IGF-1 LR3, also called Long R3 IGF-1 or Long-(Arg3)-IGF-I, is a modified analogue of insulin-like growth factor-1 that has been studied primarily in laboratory and preclinical research. It should not be confused with FDA-approved mecasermin, which is recombinant human IGF-1 rather than Long R3 IGF-1.
There is no scientifically established universal BAC-water volume for IGF-1 LR3. The resulting concentration is determined mathematically by the quantity of compound divided by the liquid volume; the examples below are concentration calculations only.
There is no universal scientifically established BAC-water volume for IGF-1 LR3. A different liquid volume produces a different concentration while the total amount of peptide in the vial remains unchanged.
For example, a hypothetical 5 mg quantity would mathematically equal 5 mg/mL in 1 mL, 2.5 mg/mL in 2 mL, and 1 mg/mL in 5 mL. These are calculations, not instructions for preparing or administering IGF-1 LR3.
The quantities below are mathematical examples selected to demonstrate the concentration formula. They should not be interpreted as standardized commercial IGF-1 LR3 vial sizes.
| Illustrative Vial Quantity | 1 mL | 2 mL | 2.5 mL | 3 mL | 5 mL |
|---|---|---|---|---|---|
| 1 mg | 1 mg/mL | 0.5 mg/mL | 0.4 mg/mL | 0.333 mg/mL | 0.2 mg/mL |
| 5 mg | 5 mg/mL | 2.5 mg/mL | 2 mg/mL | 1.667 mg/mL | 1 mg/mL |
| 10 mg | 10 mg/mL | 5 mg/mL | 4 mg/mL | 3.333 mg/mL | 2 mg/mL |
The scientifically defensible answer is that no single BAC-water volume can be presented as a universal IGF-1 LR3 instruction. The required liquid volume depends on the starting quantity and the target concentration being modeled.
If a research material certificate, manufacturer documentation, institutional protocol, or validated laboratory procedure specifies a concentration or preparation method, that source should take precedence over generic internet protocols.
Mathematically, 5 mg divided by 1 mL equals 5 mg/mL; 5 mg divided by 2 mL equals 2.5 mg/mL; and 5 mg divided by 5 mL equals 1 mg/mL.
These are concentration calculations only and do not establish a preferred preparation volume.
Mathematically, 10 mg divided by 1 mL equals 10 mg/mL; 10 mg divided by 2 mL equals 5 mg/mL; and 10 mg divided by 5 mL equals 2 mg/mL.
The appropriate preparation, if any, must come from an authoritative product or research protocol rather than from this mathematical example.
With a fixed amount of peptide, increasing the liquid volume decreases the concentration. Decreasing the liquid volume increases the concentration. The total mass of peptide represented by the vial does not change simply because the liquid volume changes.
IGF-1 is a peptide growth factor involved in growth, development, metabolism and tissue signaling. Long R3 IGF-I is a modified IGF-I analogue designed with structural changes that alter interactions with IGF-binding proteins.
Experimental work has investigated Long R3 IGF-I in cellular and animal systems, including studies of biological potency and pharmacokinetic or analytical behavior. These findings should not be automatically interpreted as evidence of an established human therapeutic effect.
IGF-1 LR3, commonly written as Long R3 IGF-1 or Long-(Arg3)-IGF-I, is a modified analogue of insulin-like growth factor-I (IGF-I).
The “R3” designation refers to an arginine substitution at position 3, while “Long” refers to an N-terminal extension. These structural changes influence how the analogue interacts with IGF-binding proteins and biological systems.
Experimental literature has reported altered binding and biological potency compared with native IGF-I in selected experimental models.
Native recombinant human IGF-1 is represented clinically by mecasermin (INCRELEX). FDA labeling identifies mecasermin as recombinant human IGF-1 and gives its approved pediatric indication.
IGF-1 LR3 is a different modified analogue. The existence of an FDA-approved IGF-1 product therefore does not mean that IGF-1 LR3 is FDA-approved.
IGF-I participates in a growth-factor signaling system that includes the type 1 IGF receptor (IGF-1R) and several IGF-binding proteins. Experimental modifications to IGF-I can change the balance between receptor activity and binding-protein interactions.
Long R3 IGF-I has been used as an experimental analogue for studying IGF signaling, protein synthesis and growth-related cellular responses.
Laboratory research has examined IGF-I analogues in cultured cells to compare receptor signaling, biological potency and interactions with IGF-binding proteins.
Long R3 IGF-I has also been evaluated in animal models, including studies of biological activity and metabolism.
Long R3 IGF-I has been investigated analytically because IGF-I analogues are prohibited in sport and require specialized detection methods.
The human evidence base for IGF-1 LR3 is substantially different from the evidence base for FDA-approved recombinant human IGF-1. A PubMed-indexed analytical study specifically examining Long R3 IGF-I states that IGF-I analogues including Long R3 IGF-I were not approved for human use and describes their detection in biological samples.
The available literature reviewed for this page does not establish a clinically validated human dosing regimen for IGF-1 LR3.
The published literature identified for Long R3 IGF-I is dominated by laboratory, analytical and animal research rather than established human therapeutic trials. Consequently, a human clinical dose table cannot responsibly be populated with a recommended IGF-1 LR3 dose.
| Study / Evidence | Model | Exposure | Route / Method | Purpose | Interpretation |
|---|---|---|---|---|---|
| Thomas et al., 2017 | Human plasma analytical research + laboratory metabolism | Analytical detection of Long R3 IGF-I and metabolites | LC-MS / biological samples | Detection and characterization | Not a therapeutic efficacy or dosing study. |
| Mongongu et al., 2021 | Rats + in-vitro human blood experiments | Experimental administration and analytical detection | Rat administration; analytical laboratory methods | Anti-doping detection and metabolite characterization | Preclinical/analytical evidence, not a human dosing recommendation. |
| McCusker et al. / IGF analogue research | Experimental animal/cellular models | Model-specific experimental concentrations | Laboratory / animal models | IGF binding, potency and biological activity | Results cannot be directly converted into human dosing. |
Experimental studies have compared Long R3 IGF-I with native IGF-I in cellular models. Reduced association with some IGF-binding proteins can change the amount of biologically available peptide in an experimental environment.
Some cell systems have demonstrated greater apparent biological potency for LR3 IGF-I than native IGF-I under particular experimental conditions.
Animal research has examined the biological activity, metabolism and physiological effects of IGF-I analogues. Long R3 IGF-I has also been used in analytical studies involving rodents.
Animal findings are useful for hypothesis generation but cannot establish human efficacy, safety or an appropriate human dose.
Concentration is calculated by dividing the total quantity of compound by the final liquid volume:
Example: if a hypothetical research sample contains 5 mg and the mathematical liquid volume is 2 mL:
This equation describes concentration only. It does not establish that 2 mL is an appropriate preparation volume for an actual IGF-1 LR3 product.
BAC water is a type of bacteriostatic diluent. However, the fact that a diluent exists does not establish that a particular research peptide has a validated universal BAC-water preparation protocol.
For IGF-1 LR3, this distinction is especially important because authoritative sources reviewed for this page do not establish a universal BAC-water volume for a standardized LR3 research vial.
FDA records show that INCRELEX (mecasermin) is an approved recombinant human IGF-1 product. Its current labeling specifies an indication for growth failure in pediatric patients with severe primary IGF-1 deficiency or certain GH-gene-related conditions.
The FDA label describes mecasermin as recombinant human IGF-1, not Long R3 IGF-I.
FDA's substance database identifies Long-(Arg3)-insulin-like growth factor-I and lists IGF-1 LR3 and Long R3 IGF-I as synonyms.
Identification of a substance in an FDA database does not mean that the substance has been reviewed or approved as a drug.
If you need to model a different quantity or liquid volume, use the BacScience BAC Water Calculator rather than manually estimating the result.
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