The one methionine in the IGF-1 sequence, and what its oxidation does

Published 24 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
IGF-1 has one methionine, at position 59 in the A domain, close to the receptor-binding surface. Oxidation to methionine sulfoxide adds sixteen daltons, is detectable by mass spectrometry and separable by reversed-phase chromatography, and has been reported to reduce receptor affinity several-fold. In IGF-1 LR3 the same residue sits at position 72 because of the extension. It is the principal chemical degradation product of the protein in solution and under light.

Where it is and why it matters

The A domain contributes to the receptor-binding face. A sulfoxide at 59 is more polar and bulkier than the thioether and perturbs that face, which is why the oxidised form is less active rather than merely different. Somatropin, by comparison, has three methionines and its oxidised forms are less affected in activity.

A single oxidation site makes the degradation easy to quantify.

How it arises and how it is seen

Dissolved oxygen, trace peroxide in excipients and light-generated radicals all oxidise methionine. The reaction is slow in the dry solid and faster in solution. Reversed-phase chromatography resolves the oxidised form as an earlier peak; intact mass shows the sixteen-dalton shift; peptide mapping places it at the residue.

Protect-from-light storage on the pack addresses one of the drivers.

On the certificate

Reported within related substances by the chromatographic method. A batch figure for oxidised form is part of describing the lot as released.

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

Where it is and why it matters?

The A domain contributes to the receptor-binding face. A sulfoxide at 59 is more polar and bulkier than the thioether and perturbs that face, which is why the oxidised form is less active rather than merely different. Somatropin, by comparison, has three methionines and its oxidised forms are less affected in activity.

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

Related reading

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