Reviewed by the PeptideMind Team · Updated July 15, 2026

IGF-1 LR3 Dosage Guide, Benefits & Side Effects

IGF-1 LR3 drives muscle hypertrophy and nutrient partitioning with roughly triple the potency of native IGF-1. See mechanism and dosing.

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IGF-1 LR3 Dosage Guide for Muscle GrowthIGF-1 LR3 Dosage Calculator

IGF-1 LR3 is an anabolic peptide that promotes muscle growth and is injected under the skin or into the muscle.

Vial size

1 mg

Bacteriostatic water

1 mL

Dosing

20–50 mcg

Frequency

Daily

Cycle

3–4 weeks

Benefit

Muscle Growth

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Basic Dosage Calculator

Calculate peptide doses with our visual syringe guide.

Peptide per vial

Target research quantity

Bac water added

What is IGF-1 LR3?

IGF-1 LR3 is a lab-modified version of a natural growth factor (IGF-1) that's been altered to stay active in the body much longer, 20 to 30 hours instead of just minutes. This makes it significantly more potent for building muscle, preventing muscle breakdown, and supporting tissue repair. It's used mainly in research and by performance-focused communities interested in its strong anabolic (muscle-building) effects.

Growth

Research targets include growth hormone signaling, IGF-1 pathways, and tissue development.

Healing

Research targets include tissue repair, wound healing, and recovery from injury.

Growth

igf

Healing

Is IGF-1 LR3 FDA approved?

IGF-1 LR3 is not an FDA-approved drug. It is intended for research purposes only and is not approved for human consumption, diagnostic, or therapeutic use.

Research Use Only

IGF-1 LR3 has not been evaluated by the FDA for safety or efficacy in humans.

No Clinical Oversight

Not manufactured under FDA-regulated quality or clinical standards.

Unregulated Sourcing

Purity, dosing, and sourcing are not verified through FDA testing or oversight.

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How Does IGF-1 LR3 Work?

It attaches to and activates the same receptor that the natural growth factor IGF-1 uses, switching on pathways that drive muscle cells to grow bigger and multiply. Because it's less likely to get soaked up by binding proteins in the blood, more of it stays active and available, making it noticeably more potent than the natural version.

Activates IGF-1 receptor

Binds and activates the same receptor the natural growth factor IGF-1 uses.

Drives muscle growth

Switches on pathways that make muscle cells grow bigger and multiply.

Stays active longer

Less likely to get soaked up by blood proteins, so more stays available.

How to reconstitute IGF-1 LR3

View guide

The materials you'll need and step-by-step instructions for safely mixing IGF-1 LR3 with bacteriostatic water.

Materials needed

Your IGF-1 LR3 vial (lyophilized)

Alcohol swabs

Bacteriostatic sterile water

3 mL syringes (Luer Lock tip)

25G or 27G needles (Luer Lock). Other gauges may also be acceptable.

Sharps container (optional)

Remove the caps

Remove the caps from both your IGF-1 LR3 vial and your bacteriostatic water vial.

Sanitize the rubber stoppers

Wipe down the rubber stoppers on both vials with alcohol swabs and let them dry for about 3 minutes.

Attach the needle

Take your 3 mL syringe and needle. Twist the needle's plastic hub into the Luer Lock tip on the syringe to secure it.

Draw the bac water

Pull back on the plunger to draw your desired volume of bacteriostatic water. If you overfill, just push the excess back in until you reach the right marker on the syringe.

How much bac water? IGF-1 LR3 typically comes in a 1 mg vial. We recommend 1 mL of bacteriostatic water, though anywhere between 1 mL and 3 mL is acceptable. For larger vials you can use up to 5 mL — more bac water makes microdosing easier, but insulin needles usually max out at 1 mL per injection. That means a lot of bac water might force you into multiple injections to hit your target dose. Unless you're microdosing, 2 mL per vial is a solid rule of thumb.

Insert the needle into the IGF-1 LR3 vial

With the bac water in your syringe, insert the needle into the IGF-1 LR3 vial at a slight angle to avoid pressure buildup.

Use a thin needle: Stick to 25G or higher to avoid damaging the rubber stopper. Higher gauge means a thinner needle.

Release the water gently

Let the water run gently down the side of the vial. Don't inject it forcefully.

Heads up: Sometimes the plunger pushes itself in as soon as the needle enters the vial. Hold the plunger back so you have full control over how fast the bac water enters.

Swirl to dissolve

Avoid shaking. Gently swirl, flip, and roll the vial to dissolve the powder.

Be patient: This usually takes 2 to 5 minutes of consistent swirling, mixing in a circular motion, and gently flipping the vial up and down. The water needs to run through the powder many times to fully dissolve it. Don't shake or get aggressive with it.

Check for full dissolution

The solution should be clear with no visible particles. If it's cloudy or clumpy, wait a minute and repeat the swirling step.

Cap, dispose, and store

Once you're done, cap the needle and dispose of it (ideally in a sharps container). Store the reconstituted IGF-1 LR3 vial in the fridge whenever it's not in use. It will stay good for approximately 30 days.

How to Store IGF-1 LR3

Keep the dry powder in the fridge for up to a month, or frozen for up to a year. Once mixed with liquid, refrigerate and use within about a month, and don't freeze it once mixed.

Lyophilized Storage

Refrigerate at 2–8°C for up to 1 month, or freeze at -20°C for up to 12 months.

Reconstituted Storage

2–8°C, use within 28 days.

Handling Notes

Do not freeze the reconstituted solution.

A smartphone displaying a "Storage Guide" for peptides, indicating a safe storage temperature range of 2–8°C, with warnings to keep away from light, heat, and freezing. The background is light blue, and additional tips on protecting the peptides are visible below the temperature range.

What Are the Benefits of IGF-1 LR3?

What research says it may help with, and how it works in the body.

muscle growth

: Rats with cancer-related severe wasting (cachexia) kept 30% more muscle compared to rats given a placebo.
: Helps form new muscle fibers by prompting the muscle's repair cells (satellite cells) to mature into muscle tissue.
: In rat studies, it produced 15-20% gains in lean muscle mass within four weeks by activating the muscle's repair cells (satellite cells).

tissue repair

: Sped up wound healing in animal studies.
: Improves the repair of connective tissue, like tendons and ligaments.

metabolic

: Increases the breakdown of stored fat by acting through the same pathway as IGF-1.
: Steers nutrients in the body toward muscle tissue rather than other tissues.

What Are the Side Effects of IGF-1 LR3?

Who should avoid it, warning signs to watch for, and what to know before combining it with other compounds.

Who Should Avoid It

: NEVER approved for human use - research chemical only
: Cancer history or undiagnosed growths
: May cause organ hypertrophy (heart, intestines)
: WADA prohibited - causes failed drug tests

Stop Right Away If You Notice

: Severe or recurring hypoglycemia despite carbohydrate intake
: Unusual growths, lumps, or rapid mole changes
: Severe joint pain or carpal tunnel symptoms
: Persistent nausea, headaches, or vision changes
: Signs of organ enlargement
: Extreme fatigue or mental fog

Milder Signs to Watch For

Severe hypoglycemia risk - life-threatening low blood sugar lasting 20-30 hoursCancer proliferation concern - UK Biobank links elevated IGF-1 to multiple cancersBlack market quality varies - oxidized and degraded forms common

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How Long Should a IGF-1 LR3 Cycle Last?

This breaks down how long a typical IGF-1 LR3 cycle runs and what research suggests happens at each stage. Research shows that staying on a peptide continuously, without a break, may make it less effective over time.

That's why most research protocols build in a break between cycles, often called a washout period, to let the body reset before starting again.

Week 1-2: Increased muscle pump and fullness; possible hypoglycemia if carbs inadequate
Week 2-4: Enhanced recovery, strength gains, visible fullness, potential water retention
Week 4-6: Maximum effects; receptor desensitization approaching; joint stiffness common
Week 0-0: Pump loss over 1-2 weeks; strength/size gains may persist with training

Cheat Sheets Featuring IGF-1 LR3

See how IGF-1 LR3 fits into a broader research stack with these free downloadable cheat sheets. Each one includes reference dose ranges, dosing frequency, and half-life for every peptide it covers. For research purposes only.

View all

Growth Hormone Peptide Cheat Sheet

13 peptides

Healing & Recovery Peptide Cheat Sheet

18 peptides

Master Peptide Cheat Sheet

78 peptides

IGF-1 LR3 Research References

It is a preclinical compound

4Research references

IGF-1 LR3

IGF-1 LR3 is a preclinical compound

Rat Muscle Hypertrophy Study - Florini et al.

2.5mg/kg/day for 4 weeks showed 2.5x greater anabolic response compared to native IGF-1. Satellite cell activation and protein synthesis increased 50%.

1996

Fetal Sheep Metabolic Study

Acute infusion suppressed insulin secretion by 66%. Study halted early due to 4 animal deaths from hypoglycemia.

2000

Cancer Cachexia Rat Model

0.3mg/kg/day for 14 days showed 30% lean mass preservation during cachexia.

1998

UK Biobank Cancer Association

Elevated IGF-1 associated with multiple cancers including thyroid, colorectal, breast, prostate, melanoma.

2023

Frequently Asked Questions About IGF-1 LR3

Straight answers on reconstitution, dosing, and safety, everything you need to research with confidence. For research reference only.

IGF-1 LR3 ("Long Arg3-IGF-1") is a synthetic analog of human insulin-like growth factor 1. It contains an arginine substitution at position 3 and an extra 13-amino-acid extension at the N-terminus, giving it 83 amino acids versus the 70 of native IGF-1. This modification greatly reduces its binding affinity to IGF-binding proteins (IGFBPs), which in unmodified IGF-1 quickly deactivate and clear the hormone from circulation. Because IGF-1 LR3 escapes this binding, it stays biologically active in the bloodstream far longer and is reported to be roughly 2-3 times more potent than native IGF-1 in research settings.

IGF-1 LR3 has an extended half-life of approximately 20-30 hours, compared to native IGF-1's half-life of roughly 12-15 minutes (some sources cite up to 12-15 hours once bound to carrier proteins). This prolonged activity is the main reason it is used in research instead of unmodified IGF-1 — a single dose produces a much longer window of IGF-1 receptor stimulation, which is also why dosing frequency in research protocols is typically once daily rather than multiple times per day.

Commonly cited (non-clinical, anecdotal) protocols use 20-50 mcg per day, with some sources describing ranges up to 100 mcg/day depending on bodyweight and prior peptide experience, generally over cycles of 4-6 weeks followed by an equal or longer break. These figures come from bodybuilding/research-chemical communities and vendor guides rather than controlled clinical trials, and are not medical dosing recommendations. IGF-1 LR3 is sold strictly as a research chemical and is not approved for human administration, so no validated human dose exists.

The most frequently discussed acute risk is hypoglycemia (low blood sugar), because IGF-1 drives glucose into cells in a manner similar to insulin — this is why online guides stress never injecting in a fasted state and consuming carbohydrates afterward. Other effects reported in forums and vendor literature include water retention/edema, joint and connective tissue discomfort, headaches, fatigue, injection-site irritation, and concerns about compressive neuropathies (e.g., carpal-tunnel-type symptoms) and organ/tissue overgrowth with prolonged or high-dose use, given IGF-1's role as a growth-signaling hormone. These are anecdotal reports rather than data from controlled human trials, since IGF-1 LR3 has not been systematically studied for safety in humans.

As a lyophilized (freeze-dried) peptide, IGF-1 LR3 is generally reported to remain stable for 12-24 months when kept frozen (around -20°C), protected from light and moisture. Once reconstituted (commonly with bacteriostatic water, added slowly down the vial wall rather than directly onto the powder, then swirled gently — not shaken), the solution should be refrigerated at 2-8°C and is typically described as usable within about 2-4 weeks. Repeated freeze-thaw cycles and storage above refrigerator temperature are commonly cited as causes of peptide degradation and aggregation.

Both are derived from the IGF1 gene but act very differently. IGF-1 LR3 resists IGFBP binding and produces sustained, systemic IGF-1 receptor stimulation lasting many hours. MGF, by contrast, is a splice variant that the body naturally produces locally and transiently in mechanically stressed muscle tissue (e.g., after resistance exercise), with a much shorter window of activity focused on satellite cell activation near the site of muscle damage. In short: IGF-1 LR3 is discussed as a longer-acting, systemic signal, while MGF is discussed as a short-lived, localized one.

IGF-1 LR3 is not FDA-approved for human use and cannot legally be marketed or sold as a supplement or drug for human consumption. It is generally sold by research-chemical suppliers labeled 'for laboratory/research use only, not for human consumption,' which is the primary lawful sales channel. It is also explicitly banned in competitive sport — the World Anti-Doping Agency (WADA) prohibits IGF-1 and its analogs under its list of peptide hormones and growth factors. Any use in humans falls outside its intended research purpose and outside regulatory approval.

In bodybuilding and research-chemical forums, IGF-1 LR3 is frequently discussed alongside growth hormone secretagogues (e.g., GHRPs or GH releasing peptides) or anabolic compounds, based on the rationale that GH raises endogenous IGF-1 production while IGF-1 LR3 acts more directly and briefly at the receptor level. These combinations are discussed anecdotally in online communities and are not supported by controlled human studies establishing safety or effectiveness; stacking multiple substances that affect glucose regulation and growth signaling compounds the uncertainty and potential risk involved.

IGF-1 LR3 Dosage Guide, Benefits & Side Effects

IGF-1 LR3 Dosage Guide for Muscle GrowthIGF-1 LR3 Dosage Calculator

What is IGF-1 LR3?