutaneously, which is equal to at least 5.6 mg of the hormone per day for a 70 kg person.
Despite the fact that IGF-1 LR3 is an analog with 2-3 times higher potency and purportedly longer half-life, it is unlikely that taking it in doses more than ten times lower than insulin-like growth factor 1 may provide any noticeable effects.
IGF-1 LR3 Administration
Due to the lack of data from clinical research and the fact that IGF-1 LR3 is not an approved amino acid analog of insulin-like growth factor 1 for human use, there are no official recommendations on how and where to inject it.
Considering that the peptide is an analog of insulin-like growth factor 1, athletes and bodybuilders use it in a similar fashion, mainly by injecting it subcutaneously once or twice a day.
Insulin-like growth factor 1 and its analogs are most bioavailable when injected because they are not reliably absorbed through the digestive system or skin.
The subcutaneous route is generally considered the preferred method for administering peptides such as insulin-like growth factor 1 because it provides slower release and increased half-life of the medication compared to injecting them intramuscularly.
Most individuals who abuse IGF-1 LR3 as a performance-enhancing drug take it once a day for 6-7 weeks, usually right before or after a workout, and then cycle it off for at least a couple of weeks. However, there is no research to substantiate such a dosing regime or a dosage cycle.
What Results Can You Expect?
In terms of effects, animal research reveals that administering IGF-1 LR3 has a similar mechanism of action as its natural counterpart and it helps protect against muscle mass loss and catabolism during reduced periods of energy intake.
The IGF1-LR3 peptide was infused for 8 hours, significantly suppressing the natural IGF-1 production.
Continuous infusion may be tested for its potential to increase nitrogen retention and reduce loss of muscle due to conditions such as muscle-wasting diseases.
Yet, there is no clinical research reporting on its effects on humans, so there is no guarantee it will work the same way or play any role in the growth of muscle and strength.
Most importantly, IGF-1 LR3 is not meant for human use and can be legally obtained only for research purposes.
It is unclear how long it may take until there are any health benefits of IGF-1 LR3 when used in vivo.
According to animal research, the potential health benefits of IGF-1 LR3 are limited, because insulin-like growth factor 1 and its analogs possess only the anabolic effects and lack the fat-burning properties of growth hormone.
However, the Internet is filled with unsubstantiated claims that the peptide can cause unique and proven benefits such as:
- Improvements in muscle mass and muscle building
- body fat loss and reduced body weight
- improved body appearance
- faster recovery from injuries
- improved energy levels
- better physical performance
- increased ligament strength
- better muscle recovery after workouts
- improved cognition
- Improved bone density
- tissue regenerative properties
The only plausible health benefits supported by any research are those observed in test animals, including reduced muscle damage during activity, muscle-sparing effects, increased organ growth, and weight gain.
Moreover, some in vivo studies show that the peptide may actually reduce growth in tested animals due to the suppressive effect of this research peptide on the natural production of growth hormone.
Therefore, the research regarding the effects of LR3 version remains preliminary and mostly controversial, with no guarantee that the peptide can cause any actual muscle growth.
What Are the IGF-1 LR3 Side Effects?
A prominent and potentially life-threatening health risk of taking IGF-1 LR3 is hypoglycemia. Hypoglycemia is a term that describes dangerously low blood sugar, which manifests with shaking, sweating, dizziness, hunger, confusion, and loss of consciousness.
The drop in blood glucose levels occurs due to the similarity between insulin and insulin-like growth factor-1 or its analogs. IGF1-LR3 targets insulin receptors and stimulates glucose uptake inside body cells, similar to all other analogs. This can lead to a crash in blood glucose levels and hypoglycemia.
Initial studies also report that IGF-1 LR3 may lead to the growth of mucosa inside the intestines. This unwanted side effect occurs mainly due to an increase in the number of mucosal cells in the small intestine.
As a result, this research peptide may, at least in theory, lead to an enlargement of the intestines and “bubble gut,” similar to those observed in bodybuilders who abuse human growth hormone injections.
As mentioned, the peptide may also act as a negative stimulus of growth hormone production, based on preliminary studies. It is unknown whether the IGF-1 LR3 side effects can lead to the development of growth hormone deficiency or long-term health problems such as cardiovascular disease.
Currently, there is not enough evidence to report more potential LR3 IGF-1 side effects. It is unclear whether the peptide may affect insulin resistance, water retention, joint pain, or muscle pain which are usually related to hGH abuse.
Considering the similarities between insulin-like growth factor-1 and this research peptide, you may expect similar adverse reactions for this analog. For example, studies on insulin-like growth factor 1 report that it is not associated with increased insulin resistance.
Unfortunately, IGF-1 LR3 may lead to other adverse reactions similar to those related to insulin-like growth factor 1, like stimulating the growth of existing tumors, acromegaly, and organ enlargement. Unregulated substances that are not meant for human use, including IGF-1 LR3, can also have unknown or potentially debilitating side effects.
Is IGF-1 LR3 Better Than HGH?
Athletes and bodybuilders purchase the product on the black market, hoping it will be an even better solution for muscle growth enhancement than taking insulin-like growth factor 1 or hGH.
Compared to IGF-1 LR3, growth hormone therapy has been studied much more extensively, and a considerable amount of evidence supports its effectiveness in increasing lean muscle mass and improving quality of life.
In fact,growth hormone injections promote anabolic effects in muscle tissue while also stimulating fat breakdown. Insulin-like growth factor 1 and its analogs are capable of mediating only the anabolic effects of hGH.
Growth hormone injections also have well-known side effects such as increased retention of water, which can be easily avoided by correcting the dose of the medication. In comparison, IGF-1 LR3 is not studied in humans, and there is a risk of dangerous side effects.