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Decoding

IGF-1 LR3_

Also known as Long R3 IGF-1, LR3

A powerful muscle-builder that also drops blood sugar hard.

Muscle growthIGF-1 analogResearch onlyHigh-risk
InMuscle building
Common vial size1 mg
Dose0.02 up to 0.05 mg per day (start low, increase slowly)
FrequencyDaily, cycled
RouteUnder the skin or into muscle
StatusResearch only
MixYour choice, calculate it
CycledCommonly run in 4 week blocks

Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.

01

What is IGF-1 LR3?

Plain language first. The technical label stays, but it never stands alone.

Overview

IGF-1 LR3 is a long-acting version of insulin-like growth factor 1, the hormone that growth hormone works through to build tissue. In plain terms: it directly drives muscle cells to grow and repair and stays active for hours, but it also drops blood sugar hard.

What it's used for

A powerful muscle-builder that drives growth in muscle cells and speeds recovery, staying active for hours.

02

How does IGF-1 LR3 work?

What it does in the body, and where.

IGF-1 LR3 is a modified version of the hormone that growth hormone works through, engineered to stay active far longer than the natural form.

  1. 01
    It binds IGF-1 receptors on muscle cells
    Driving growth and repair directly, without going through growth hormone at all.
  2. 02
    The modification stops it being bound and stored
    Natural IGF-1 is mostly held inactive by binding proteins. LR3 evades them, which is what makes it potent and long-lasting.
  3. 03
    Blood sugar drops
    IGF-1 is structurally close to insulin and acts partly like it. Hypoglycaemia is a real and immediate risk, not a theoretical one.
  4. 04
    There is no human trial supporting its use for muscle
    Everything is extrapolated from what IGF-1 does physiologically.
Pathway
THE PEPTIDEIGF-1 LR3ACTS ONIGF-1 receptors on muscle cellsRESULTMuscle cells grow a…RESULTBlood sugar drops

A schematic of the compound's mechanism, not a diagnostic image.

03

What else is it used for?

Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.

  • Driving muscle growth directlyResearch only
  • Speeding recovery from trainingResearch only
04

How much, and do you cycle it?

The range, and whether you take breaks.

0.02 up to 0.05 mg per day (start low, increase slowly), daily, cycled. Commonly run in 4 week blocksCommunity practice

The block length comes from community practice. The stated concern is that holding IGF-1 high for long periods drives growth in tissue you did not intend, and it can drop blood sugar hard. No human study establishes a schedule or a safe duration.

Compare cycling across compounds →

05

How do I dose and price it?

Enter your vial and your dose. Pick a mix. We show the draw and the cost.

The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.

Your vial size (mg)
Printed on the vial.
What you paid per vial
$
Used for cost per dose only.
Your dose (mcg)
Commonly referenced range: 0.02 up to 0.05 mg per day (start low, increase slowly)Community practice

Choose your mix

your own mL
units · —
Enter your own volume

Measuring the water1 mL = one full 100-unit syringe.

Your draw

4 / 100 units
4 units is a very small line to read, so a small slip is a large error. A larger water volume above spreads the same dose across more units.
Full calculator with reorder date →Read a syringe →
06

How do you store it?

Before mixing, and after.

Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.

Unmixed lyophilized IGF-1 LR3 keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.

07

What are the side effects and cautions?

Known cautions and warnings for this compound.

22 July 2026Not approved for any use. The low-blood-sugar risk is the practical danger, and it is the reason combining it with insulin is described as dangerous.

Handling note

Mixing exception: reconstitute this one with a dilute acetic acid solution, not bacteriostatic water. Plain BAC water can degrade it, so follow the product's own mixing instructions.

Community notes: what actually helps

What actually helps, according to the people doing it

Nobody's running trials on this. What follows is the folk wisdom that keeps surfacing in Reddit, peptide forums, and the Discord groups, sorted from "probably real" to "someone swears by it." Keep in mind, NONE of this is doctor advice.

Change how you inject (this helps most people)

The tip that comes up most on r/peptides is to add more water. Mix your vial with 3 or 4mL of bac water instead of 1 to 2mL. Same dose, spread thinner, so your skin reacts less.

Small habits people swear by
  • Let it warm to room temperature. Cold stings more.
  • Let the alcohol dry fully before the needle goes in.
  • Inject slow, over five to ten seconds.
  • Move your spot around, at least an inch from last time.
  • For a hard lump, warm compress after. For a red itchy welt, ice.
Treat the itch

This is where Benadryl and Zyrtec come up constantly on the boards. Most people take one 30 to 60 minutes before the shot if they know they tend to react. Claritin works too. Some skip the pill and use Benadryl cream before, or hydrocortisone cream after. Quercetin gets mentioned a lot as the gentler, natural option.

One heads up you'll also see repeated: taking an allergy pill before every shot can hide a real allergy building underneath. That's why some people don't do it by default.

The deeper end

In the more advanced threads, people keep KPV around and inject it when a reaction flares, and say it clears fast. Others try low-dose naltrexone (LDN) as a longer-term fix, but that's real experimenter territory. And a common reminder on the forums: if your reactions are suddenly bad or started with a new vial, the peptide itself might be the problem, not you.

When to stop and get help

Redness that spreads past a couple inches, streaks, feels hot, oozes, or comes with a fever means a possible infection. See a doctor. Hives all over, a swollen face or throat, or trouble breathing is a real allergic reaction. Act on that right away.

Who should avoid it

Check these before anything else.
  • Any history of cancer, given the growth-promoting mechanism
  • Diabetes, or any use of insulin, because the blood-sugar drop can be dangerous
  • Pregnancy
  • Banned in drug-tested sport

Stop and get help

These are emergencies. Seek care.
  • Signs of very low blood sugar such as shaking, sweating, confusion, or fainting, which needs fast-acting sugar and urgent help
  • New lumps or masses
  • Severe headaches or vision changes
  • Signs of an allergic reaction such as face or throat swelling, hives, or trouble breathing

Common effects

Expected, and usually mild.
  • Low blood sugar, which is the main and most dangerous effect
  • Injection-site reactions
  • Joint pain
  • Water retention

Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.

08

Is IGF-1 LR3 approved?

And where the numbers on this page come from.
Research only

No. Not FDA-approved.

Not approved for any use. The low-blood-sugar risk is the practical danger, and it is the reason combining it with insulin is described as dangerous.

  • DoseFrom research and community reports. No regulator has reviewed this dose.
  • Vial sizeFrom what vendors typically list; not a recommendation.
  • Reviewed22 July 2026
09

What else is like IGF-1 LR3?

Others in Muscle building, side by side.

If you're weighing IGF-1 LR3, it's worth reading Bimagrumab, Ipamorelin + CJC-1295 blend, and IGF-1 DES in the same class.

YOU ARE HERE
LR383 residues
IGF-1 LR3

A powerful muscle-builder that also drops blood sugar hard.

Research only
Dose
0.02 up to 0.05 mg per day (start low, increase slowly)
How often
Daily, cycled
BIMA300 residues
Bimagrumab

An experimental shot that strips fat while adding muscle.

Investigational
Dose
10 up to 30 mg/kg per month (trial doses)
How often
Monthly
IPA+CJCBlend
Ipamorelin + CJC-1295 blend

The popular growth-hormone combo in one shot, for muscle, recovery, and sleep.

Research only
Dose
~100 mcg CJC + 200-300 mcg ipa
How often
Daily, often at night
DES67 residues
IGF-1 DES

A short-acting muscle-builder that works right where you inject it.

Research only
Dose
0.05 up to 0.15 mg per dose (start low, increase slowly)
How often
Around training
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10

What these words mean

Show glossary +
Titrate
Starting at a low dose and increasing it slowly over time so your body adjusts and side effects stay mild.
Subcutaneous
An injection just under the skin, into the fat layer, usually with a short, thin insulin needle.
Intramuscular (IM)
An injection into a muscle, using a longer needle.
Reconstitution
Mixing a powdered peptide with liquid (bacteriostatic water) so it can be drawn into a syringe.
Bacteriostatic water
Sterile water with a tiny amount of preservative, used to mix powdered peptides.
Concentration
How strong the mixed peptide is, in milligrams per milliliter (mg/mL). More water makes it weaker; less water makes it stronger.
Units (on the syringe)
The marks on an insulin syringe. 100 units equals 1 mL. They measure how much liquid you draw, not the dose in milligrams.
mcg and mg
Units of dose. 1 milligram (mg) equals 1,000 micrograms (mcg).
GLP-1
A natural gut hormone that lowers appetite and blood sugar. Drugs that copy it, like semaglutide, are used for weight loss.
Growth hormone secretagogue
A compound that nudges your body to release more of its own growth hormone, rather than injecting the hormone itself.
Half-life
How long a compound stays active in your body. A longer half-life means you inject less often.
Peptide vs small molecule
A peptide is a short chain of amino acids. A few items here (like MK-677 or methylene blue) are small molecules, not true peptides, but people use them the same way.
Research only
No approved dose or use in people. Sold for research and not reviewed by the FDA for safety or quality.
Investigational
Still being tested in clinical trials and not yet approved or legally sold for general use.
Banned in drug-tested sport
Prohibited by the World Anti-Doping Agency (WADA); using it can disqualify a competing athlete.

Last reviewed 22 July 2026