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Animal data onlyNot FDA approved

IGF-1 LR3 side effects

Also known as: Long R3 IGF-I · LR3IGF-I · IGF LR3 · Long Arg3 IGF-1

Updated 20 sources

6 side effects reported for IGF-1 LR3: 2 from studies and labels, 4 from users and guides. 2 come with the ways people manage them.

IGF-1 LR3 overview

Side effects reported in studies and labels

Rates as each trial or label states them. A rate from one trial does not carry over to research-grade vials or other doses.

From trials and regulators2

Clinical studies and regulatory documents.

  • Growth-promoting (mitogenic) effects

    A theoretical concern from IGF-1 receptor biology. No human data exist either way

  • Label warnings for approved IGF-1 (mecasermin)

    Mecasermin's label lists severe hypoglycemia, raised pressure inside the skull, enlarged tonsils and malignant neoplasia. It is a different molecule, but the same receptor

    How people manage it

    • The label gives mecasermin shortly before or after a meal or snack.

Side effects users and guides report

What people post and what dosing guides list. These are reports, not measured rates.

From users and guides4

Community reports, competitor and vendor guides, media.

  • Low blood sugar (hypoglycemia)

    The main acute concern in guides, especially at 50 mcg and above. One guide states a 20 to 30% risk with no source. Approved IGF-1 has caused severe hypoglycemia

    How people manage it

    • Take it with food or fast carbs, never fasted.
    • Keep fast carbs on hand and monitor glucose.
    • Guides warn against combining it with insulin after training.
    • Labs guides use: fasting insulin, glucose and HbA1c.

  • Injection-site irritation

    Reported by guides

  • Brief stomach upset

    Reported by guides

  • Headache

    Reported by guides in weeks 1 to 2

How much is known

Animal data only

No peer-reviewed human studies. Evidence is cell work and rat studies on binding, potency and clearance. It was made as a cell-culture growth reagent; one black-market vial even held a His-tagged lab version. Every dose here is a community or guide convention.

Sources for these side effects

6 sources, each checked by date. Record updated Oct 23, 2026. Numbers are restated in our own words and labelled by where they came from.

Regulatory1

  1. Increlex labelDailyMed · checked Oct 23, 2026

Competitor guide4

  1. IGF-1 LR3PeptidesExplorer · checked Oct 23, 2026
  2. IGF-1 LR3 dosage protocolPeptidesExplorer · checked Oct 23, 2026
  3. IGF-1 LR3 dosage guideBodyHackGuide · checked Oct 23, 2026
  4. IGF-1 LR3 side effectsBodyHackGuide · checked Oct 23, 2026

Back to the full IGF-1 LR3 page for dosing, the vial chart and storage.