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Why women secrete more growth hormone than men for the same IGF-1, and what oral oestrogen does

Published 26 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
Women secrete growth hormone at higher amplitude and with higher baseline levels than men, yet have similar circulating IGF-1, because oestrogen reduces the liver response to the hormone — in part by inducing suppressors of cytokine signalling that dampen the JAK2-STAT5 pathway. Oral oestrogen, which reaches the liver at high concentration before dilution in the circulation, lowers IGF-1 substantially; transdermal oestrogen, which does not, has little effect. Leung and colleagues reviewed the mechanism in Endocrine Reviews in 2004. The effect bears on how deficiency is diagnosed and monitored in women and on the interpretation of IGF-1 in anyone taking oral oestrogen.

The physiology

Oestrogen acts on hepatocytes to increase expression of SOCS2 and related proteins, which bind the activated growth hormone receptor and JAK2 and limit STAT5 signalling. Less IGF-1 is made per unit of hormone. The hypothalamus compensates by secreting more hormone, so growth hormone is higher and IGF-1 is normal — a reset of the feedback loop. The same mechanism contributes to the higher growth hormone levels of puberty in girls.

The pulsatile pattern also differs: women show more irregular, higher-baseline secretion.

The first-pass effect

Swallowed oestrogen is absorbed into the portal vein and passes through the liver at concentrations far above those reaching other tissues. Hepatic IGF-1 production falls, and in women with growth hormone deficiency the amount of hormone needed to normalise IGF-1 is substantially higher on oral than on transdermal oestrogen. This is well documented in the adult deficiency literature.

It is one of the clearest examples of a route of administration changing an endocrine effect.

Why it is here

Because IGF-1 is the readout used throughout the growth hormone literature and sex and oestrogen status change what it means. This page states physiology; it describes no use of the pack.

Somatropin 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
HGH Somatropin Pack24 mg (72 IU)AED 850In 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 physiology?

Oestrogen acts on hepatocytes to increase expression of SOCS2 and related proteins, which bind the activated growth hormone receptor and JAK2 and limit STAT5 signalling. Less IGF-1 is made per unit of hormone. The hypothalamus compensates by secreting more hormone, so growth hormone is higher and IGF-1 is normal — a reset of the feedback loop. The same mechanism contributes to the higher growth hormone levels of puberty in girls.

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.

HGH Somatropin 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

→ HGH Somatropin Pack — 24 mg (72 IU) → JAK2 and STAT5 → The IGF-1 international standard

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