IGF-1 LR3: A Tracking Guide With a Hypoglycemia Warning

IGF-1 LR3 is a modified version of insulin-like growth factor 1 with an arginine substituted at position 3 and a 13-amino-acid extension at the N-terminus. Those changes drastically reduce binding to IGF binding proteins and extend the circulating half-life from minutes to around 20-30 hours. The result is a long-acting, systemic IGF-1 analog used in research and in bodybuilding self-experimenter circles.

The systemic action and long half-life are exactly what make it risky to underestimate.

What it does

• Binds the IGF-1 receptor with full potency
• Reduced IGFBP binding means more free, active peptide for longer
• Half-life around 20-30 hours (vs minutes for native IGF-1)
• Promotes protein synthesis, satellite cell activity, glucose uptake into muscle
• Suppresses GH and endogenous IGF-1 via negative feedback

Typical protocol shape

Commonly reported in self-experimenter circles:

• 20-50 mcg per day, subcutaneous
• Short cycles (4 weeks) followed by equivalent time off
• Some protocols inject post-workout; given the long half-life, timing is less critical than with DES

Doses higher than that are reported but the hypoglycemia and side-effect profile gets worse fast.

What to track daily

• Dose, time, site
• Hypoglycemia symptoms: shakiness, sweating, confusion, hunger
• Blood glucose if you have a meter, especially first 2-3 hours post-injection
• Sleep quality
• Energy, mood
• Joint or nerve symptoms (carpal-tunnel-like complaints reported)

What to track weekly

• Bodyweight
• Waist and limb measurements
• Strength on key lifts
• Photos in consistent conditions
• Subjective fullness/pump score

Bloodwork worth doing

• Baseline: fasting glucose, insulin, HbA1c, IGF-1, IGFBP-3, lipid panel, CMP
• Mid-cycle and post-cycle: same
• IGF-1 assays often do not distinguish endogenous from LR3, so the number is informational, not diagnostic
• HbA1c trend over multiple cycles is more useful than any single reading

Realistic expectations

• Weight gain, much of it water and glycogen, is common
• Strength changes within a 4-week cycle are modest
• Hypoglycemia risk is real and dose-dependent
• Long-term hypertrophy effects beyond what training plus food provide are unproven in healthy adults

Common mistakes

• Treating LR3 like insulin in terms of food timing (it lasts much longer)
• Skipping a glucose meter "because it's not insulin"
• Long continuous cycles with no IGF-1 axis recovery period
• Ignoring family cancer history when considering chronic IGF receptor stimulation

A tracking template

• Daily: dose, time, site, hypoglycemia symptoms, glucose readings, sleep
• Weekly: weight, measurements, strength, photos
• Pre/mid/post cycle: fasting glucose, insulin, HbA1c, IGF-1, IGFBP-3, CMP
• Long-term: HbA1c trend across cycles

Peptid AI's glucose-tagging and cycle comparison views are particularly useful here because the cross-cycle HbA1c trend is the thing most users ignore.

Safety notes

Hypoglycemia is the acute risk. Eat before injecting, keep fast-acting carbs nearby, and do not inject and drive. Theoretical cancer-promotion concerns with chronic IGF receptor stimulation are not zero. Anyone with a personal or family history of hormone-sensitive cancers, active retinopathy, or poorly controlled diabetes should not be self-experimenting here.

Peptid AI is an educational and self-tracking tool. Nothing in this post is medical advice. Doses mentioned reflect what is commonly reported in research literature — they are not recommendations. Always consult a qualified physician before starting, changing, or stopping any protocol.