How most circulating IGF-1 is carried, and what that does to its half-life

Published 24 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
About three quarters of IGF-1 in the circulation is bound in a ternary complex of roughly 150 kDa: one IGF-1, one IGFBP-3 and one acid-labile subunit, a glycoprotein made in the liver under growth hormone control. Baxter and colleagues characterised the complex in the late 1980s. Free IGF-1 has a half-life of about ten minutes; in the ternary complex it is twelve to fifteen hours, and the complex cannot cross the capillary wall. IGF-1 LR3 binds IGFBP-3 poorly and therefore does not enter the complex, which is the point of the modification.

The three components

IGF-1 binds IGFBP-3 with high affinity to form a binary complex; the acid-labile subunit then binds the binary complex, not free IGFBP-3, to close the ternary complex. The subunit is named for falling apart at acid pH, which is how it was discovered. All three are induced by growth hormone, so the whole reservoir rises and falls together.

IGFBP-5 can substitute for IGFBP-3 in a minor ternary pool.

What the complex does

It is a reservoir. It keeps IGF-1 in the circulation, prevents it from acting on the insulin receptor at high concentration, and releases it by proteolysis of the binding protein where needed. Total serum IGF-1, the quantity measured clinically, is mostly complex-bound and reflects growth hormone status over days.

Free IGF-1 is a small fraction and much harder to measure.

Why this defines LR3

An analogue that cannot be bound is not stored or protected in this way. In cell culture that means more free ligand; in an animal it means a short half-life and no reservoir. Both are consequences of the same property, and both are reasons LR3 is a research reagent rather than a therapeutic.

IGF-1 LR3 is supplied by REVIVE LAB UAE for laboratory research use only, with identity and purity documented for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
IGF-1 LR3 Pack1 mgAED 650In stock

Delivery is AED 40 flat and free on orders over AED 700. Payment is cash on delivery anywhere in the UAE, or USDT (TRC20) in advance, which takes 5% off the order total.

Frequently asked

The three components?

IGF-1 binds IGFBP-3 with high affinity to form a binary complex; the acid-labile subunit then binds the binary complex, not free IGFBP-3, to close the ternary complex. The subunit is named for falling apart at acid pH, which is how it was discovered. All three are induced by growth hormone, so the whole reservoir rises and falls together.

Does REVIVE LAB UAE provide dosing guidance?

No. REVIVE LAB UAE supplies research materials and provides no dosing, administration or protocol guidance of any kind. Every product is sold for laboratory research use only and is not for human or veterinary consumption.

How fast is delivery in the UAE?

Stock is held in Dubai. An order confirmed before 4 PM Dubai time is dispatched the same working day, reaching Dubai and Abu Dhabi the same day and the remaining emirates within 24 hours. Delivery is AED 40 flat and free over AED 700.

IGF-1 LR3 Pack — in stock, dispatched from Dubai
HPLC-verified, lot certificate on every carton, 24-hour delivery nationwide. Browse the catalogue → All peptides UAE

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Supplied for laboratory research use only. Not for human or veterinary consumption. REVIVE LAB UAE provides no dosing, administration or protocol guidance.