IGF-1 LR3 1 mg vial dosage

What IGF-1 LR3 is

Class:

Recombinant analogue of insulin-like growth factor 1 (IGF-1), 83 amino acids

Also called:

Long R3 IGF-1, Long-R3-IGF-1

Used for:

Originally engineered as a laboratory reagent - an IGF-1 variant with reduced binding to IGF-binding proteins, used to study IGF-1 signalling in cell culture. Sold to consumers as a research chemical for muscle growth, a use with no controlled human trial behind it.

Human evidence:

Animal / lab only. I could not locate a controlled human trial of IGF-1 LR3, for muscle gain, body composition or any other consumer use, in the source registry this site cites from. What is published is cell-culture and receptor-binding pharmacology using IGF-1 LR3 as a research reagent, plus animal studies: growth and nitrogen balance in steroid-treated, diabetic and normal growing rats, blood-glucose lowering in pigs, a 7-month intranasal study in a mouse Alzheimer's model, and a one-week infusion into growth-restricted fetal sheep that did not improve growth. None is a test of the molecule as something a person injects.

US status:

Research use only. Not FDA-approved for any indication in the US; no IGF-1 LR3, "Long R3 IGF-1" or equivalent product is listed on DailyMed (checked 2026-09-24). IGF-1 LR3 is a distinct molecule from mecasermin (brand name Increlex), the only FDA-approved recombinant human IGF-1 product - see the "Not mecasermin" section on the reader-facing page. Exogenous IGF-1 and its analogues, which IGF-1 LR3 is reported to be, fall under the World Anti-Doping Agency S2 category (peptide hormones, growth factors and related substances), prohibited at all times; a tested athlete should check the current WADA Prohibited List directly.

The full picture, with every study: IGF-1 LR3 guide.

How to mix a 1 mg IGF-1 LR3 vial

For this vial: 1.5 mL of bacteriostatic water makes 0.67 mg/mL, so 35 mcg is 5.5 units (0.05 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. ^[3][4]
2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. ^[3][4][5]
3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. ^[6]
4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. ^[3][4][6]
5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. ^[3]
6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. ^[6]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing IGF-1 LR3 vials

• Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. ^[7]
• Protect peptide vials from heat and light. ^[7][8]
• Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. ^[6][7]
• Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. ^[9][10]

More detail: peptide storage and shelf life.

Injecting safely

• Clean the injection site with an alcohol swab and let the skin dry completely before injecting. ^[11][12]
• Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. ^[11][12][13]
• Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. ^[11]
• Inject slowly, at roughly 10 seconds per mL. ^[11]
• Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. ^[6][11][12]

Hygiene and warning signs

• Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. ^[5][9][12]
• Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. ^[5][8][9]
• Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. ^[14][15]
• Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. ^[12]

Where to inject: subcutaneous injection sites.

How IGF-1 LR3 works

• IGF-1 LR3 (Long [Arg3]-IGF-I) is human IGF-1 with two changes: the glutamic acid at position 3 is swapped for arginine, and the first 11 amino acids of porcine growth hormone plus two linking residues are added to the front. It was described in 1992, made in E. coli as a laboratory reagent for studying IGF-1 action. ^[16]
• Its extra potency comes from binding poorly to IGF-binding proteins, which normally hold IGF-1 in reserve. In cell lines that release these proteins it was among the most potent forms tested, but in chicken embryo cells, which do not release them, it was less potent than native IGF-1. ^[16]
• IGF-1 LR3 binds the IGF-1 receptor about 3-fold less well than native IGF-1, yet in dexamethasone-treated rats it was about 2.5-fold more potent. The authors linked this to IGF-binding proteins blocking native IGF-1, but not the variant, from reaching tissues. ^[17]

What the IGF-1 LR3 research found

Human evidence: animal / lab only. Each result says what was studied.

• Animal studyIn rats made catabolic with dexamethasone, IGF-1 LR3 and des(1-3)IGF-1 given by mini-pump for 7 days were about 2.5-fold more potent than native IGF-1 at reversing weight loss and improving nitrogen retention. ^[17]
• Animal studyIn normal growing female rats treated for 14 days by mini-pump, 44 micrograms a day of IGF-1 LR3 matched the gains in body weight, nitrogen retention and feed efficiency produced by 278 micrograms a day of native IGF-1. ^[18]
• Animal studyIn diabetic rats, IGF-1 LR3 was 2.5-3 times more potent than native IGF-1 at restoring growth, but it did not reduce glucose loss in the urine, which insulin did. ^[19]
• Animal studyA null result: in growth-restricted fetal sheep, a one-week intravenous infusion of IGF-1 LR3 (7 treated, 7 controls) did not improve fetal growth, and circulating amino acids fell. ^[20]
• Animal studyIn a mouse model of Alzheimer's disease, 7 months of intranasal IGF-1 LR3 improved body composition and changed some amyloid plaque features but did not preserve memory or behaviour. ^[21]
• Animal studyAfter a single intramuscular injection in rats, unchanged IGF-1 LR3 disappeared from the blood rapidly after 4 hours, while des(1-3)IGF-1 stayed detectable for 24 hours. Black-market IGF-1 analogue products showed abundant oxidised, lower-quality peptide forms. ^[22]

IGF-1 LR3 side effects and risks

No human study of IGF-1 LR3 has been published, so there is no human safety data; the effects listed are from animal studies.

• Animal studyIn pigs, a single injection of IGF-1 LR3 lowered blood glucose 2-3 times more potently than native IGF-1, and the low-IGFBP-binding variants kept glucose down for much longer, with 4- to 8-fold more cumulative hypoglycaemia over 4 hours. ^[23]
• Animal studyIn dexamethasone-treated rats, native IGF-1 increased total gut weight by up to 60% over 7 days, and IGF-1 LR3 had the same kind of effect at several-fold greater potency. ^[24]

Other things to know

• Mecasermin, the only FDA-approved recombinant IGF-1 product, carries a warning that severe hypoglycaemia, including hypoglycaemic seizures, has been observed with treatment. IGF-1 LR3 is a different molecule with no human dosing trial behind it, but it acts on the same IGF-1 receptor pathway, and in pigs a single injection of IGF-1 LR3 lowered blood glucose 2-3 times more potently than native IGF-1 and for longer. That is an animal finding; no one has measured it in people.
• IGF-1 signalling drives cell growth and proliferation. No human trial has tested whether unsupervised, unmonitored IGF-1 LR3 dosing raises the risk of abnormal tissue growth; this is an unanswered question, not a documented risk, and should be treated as such.
• No long-term human safety data exist for IGF-1 LR3 itself. What is published is laboratory reagent pharmacology and animal studies, not repeated-dose studies in people.
• No established human half-life or dosing interval I could verify against a primary source. In rats given a single intramuscular injection, unchanged IGF-1 LR3 disappeared from the blood rapidly after about 4 hours; native IGF-1 was not measured for comparison. Sold as a research chemical labelled not for human use, with no independent verification of what a given vial actually contains.
• Reported to fall under IGF-1 and its analogues in the WADA S2 category, prohibited at all times in sport; a tested athlete should verify the current list directly.

Reported side effects and what the studies measured: IGF-1 LR3 side effects.

Where this vial size comes from

IGF-1 LR3 is sold as a 1 mg vial by the pages below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

• SwissChemsvendorLists it as: Total Compound Content: 1 mg per vial · checked 2026-09-28
• BioEdge Research LabsvendorLists it as: "Vial Size: 3 mL sterile vial"; "Fill: 1mg" · checked 2026-09-28

The doses come from the sourced common protocol on the IGF-1 LR3 dosing page, and every number on this page is arithmetic on those doses and this vial size.

Where to buy IGF-1 LR3 for research

Sold for research use only. Listed by Next Level Pharm and BioEdge Research Labs; compare them on my vendors page or see the listing on the IGF-1 LR3 page.

Questions

How much water do I add to a 1 mg IGF-1 LR3 vial?

There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1.5 mL the vial is 0.67 mg/mL and 35 mcg is 5.5 units (0.05 mL) on a U-100 insulin syringe. The units table gives 1.5, 3, 5 mL.

How many doses are in a 1 mg IGF-1 LR3 vial?

50 doses at 20 mcg, 28 doses at 35 mcg, 20 doses at 50 mcg.

How long does a 1 mg IGF-1 LR3 vial last?

At 35 mcg a dose and once daily, about 4 weeks. How long a mixed vial keeps is a separate limit; see storage below.

How many 1 mg vials do I need for a cycle?

1 vial at 20 mcg 7 times a week for 1.5 weeks; 3 vials at 50 mcg 7 times a week for 6 weeks.

What does 1 unit equal in a 1 mg IGF-1 LR3 vial?

6.67 mcg with 1.5 mL, 3.33 mcg with 3 mL, 2 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.