Does IGF-1 LR3 (long R3 insulin-like growth factor-1) work?

Read Off Label rates the evidence for IGF-1 LR3 (long R3 insulin-like growth factor-1) as Weak and the benefit magnitude as med, producing an overall grade of D (2.9/10). Used in cell culture research, diverted for performance use.

Is IGF-1 LR3 (long R3 insulin-like growth factor-1) safe?

IGF-1 LR3 (long R3 insulin-like growth factor-1) has a high risk profile in published human data. Legal status: Research chem (not approved); banned sport. This is not medical advice — see the disclaimer.

Rankings / Muscle & Strength

IGF-1 LR3 (long R3 insulin-like growth factor-1)

Muscle & Strength · Modified IGF-1 analog

Tier D

Reviewed by Read Off Label · Last reviewed Jun 8, 2026 · How we grade

igf-1banned

2.9 / 10

Tier D

Ev 3 Bn 5 Sf 2

Bottom line

Read Off Label grades IGF-1 LR3 (long R3 insulin-like growth factor-1) as D (2.9/10) based on weak evidence, med benefit magnitude, and a high-risk safety profile.

Used in cell culture research, diverted for performance use.

Typical use: Typical illicit: 20-50 mcg/day subQ — Research chem (not approved); banned sport.

What this is

Used in cell culture research, diverted for performance use. Hypoglycemia is acute and potentially severe. Chronic IGF-1 signaling activation theoretically pro-oncogenic — longevity circles argue for LOWER IGF-1 for lifespan. Counterfeits and underdosed products rampant.

Mechanism

Modified IGF-1 with Arg3 substitution and N-terminal 13-aa extension; drastically reduced IGFBP binding — longer plasma half-life and higher bioavailability than native IGF-1

Dose & route

Typical illicit: 20-50 mcg/day subQ

Citations

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Common questions

Does IGF-1 LR3 (long R3 insulin-like growth factor-1) work?: Read Off Label rates the evidence for IGF-1 LR3 (long R3 insulin-like growth factor-1) as Weak and the benefit magnitude as med, producing an overall grade of D (2.9/10). Used in cell culture research, diverted for performance use.
Is IGF-1 LR3 (long R3 insulin-like growth factor-1) safe?: IGF-1 LR3 (long R3 insulin-like growth factor-1) has a high risk profile in published human data. Legal status: Research chem (not approved); banned sport. This is not medical advice — see the disclaimer.
What is the typical dose for IGF-1 LR3 (long R3 insulin-like growth factor-1)?: Typical illicit: 20-50 mcg/day subQ
How does IGF-1 LR3 (long R3 insulin-like growth factor-1) work?: Modified IGF-1 with Arg3 substitution and N-terminal 13-aa extension; drastically reduced IGFBP binding — longer plasma half-life and higher bioavailability than native IGF-1

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.