Two circulating forms of one hormone, why both are active, and why tesamorelin kept the longer

Published 26 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
Two forms of growth hormone-releasing hormone circulate: GHRH 1-44, with an amidated carboxyl terminus, and GHRH 1-40, a free acid ending at residue 40, produced by alternative processing of the same precursor. Rivier, Vale and colleagues isolated the 40-residue form from one tumour and Guillemin and colleagues the 44-residue form from another in 1982, and both were fully active in releasing growth hormone. Residues 30 to 44 are not needed for receptor activation, so the two forms are pharmacologically similar; the longer form is somewhat more stable. Tesamorelin was built on the 44-residue amide, keeping the natural carboxyl terminus and the stability it confers.

The two forms

Both come from the same 108-residue precursor. Cleavage after residue 44 with amidation gives the major form; cleavage at an internal basic site gives the 40-residue acid. Their relative proportions vary by tissue. Both bind the receptor with similar affinity and release growth hormone with similar potency, and both are inactivated by the same amino-terminal cleavage.

A still shorter natural fragment, 1-29, is the sermorelin sequence and retains full activity.

Why the longer backbone

The carboxyl-terminal residues add helix-stabilising contacts with the receptor extracellular domain and slow degradation from the carboxyl end. For a drug, the longer backbone gave the best affinity and stability the natural sequence offered, and the single amino-terminal modification addressed the one weakness all forms share. Shortening the backbone, as sermorelin did, saved synthesis cost at the expense of affinity.

The 44-residue amide is therefore the natural hormone at its most stable, plus one acyl group.

Why it is here

Because the two natural forms are part of the record of the hormone and explain a design choice. It describes biochemistry and no use of the pack.

Tesamorelin is supplied by REVIVE LAB UAE for laboratory research use only, with identity by mass spectrometry and purity by HPLC for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
Tesamorelin Pack20 mgAED 1010In 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 two forms?

Both come from the same 108-residue precursor. Cleavage after residue 44 with amidation gives the major form; cleavage at an internal basic site gives the 40-residue acid. Their relative proportions vary by tissue. Both bind the receptor with similar affinity and release growth hormone with similar potency, and both are inactivated by the same amino-terminal cleavage.

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.

Tesamorelin 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.