IGF-1 LR3

IGF-1 LR3 is a variant of IGF-1 with an extended amino acid chain (Long R3). This modification means that the molecule binds less strongly to the proteins that normally bind to IGF-1, resulting in it exhibiting a longer duration of action than standard IGF-1 in research.

Mechanism of action under investigation

IGF-1 is a growth factor involved in cell growth, cell division and tissue maintenance. In research, IGF-1 LR3 is used to study these signalling pathways, for example in cell culture. Its longer duration of action makes it practical for experiments in which a stable, sustained signal is required.

These mechanisms are based on in vitro and preclinical research and describe the research context; they do not represent proven effects in humans.

The ‘LR3’ designation refers to the specific modifications: an extended chain (Long) and a substitution at position 3 (R3). Together, these modifications ensure that the molecule is less likely to be captured by binding proteins and therefore remains active for longer during an experiment.

IGF-1 and its variants are among the most extensively studied growth factors in cell biology. IGF-1 LR3 is widely used in laboratories as a reagent in cell culture, precisely because of its stability and longer duration of action.

• Research focus: growth factor signalling and cell proliferation.
• Research focus: tissue and muscle biology (preclinical).
• Research focus: use as a stable reagent in cell culture.

Status and context

IGF-1 LR3 is not authorised as a medicinal product and is supplied solely as research material. In the context of sport, IGF-1 (and its variants) is on the World Anti-Doping Agency’s (WADA) Prohibited List. When using it as a reagent, always document its purity and batch number to ensure that experiments remain reproducible.

IGF-1 LR3 is valued as a cell culture reagent because it provides a consistent, long-lasting growth signal; this facilitates experiments in which cells are monitored over a longer period. The choice of a pure, well-characterised batch minimises variation between experiments and makes results more comparable.

Researchers sometimes combine IGF-1 LR3 with other growth factors in cell culture to study complex signalling pathways; in such cases too, a clean, pure batch is crucial to the reliability of the measurement.

IGF-1 LR3 is supplied as a lyophilised powder and reconstituted in the laboratory using bacteriostatic water. The steps below describe only the laboratory procedures for research purposes.

1. 1Allow the vial and the bacteriostatic water to reach room temperature.
2. 2Wipe the rubber stoppers of both vials with an alcohol wipe.
3. 3Allow the bacteriostatic water to run slowly down the side of the vial; do not direct it straight onto the powder.
4. 4Gently swirl the vial until everything has dissolved; do not shake.
5. 5Store the solution in the fridge and label it with the date and batch number.

You can find supplies such as bacteriostatic water, insulin syringes and alcohol wipes under ‘Lab & Accessories’. This is a laboratory instruction and does not constitute dosage advice for consumption.

Working with a sensitive protein

IGF-1 LR3 is a protein and is therefore sensitive to repeated temperature fluctuations. Work quickly during reconstitution, avoid vigorous shaking and store the solution immediately under refrigeration to minimise degradation.

Working accurately with reagents

Work with small, precise volumes and record the exact concentration; with a vial containing just 1 mg, even a slight deviation can make a difference to your experiment.

Store IGF-1 LR3 in a cool, dark place; as a protein, it is sensitive to heat and repeated thawing.

Practical storage tips

• Powder form: store in the freezer (-20 °C) to ensure long-term stability.
• After reconstitution: store in a cool place (2–8 °C) and use as soon as possible.
• Avoid repeated defrosting and refreezing; if necessary, divide into smaller portions.
• Make a note of the reconstitution date and the batch number.

Cool, stable storage is essential for maintaining the integrity of the protein.

Where possible, use chilled surfaces when handling the product to minimise degradation.