IGF1-LR3

IGF1-LR3 1 mg is Prime Time Bio Labs' single-milligram preparation of Long R3 IGF-1, sold as one single-use, lyophilized vial per order. "LR3" is shorthand for two things at once: the "Long" N-terminal extension and the "R3" arginine substitution that together define this analog's structure — a naming convention you'll see used interchangeably with "Long R3 IGF-1," "LR3-IGF-1," and "IGF-1 LR3" across the scientific and supplier literature. Each vial ships sealed and light-protected, with a lot-specific label so the physical unit in hand can be tied back to its Certificate of Analysis (COA) and batch record. That traceability matters more for a molecule like this than it does for a simple small-molecule reagent: IGF-1 LR3 is a recombinant polypeptide, and polypeptides are considerably more sensitive to handling, freeze-thaw cycling, and storage conditions than most lab compounds. A lot number that maps cleanly to a specific COA is what lets a researcher confirm that the vial on the bench actually matches the documented specifications, rather than trusting a generic product description that could apply to any batch ever produced. The "1 mg" in the product name refers to the total peptide content of the vial as shipped, not a working concentration — reconstitution volume and resulting concentration are left to the researcher's protocol and are covered in general terms in the Quality & Purity and FAQ sections below, without prescribing a specific use case. This is a meaningful distinction from home-use consumer products, where quantity and dose are often presented as interchangeable; in a research setting, they are not, and Prime Time Bio Labs' packaging and labeling are built around that difference. Because IGF1-LR3 is one entry in a broader category of research peptides and growth-factor analogs, it is worth being precise about what it is not. It is not native human IGF-1, and it is not interchangeable with the seventy-residue endogenous hormone that circulates in human and animal physiology. It is also not IGF-2 LR3 or any other IGF-family variant — a distinction that matters because supplier catalogs and search results for "IGF LR3" frequently blend several related-sounding entities together. The product identity for this listing is specifically Long R3 IGF-1, an 83-residue synthetic analog, and every specification, testing claim, and research reference on this page is scoped to that molecule. Physical presentation is straightforward: a lyophilized (freeze-dried) powder in a sealed glass vial, shipped and stored in a way designed to preserve peptide integrity prior to any reconstitution a research protocol might call for. Prime Time Bio Labs distributes this item, like the rest of its catalog, strictly for laboratory and in-vitro research use by qualified professionals — a point covered in full under Compliance Notice below.

Long R3 IGF-1 exists because of a specific, well-documented engineering problem in IGF-1 research: native IGF-1 binds tightly to a family of IGF-binding proteins (IGFBPs) circulating in serum, which sequester the hormone and shorten its effective window of biological activity in an experimental system. Researchers working with native IGF-1 in cell-based and animal models have historically had to account for this IGFBP interference when interpreting results. IGF-1 LR3 was developed as a way to reduce that interference at the molecular level, rather than working around it experimentally. The modification is built from two changes layered onto the native IGF-1 backbone. First, the glutamic acid residue at position 3 of the native sequence is replaced with arginine — the "R3" of the name. Second, a thirteen-residue extension is added to the N-terminus of the molecule — the "Long" of the name. Native human IGF-1 is a 70-residue polypeptide; adding the 13-residue extension to the modified 70-residue backbone brings the total to 83 residues, which is the length consistently reported for IGF-1 LR3 across supplier documentation and the peer-reviewed and reference literature. Structurally, these two changes are reported to reduce the molecule's affinity for IGFBPs substantially relative to native IGF-1, while largely preserving its ability to bind and activate the IGF-1 receptor (IGF-1R). That combination — lower IGFBP sequestration, retained receptor engagement — is the mechanistic basis for the extended bioactivity researchers have reported when using LR3 analogs in place of native IGF-1 in cell culture and animal-model work. Multiple sources describe a meaningfully extended circulating half-life for IGF-1 LR3 relative to native IGF-1 in these experimental contexts, though reported figures vary between sources and study designs, and Prime Time Bio Labs does not assert a specific half-life value as a product specification. At the receptor level, IGF-1R activation triggers two downstream signaling cascades that show up repeatedly in the IGF-1 literature: the PI3K/Akt/mTOR pathway, associated with cell survival, protein synthesis, and metabolic signaling, and the MAPK/ERK pathway, associated with cell proliferation and differentiation. Because reduced IGFBP binding leaves more of the administered analog available to engage IGF-1R in an experimental system, IGF-1 LR3 has been used as a research tool specifically where investigators want to probe these pathways with less confounding from binding-protein sequestration — for example, in cell-proliferation assays, myogenic differentiation models, and other in-vitro systems studying growth-factor signaling. It is worth being precise here about what is and isn't established. A meaningful share of the foundational work on IGFBP affinity, receptor binding, and comparative potency for LR3-type IGF-1 analogs comes from biochemical, cell-culture, and animal-model research — not from human clinical trials. Much of the deeper mechanistic literature on IGF-1 signaling more broadly was generated using native IGF-1, and while the receptor-binding chemistry is shared, that native-IGF-1 evidence base does not automatically transfer to every claim made about the LR3 analog specifically. Where this page describes receptor and pathway biology, it is describing the general IGF-1/IGF-1R signaling system as documented in the scientific literature, contextualized for why LR3-type modifications are relevant to that system — not asserting that every downstream effect has been independently confirmed for IGF-1 LR3 in every experimental model. Any application of this product is a matter for the researcher's own protocol and institutional oversight, in a laboratory or in-vitro setting only.

Every lot of IGF1-LR3 1 mg is third-party tested for purity, identity, and sterility before it ships, and the Certificate of Analysis (COA) tied to your specific lot is available for download from your account. That COA — not a generic spec sheet shared across every batch ever produced — is the actual documentation of what's in your vial. For this listing, the current COA on file (Batch PTB-IGF1LR3-1MG-0925) documents a purity of 99%, analyzed 8/27/2026. As with any peptide product, purity by third-party testing is a statement about analytical composition, not a statement about biological outcome: a high-purity result confirms that the material matches its intended chemical identity and is largely free of contaminating byproducts, but it does not establish potency in any particular assay, nor does it substitute for a researcher's own characterization within their specific experimental system. Identity and purity testing is likewise distinct from sterility testing, and sterility testing is distinct from any claim about suitability for a given research application — each is a separate line of evidence, and each is documented separately on the COA rather than folded into a single generic "quality" claim. Because IGF1-LR3 is a lyophilized recombinant polypeptide rather than a stable small molecule, storage conditions materially affect whether the material a researcher receives still matches its COA by the time it's used. Prime Time Bio Labs specifies freezer storage at -20°C, protected from light, for the unreconstituted lyophilized vial, with refrigerated storage at 2–8°C after reconstitution and use within the window noted on the COA. These are storage and handling specifications for maintaining product integrity — not dosing or administration instructions — and they exist because peptide degradation is cumulative and largely irreversible once it begins. A COA is also a useful tool for cross-checking supplier claims generally. Because "IGF-1 LR3" as a search term spans a wide range of suppliers with inconsistent documentation practices, a batch-specific, downloadable COA that actually matches the lot number physically printed on the vial is a meaningfully stronger form of quality evidence than a generic ">99% purity" badge with no underlying analytical record. Researchers evaluating any IGF-1 LR3 source — Prime Time Bio Labs or otherwise — are better served checking whether the COA on offer is lot-matched and third-party generated, rather than taking a purity percentage at face value.

IGF1-LR3 1 mg is distributed exclusively for qualified research purposes. It carries no FDA approval, is not a drug, dietary supplement, or cosmetic, and is not intended for human or animal consumption, diagnostic use, or therapeutic use of any kind. It must be handled only by trained laboratory personnel operating within an appropriate research or institutional setting. This restriction is not a formality. IGF-1 LR3 has not been evaluated by the FDA or any comparable regulatory body for safety or efficacy in humans or animals, and none of the scientific or mechanistic information on this page — including material describing IGF-1 receptor biology, IGFBP interactions, or cell-signaling pathways — should be read as guidance for human or veterinary use, dosing, or administration. That information is provided to give qualified researchers accurate scientific context for the product they are ordering, in the same way a reagent datasheet would; it is not usage instruction for any purpose outside a laboratory or in-vitro research setting. By ordering IGF1-LR3, the purchaser represents that they are acquiring the product for legitimate laboratory or in-vitro research use, that they are qualified to handle a research-grade recombinant polypeptide safely, and that they will not use, resell, or represent this product for human consumption, veterinary use, or any diagnostic or therapeutic purpose. Full terms are available in Prime Time Bio Labs' Terms & Conditions and Medical Disclaimer.