IGF-1 LR3 Peptide
Its main job worldwide is keeping cells alive in laboratory flasks. That is not a slight, it is a large and legitimate industry, and it is what this molecule was built for.
Choose your pack
For research use only. Not for human or veterinary use.
What IGF-1 LR3 Peptide is
The plain-language version, first.
Eighty-three residues, engineered twice over, for use in a flask.
IGF-1 LR3 is Long R3 insulin-like growth factor 1, an 83-amino-acid analogue of the native 70-residue hormone, carrying a 13-residue extension on the N terminus and an arginine substituted for glutamate at position 3. Both modifications reduce capture by the IGF binding proteins rather than improve receptor binding, and IGF-1 and its analogues are listed under section S2.3 of the WADA Prohibited List, banned in and out of competition.
Most things on this shelf were built hoping to become a medicine and did not get there.
This one was built to do a job it does extremely well, and that job is in a laboratory.
Long R3 IGF-1. Eighty-three residues. Its primary commercial market worldwide is cell culture media.
The engineering is two changes stacked. An arginine substituted at position 3, and a thirteen-residue extension added to the N-terminus.
Both changes are aimed at the same problem, which is that IGF binding proteins grab ordinary IGF-1 and hold it.
A molecule optimised for a flask. Which is a real industry, a large one, and not a euphemism for anything.
What is IGF-1 LR3?
Mechanism studied, not outcome promised.
The arginine at position 3 disrupts binding protein interaction. The analogue circulates free because nothing is holding it, not because it binds the receptor better.
In cell systems containing no binding proteins, the original characterisation found Long R3 IGF-1 less potent than native IGF-1 at the receptor.
Two modifications, both aimed at the same carrier-protein problem.
Picture a room where every time you hand somebody a tool, three other people grab it first.
You could hand out more tools. Or you could redesign the tool so it is harder to grab.
Both modifications here are the second strategy, applied twice.
The arginine at position 3 disrupts binding-protein interaction directly. The N-terminal extension makes the molecule a worse fit for the same proteins from a different angle.
Stack them and you get something that stays free far longer than native IGF-1, which in a culture flask is exactly what you want, because it means predictable exposure.
Here's the honest part. Predictable in a flask and predictable in a person are not the same claim.
A flask does not have a liver, a feedback loop, or thirty years of downstream consequences. Optimising away a control system is useful in the first setting and is a genuinely open question in the second.
The research so far for IGF-1 LR3 Peptide
Where the evidence is thin, we say so.
Bioprocessing. Long R3 IGF-1 is a standard cell culture supplement for mammalian lines, particularly CHO cells used to manufacture biologics, where serum-free media contain no binding proteins and stability is the valued property.
Humans. No registered clinical trials, no published pharmacokinetics, no efficacy or safety data in people. The human-adjacent literature concerns mecasermin, the native hormone, which is a different molecule.
More than 95 percent of circulating IGF-1 is bound to a family of six binding proteins, which act as a buffer, a reservoir and a delivery system rather than an obstacle. Free IGF-1 has a half-life of minutes; in the ternary complex with IGFBP-3 and the acid-labile subunit it lasts many hours. Long R3 is engineered specifically to escape that layer.
Enormous industrial use. Almost no human use.
There is a lot of literature here and you have to read the setting carefully.
Industrial and laboratory use is extensive. Biopharmaceutical manufacturing uses this molecule at scale, for good reasons, with well understood behaviour.
Human clinical work is a different and much smaller story.
No controlled trial in healthy adults for the reasons people search for it. Nothing approved for those uses anywhere.
Also prohibited in sport, which given the pattern of interest is not surprising.
Read the methods section before you read the abstract. A paper about this molecule is usually a paper about cells, and the distinction gets lost the moment it reaches a forum.
IGF-1 LR3 vial sizes and current stock are just below.
IGF-1 LR3 Peptide specs
The chemistry, exactly as released.
Who studies IGF-1 LR3 Peptide
Who tends to order this one, and why.
A research compound does not have one audience. It has a handful of rooms where the same question keeps coming up, and the question is a different question in each of them.
Bioprocessing and cell culture
The dominant global use. Serum-free media for CHO and other mammalian lines, where the analogue stability rather than its potency is the point.
Endocrinology
The IGF binding protein system, the ternary complex with the acid-labile subunit, and how a growth signal is buffered and delivered.
Growth factor pharmacology
Mecasermin, the native recombinant hormone, is approved for severe primary IGF-1 deficiency and is where the human clinical literature sits.
Anti-doping laboratories
Section S2.1 of the WADA 2026 list covers insulin-like growth factor 1 and its analogues, prohibited at all times and non-specified.
Sold for laboratory research only. This is not guidance for personal use, and nothing here is a recommendation.
IGF-1 LR3 Peptide backstory
How it got here.
IGF-1 was characterised as the mediator through which growth hormone produces many of its effects, which is why the growth hormone axis and the IGF axis are usually discussed together. The binding protein system was recognised early as central rather than incidental.
Six proteins, tissue-specific expression, and a ternary complex with the acid-labile subunit that keeps a large circulating reservoir stable. Understanding it was a substantial piece of endocrinology.
Long R3 was engineered against that system, in the early 1990s, primarily as a research and biotechnology tool. The goal was a form of IGF-1 that stayed active in culture conditions where native IGF-1 was rapidly bound or degraded.
It succeeded at that, which is why it became a standard bioprocessing reagent. Its use outside that context came later and without a development programme behind it.
- 1
The messenger for growth hormone
IGF-1 was characterised as the mediator through which growth hormone produces many of its effects, which is why the two axes are always discussed together.
- 2
A control system, recognised early
Six binding proteins with tissue-specific expression and a ternary complex that keeps a stable circulating reservoir. Understanding it was substantial endocrinology.
- 3
Engineered for the bioreactor
Long R3 was built in the early 1990s as a research and biotechnology tool, to stay active in culture conditions where native IGF-1 is rapidly bound or degraded.
Buying IGF-1 LR3 Peptide in Canada
What ships, how fast, and the paperwork.
The hard part of buying research material is almost never the compound. It is the logistics. What leaves the building, how fast it moves, and what is in the box beside the vial. Here is ours, plainly.
Most of the world supply feeds bioreactors
Long R3 IGF-1 principal commercial application globally is as a cell culture supplement in biologics manufacturing. That is a legitimate industrial market and it is worth knowing it is the main one.
Same day out of British Columbia
Our building, our cold packs, our people, and nothing sitting in a customs queue while you refresh a tracking page.
Covered by the WADA list
Section S2.1 covers insulin-like growth factor 1 and its analogues, which includes this one. Prohibited at all times, in and out of competition, and non-specified.
Stuff people ask about IGF-1 LR3 Peptide
If your question is not here, email us. Real human answers.
In a whole organism it produces more receptor activation, but not because it binds the receptor better. In cell systems that contain no binding proteins, the original characterisation work found Long R3 IGF-1 to be less potent than native IGF-1. Its entire advantage comes from evading the IGF binding proteins that normally sequester more than 95 percent of circulating IGF-1.
The arginine substituted for glutamate at position 3 disrupts binding to the IGF binding proteins, so the analogue is not captured. The 13 residue N-terminal extension further alters the molecule behaviour and contributes to its stability. Neither modification is aimed at improving receptor affinity.
No. There are no registered clinical trials, no published human pharmacokinetics, and no efficacy or safety data in people for this analogue. The human clinical literature in this area concerns mecasermin, recombinant native IGF-1, which is an approved drug for severe primary IGF-1 deficiency and a different molecule.
Because that is what it was engineered for and it works well at it. Serum-free culture media contain no IGF binding proteins, so there is nothing for the analogue to escape, but it is more stable than native IGF-1 under culture conditions and supports growth and productivity in mammalian cell lines. It is a standard supplement in biologics manufacturing, particularly for Chinese hamster ovary cells.
They are the control layer on a growth signal. Six proteins with tissue-specific expression sequester the vast majority of circulating IGF-1, extending its half-life from minutes to many hours in the ternary complex with IGFBP-3 and the acid-labile subunit, and regulating how much free hormone reaches tissue. Describing them as obstacles inverts what they do.
Yes. Section S2.1 of the WADA 2026 Prohibited List covers insulin-like growth factor 1 and its analogues, which includes Long R3 IGF-1. Prohibited at all times, in and out of competition, and classed as non-specified, which carries a heavier default sanction.
Good pairing options with IGF-1 LR3 Peptide
What researchers stack alongside it.
Pairing is where research gets ahead of itself. These are the compounds researchers put in the same order as IGF-1 LR3 Peptide, which is a statement about ordering habits, not about evidence. Two things in one cart have not been studied together unless somebody studied them together.
Not a molecule. FSH and LH activity extracted from postmenopausal urine and standardised in international units. Still marketed in Canada in 2026, which makes it the rare extract with live approvals.
The unprocessed precursor, all 344 residues with the signal peptide still attached. The protein your body actually secretes is a different animal: 315 residues and 36 cysteines folded just so.
Order IGF-1 LR3 Peptide right now
One last look before you decide.
Freeze-dried, COA on the page, ships cold
If you are researching IGF-1 LR3 Peptide and you want a source you do not have to second-guess, start with the paperwork on this page. For research use only.
Not for human consumption. Not approved by Health Canada or any other regulatory body.
Page last updated August 19, 2026
People also search for IGF-1 LR3 Peptide
Other names for the same compound.