musclehealing

IGF-1 LR3

Also known as Long R3 IGF-1, Insulin-like growth factor 1 LR3

A long-acting IGF-1 analog used for muscle growth and recovery.

Medical status: Not approved as a medicine; sold as a research chemical.

Also commonly used for (off-label)

Muscle growth and repair during a lean-mass block
Recovery from tendon and soft-tissue injury
Nutrient partitioning around training

Off-label and research uses are what people report, not approved indications. Talk to a clinician before using any of them.

How it's taken (route)

Subcutaneous injection
a small shot into the fat just under the skin (belly, thigh, or love handle)

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Documented dose: 33–100 mcg
Typical frequency: Once daily, within 30 minutes after training
Cycle: 8 weeks on, 6 off
Half-life: About 20-30 hours
Common vial sizes: 1 mg
Regulatory status: Research chemical — not approved for human use.

Dose on a U-100 syringe (33–100 mcg)

Vial	BAC water	Draw
1 mg	2.5 mL	8.3–25 units
1 mg	3 mL	9.9–30 units

On a U-100 syringe, 100 units = 1 mL, and the syringe holds 100 units total. Most people keep a single subcutaneous injection under about 50 units — bigger volumes are usually mixed stronger (less water) or split into two shots. Only mixes that fit in one syringe are shown. Always double-check with the reconstitution calculator.

What it does

IGF-1 LR3 is the downstream signal growth hormone actually works through, delivered directly. Your liver normally makes IGF-1 in response to GH; the "LR3" modifications stop carrier proteins mopping it up, so it stays active for many hours instead of minutes. What people look into it for: • Muscle fullness and growth during a lean-mass block • Faster recovery between hard training sessions • Tendon and soft-tissue repair after injury • Better nutrient uptake into trained muscle Because it is the signal itself rather than a releaser, it is potent — and that is also why blocks are kept short. Receptors down-regulate over time, and it shares enough structure with insulin to drop blood sugar in some people.

Mechanism

Binds the IGF-1 receptor and drives protein synthesis and cell growth. The LR3 modification stops it being bound up by carrier proteins, so it stays active far longer than natural IGF-1.

Storage — lyophilisedwhat's this?

Refrigerate the sealed vial.

Storage — reconstitutedwhat's this?

Refrigerate and use within about 4 weeks.

Reconstitution noteswhat's this?

IGF-1 LR3 needs 0.6% acetic acid, not plain bacteriostatic water — plain water degrades it. Mix a 1 mg vial with 2.5 mL (250 units) of 0.6% acetic acid. 8 units is about 33 mcg, 13 units about 50 mcg, 25 units about 100 mcg. Ramp up over the first weeks and always dose after training with carbs and protein.

Stacks well with

Popular combinations reported in the community and research literature — not a recommendation. Adding peptides multiplies side-effect risk; check with a clinician.

Commonly reported side effects

Low blood sugar
Hunger
Tingling or numbness in hands
Joint aches
Fatigue

Contraindications noted

Any active or prior cancer
Uncontrolled diabetes
Family history of hormone-sensitive tumours

Research notes

Blocks are usually kept to about 8 weeks or less because of receptor down-regulation, with a similar time off. Dose after training alongside carbohydrate and protein — never fasted or at bedtime — to blunt any drop in blood sugar. IGF-1 promotes growth of all cells, which is the core long-term risk and makes any personal or family cancer history a genuine clinician conversation rather than a formality.

Vendors carrying IGF-1 LR3

These research suppliers list this compound. Prices, vial sizes and testing vary — always check the current lot certificate before you buy.

Peptide Streak does not sell peptides and is not affiliated with these vendors. Some list metabolic compounds under coded product names.