§ 01 Overview
Overview
Long-acting analog of IGF-1 with reduced IGFBP binding, producing sustained anabolic signaling.
Research reagent status; no FDA trials. Used in bodybuilding communities.
§ 02 Mechanism
Mechanism of action
IGF-1 LR3 has an Arg3 substitution and an N-terminal Long peptide extension that reduces binding to IGF-binding proteins. This extends its half-life and free-fraction activity vs. native IGF-1.
- 01Anabolic / hypertrophy signaling
- 02Some reports of tissue repair support
- 03Potent compared to native IGF-1
§ 03 Dosing
Dosing protocol
Standard Protocol
- Vial
- 1 mg
- BAC Water
- 1 ml BAC water
- Dose Range
- 20 – 100 mcg per dose
- Starting Dose
- 20 mcg
- Route
- SubQ
- Timing
- Post-workout
- Frequency
- Daily during cycle
- Cycle
- Short cycles (2–4 weeks) due to desensitization and hypoglycemia risk
§ 04 Evidence
Evidence & research
Research reagent status; no FDA trials. Used in bodybuilding communities.
FDA Status
Not FDA-approved. WADA prohibited.
§ 06 News
In the news
4 articles from the last 12 months · updates hourly
Does IGF-1 Lower Blood Sugar? A Clear Look at the Evidence and Real-World Use - KMU
Does IGF-1 Lower Blood Sugar? A Clear Look at the Evidence and Real-World Use KMU
Best Peptides for Athletic Performance in 2026: Top Picks for Muscle Growth, Recovery & Endurance - Iredell Free News
Best Peptides for Athletic Performance in 2026: Top Picks for Muscle Growth, Recovery & Endurance Iredell Free News
Peptide Stacking Is Everywhere—But Should You Be Doing It? - Goop
Peptide Stacking Is Everywhere—But Should You Be Doing It? Goop
A pharmacological deep dive into the looksmaxxing world - felixonline.co.uk
A pharmacological deep dive into the looksmaxxing world felixonline.co.uk
§ 07 Sourcing
Sourcing & supply
Regulatory status
Restricted from compounding
Placed on the FDA's 503A Category 2 list and cannot be lawfully compounded in the US. No brand pharmacy alternative exists. US buyers encounter only research-use-only (RUO) channels, which the FDA's Intended Use Doctrine treats as unapproved drug sales.
Research-use-only · 3
Limitless Life Nootropics
'Only BBB-accredited peptide company' (since 2020). Claims three-lab third-party testing. Broad catalog.
Core Peptides
Broad catalog, widest payment range. Mid-credibility: Knoji 2.5/5 and one scam-impersonation report.
Ascension Peptides
Among newer RUO vendors with cleaner credibility signals. SafeCert Labs (CLIA-certified) testing, 4.8 Trustpilot. US-only.
Listings are informational, not endorsement. Verify credentials and flags against FDA and PCAB databases before purchasing. Full directory & how to verify →
§ 09 Safety
Safety & side effects
Side effects
- 01Hypoglycemia
- 02Injection site lump
- 03Potential tumor-promoting signaling
Contraindications
- 01Active or prior malignancy (IGF-1 signaling can be tumor-promoting)
- 02Retinopathy
§ 10 Questions
IGF-1 LR3 FAQ
- What is IGF-1 LR3?
- Long-acting analog of IGF-1 with reduced IGFBP binding, producing sustained anabolic signaling. IGF-1 LR3 has an Arg3 substitution and an N-terminal Long peptide extension that reduces binding to IGF-binding proteins. This extends its half-life and free-fraction activity vs. native IGF-1.
- What is IGF-1 LR3 used for?
- Reported uses include anabolic / hypertrophy signaling, some reports of tissue repair support, and potent compared to native igf-1. Evidence strength is rated Preclinical — see the evidence section for detail.
- How is IGF-1 LR3 dosed?
- Commonly referenced dosing is 20 – 100 mcg per dose, typically daily during cycle, administered SubQ. This is educational reference only; consult a licensed clinician before use.
- How do you reconstitute IGF-1 LR3?
- For IGF-1 LR3, vials commonly come in 1 mg and a common reconstitution is 1 ml BAC water. Use the reconstitution calculator to convert any vial size and water volume into exact insulin-syringe units.
- What are the side effects of IGF-1 LR3?
- Commonly reported side effects include hypoglycemia, injection site lump, and potential tumor-promoting signaling. This list is not exhaustive.
- Is IGF-1 LR3 legal?
- Placed on the FDA's 503A Category 2 list and cannot be lawfully compounded in the US. No brand pharmacy alternative exists. US buyers encounter only research-use-only (RUO) channels, which the FDA's Intended Use Doctrine treats as unapproved drug sales. FDA status: Not FDA-approved. WADA prohibited..