Muscle · Dosing reference

IGF-1 LR3 dosage

What the human evidence does and does not show, how long studies ran, and the arithmetic for working with vials.

Not approved — research use onlyCPreclinical researchNone established

Full research page Cycle-length evidence Compare Prefer Amiravo on Google

Regulatory status: Not approved — research use only
Human amounts: None established in humans
Route studied: —
Frequency: Not established
Half-life: Unknown in humans
Evidence grade: Grade C · Preclinical research
Vial sizes on the market: 0.1 mg · 1 mg
Other forms seen: —

What IGF-1 LR3 is

IGF-1 LR3 (Long R3 IGF-I) is a recombinant analogue of human insulin-like growth factor I with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension, designed as a laboratory reagent that binds poorly to IGF-binding proteins. It has been studied in cell culture and animals, but no published human administration study was identified. It is not approved for human use, is distinct from the FDA-approved drug mecasermin, and is prohibited in sport; this entry is for research reference only.

IGF-1 LR3 is an analogue of insulin-like growth factor I. Its design combines an Arg-for-Glu substitution at position 3 with a hydrophobic N-terminal extension ^1. Binding properties The original characterisation reported that N-terminal IGF-I analogues show increased biological potency because of changes in their interaction with IGF-binding proteins (IGFBPs), rather than higher receptor affinity; in a cell line… How it works →

Key evidence

Francis et al., J Mol Endocrinol · 1992 · Cells (L6 rat myoblasts, H35 hepatoma cells, chicken embryo fibroblasts)
Long [Arg3]-IGF-I was among the most potent analogues in cells secreting IGFBPs, but less potent than IGF-I in cells that do not secrete IGFBPs, indicating that reduced IGFBP binding drives the potency ^1. ¹
Tomas et al., J Endocrinol · 1997 · Animals (pigs; marmosets for other IGF-I variants)
IGF-I variants including LR3IGF-I were 2- to 3-fold more potent than IGF-I for glucose lowering and produced roughly 4- to 8-fold greater cumulative hypoglycaemia; only LR3IGF-I was more potent than IGF-I for lowering plasma amino acids ^2. ²
Kohler et al., Growth Horm IGF Res · 2010 · Analytical (seized black-market product)
The vial contained Long R3 IGF-I with a C-terminal His6 tag, consistent with a by-product of biochemical studies rather than a product made for injection ^3. ³

All studies on the research page

What the human evidence shows

No approved or established human dose

We searched PubMed and ClinicalTrials.gov and found no human studies that administered IGF-1 LR3. The research described on its page is from cells or animals, and animal amounts do not translate to people.

How long did human studies run?

No human studies; no duration of human use has been studied ^6.

Cycle-length evidence for IGF-1 LR3

Who was excluded from the studies

No human population has been studied; no label or contraindication list exists ^6,8.

IGF-1 LR3 draw calculator

Pick the vial strength and the water added, enter an amount, and see the concentration, the units to draw and how many draws the vial holds. Arithmetic only.

1 · Vial strength

sizes on the market

2 · Water added

3 · Amount per draw

4 · Syringe

Your mix

1 mg + 2 mL water = 0.5 mg/mL

10 units holds 0.05 mg (50 mcg)

Draw toEnter an amount in step 3

U-100 syringe · 100 units = 1 mL

Computed from your inputs. Not a dose or a recommendation.

Compare water volumes for this vialShow

More water = lower concentration = a larger, easier-to-measure draw. Tap a row to use it.

Water	mg/mL	Draw
0.5 mL	2	—
1 mL	1	—
1.5 mL	0.6667	—
2 mL	0.5	—
2.5 mL	0.4	—
3 mL	0.3333	—
5 mL	0.2	—

Supplies and handling

Lyophilized vial
Sealed vial with the freeze-dried cake. Check the label, lot and the certificate of analysis before opening.
Sterile diluent
The diluent named on the product documentation. Bacteriostatic water contains benzyl alcohol; sterile water does not.
Graduated syringes
Sized to the volume being measured. U-100 insulin syringes are graduated in units where 100 units = 1 mL.
Alcohol prep pads
For wiping vial stoppers before each puncture.
Nitrile gloves
Clean gloves for aseptic handling.
Sharps container
Puncture-resistant container for used needles.

Step-by-step reconstitution guide Storage and transport accessories

Storage

No approved-product storage instructions exist. Handling should follow the supplier's documentation; nothing here is a preparation or administration instruction.

Lyophilized (unmixed) vials: typically stored cold and dry, away from light, as the documentation directs. Many are stable longer frozen.
Reconstituted vials: typically refrigerated (about 2–8 °C), protected from light and not frozen.
Bacteriostatic water contains benzyl alcohol, which inhibits bacterial growth in multi-use vials; sterile water has no preservative.

Handling mistakes and troubleshooting

Added the wrong volume of diluent: The concentration changes, not the amount of compound in the vial. Recalculate with the volume actually added and relabel the vial.
Shook the vial and it foamed: Let it settle in the refrigerator. Foam is a sign of agitation; some peptides aggregate when shaken. Note it on the label.
The solution is cloudy or has particles: Do not use it. Cloudiness can indicate incomplete dissolution, contamination or degradation. Record the lot and contact the supplier with the certificate of analysis.
The powder cake looks melted or shrunken before reconstitution: This can indicate the vial was exposed to heat or moisture. Record the lot and condition on arrival.
Liquid sprayed back when the needle was removed: Pressure built up in the vial. Withdraw a small volume of air while adding diluent to keep pressure neutral.

Regulatory status

Status: Not approved for any human use. No registered clinical study was returned by a ClinicalTrials.gov search ^6, and IGF-1 LR3 does not appear in any category of FDA's May 14, 2026 503A bulk drug substances list ^8. It is a different molecule from mecasermin (INCRELEX), the FDA-approved recombinant human IGF-1 ^7. An anti-doping laboratory report describes Long R3 IGF-I as a product usually made for biochemical studies, found in a black-market injection vial ^3.
United States (FDA): Not approved. IGF-1 LR3 does not appear in any category of FDA's May 14, 2026 503A bulk drug substances list ^8. The FDA-approved IGF-1 product is mecasermin (INCRELEX, application 021839), which is a different molecule ^7.
Sport (WADA): Prohibited at all times. Section S2.3, Growth Factors and Growth Factor Modulators, names insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues ^9.

Status varies by country and changes over time. How we describe regulatory status.

IGF-1 LR3 compared with related compounds

Compound	Status	Evidence	Human amounts	Half-life
IGF-1 LR3	Not approved — research use only	C	None established	Unknown in humans
PEG-MGF	Not approved — research use only	—	None established	—
Follistatin 344	Not approved — research use only	—	None established	—

Frequently asked questions

What doses of IGF-1 LR3 have been studied in humans?

None that establish an amount. IGF-1 LR3 is not approved anywhere and we found no human studies that administered it. Amiravo does not publish community or vendor figures.

Is there an established IGF-1 LR3 cycle length?

No cycle length or break has been established. Human studies administered IGF-1 LR3 for the periods listed on this page; those are study durations, not a recommended course.

How much bacteriostatic water should be added to a IGF-1 LR3 vial?

There is no compound-specific volume. The diluent volume only sets the concentration: concentration = mass in the vial ÷ volume added (for example, 10 mg in 2 mL gives 5 mg/mL). The calculator on this page shows the arithmetic for any combination.

How many units is a given amount on an insulin syringe?

On a U-100 syringe, 100 units = 1 mL. Units for an amount = amount ÷ (concentration per unit). The calculator converts any amount you enter at the concentration you choose; a unit is a volume mark, not an amount of compound.

What is the half-life of IGF-1 LR3?

Unknown in humans

Is IGF-1 LR3 FDA-approved?

Not approved — research use only. Not approved for any human use. No registered clinical study was returned by a ClinicalTrials.gov search ^6, and IGF-1 LR3 does not appear in any category of FDA's May 14, 2026 503A bulk drug substances list ^8. It is a different molecule from mecasermin (INCRELEX), the FDA-approved recombinant human IGF-1 ^7. An anti-doping laboratory report describes Long R3 IGF-I as a product usually made for biochemical studies, found in a black-market injection vial ^3.

References

Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency J Mol Endocrinol. 1992
IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys J Endocrinol. 1997
Detection of His-tagged Long-R3-IGF-I in a black market product Growth Horm IGF Res. 2010
Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice J Alzheimers Dis. 2025
The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration Front Endocrinol (Lausanne). 2026
ClinicalTrials.gov API search for "long R3" IGF (no registered studies returned on 23 October 2026) ClinicalTrials.gov. 2026
Drugs@FDA application records for mecasermin (INCRELEX, application 021839, original approval 30 August 2005) openFDA / Drugs@FDA. 2026
Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act (categories 1, 2 and 3; updated May 14, 2026) FDA. 2026
International Standard: Prohibited List 2026 World Anti-Doping Agency. 2026

Last reviewed October 23, 2026 by the Amiravo editorial team. Editorial policy · Report an error