# IGF-1 LR3

IGF-1 LR3 is a lab-made copy of insulin-like growth factor I (IGF-I), a natural hormone that carries growth signals. Scientists first described it in 1992 under the name Long [Arg3]-IGF-I. This hub explains, in plain English, what it is, how it works in cells, what animal studies found and what the records say. Every answer comes from published studies, trial registries and regulator documents, and the hub says plainly where no human study was found.

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| Common name | IGF-1 LR3 |
| Full name | Long [Arg3] insulin-like growth factor I (Francis et al., 1992) |
| Change from native IGF-I | Glutamic acid at position 3 replaced by arginine, plus an N-terminal extension (Francis et al., 1992) |
| Native IGF-I length | 70 amino acids (FDA label for mecasermin, which matches human IGF-1) |
| Foundational cell paper | 1992 |
| Registered human trials, checked 16 October 2026 | None found on ClinicalTrials.gov for four search phrases |
| Human half-life | Not established in the sources opened |
| Poisons Standard, October 2026 | No individual entry; class entry INSULIN-LIKE GROWTH FACTORS, reach not established |
| WADA 2026 Prohibited List | S2.3 names IGF-1 and its analogues; prohibited at all times |

## Articles in this hub

- [How does IGF-1 LR3 work? Binding proteins, the IGF-1 receptor and what cells showed](https://www.formlaboratories.com/learn/igf-1-lr3/how-igf-1-lr3-works) - How IGF-1 LR3 works, in plain English: it uses the same receptor as IGF-I, but carrier proteins grip it much less. What the 1992 cell experiments and later animal studies measured, and what is not known.
- [IGF-1 LR3 side effects: what the records and studies document](https://www.formlaboratories.com/learn/igf-1-lr3/igf-1-lr3-side-effects) - What is documented about the safety of IGF-1 LR3, in plain English: no human trial exists, what the approved IGF-1 medicine label warns about, what a 2026 review says about low blood sugar and cancer concern, and a product-identity case report.
- [IGF-1 LR3 study findings: what cell, animal and human research shows](https://www.formlaboratories.com/learn/igf-1-lr3/igf-1-lr3-study-findings) - What published research found about IGF-1 LR3, in plain English: the 1992 cell work, rat, guinea pig, sheep and mouse studies, and why no human trial result was found to report. Each result is tied to its species and setting.
- [Is IGF-1 LR3 legal in Australia? Poisons Standard, TGA and WADA records](https://www.formlaboratories.com/learn/igf-1-lr3/is-igf-1-lr3-legal-in-australia) - What the Poisons Standard of October 2026, the TGA and the WADA 2026 Prohibited List say about IGF-1 LR3, in plain English, with the date each record was checked. Records only; this is not legal advice.
- [What is IGF-1 LR3? The lab-made IGF-I analogue explained from the research](https://www.formlaboratories.com/learn/igf-1-lr3/what-is-igf-1-lr3) - What IGF-1 LR3 is, in plain English: a lab-made copy of the hormone IGF-I with one building block swapped and an extra piece at the front, how it was first made, and where the human evidence stops.

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