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Growth hormone axis

Mecasermin

Also called Increlex, rhIGF-1, recombinant human IGF-1

Mecasermin is a lab-made copy of human IGF-1, the hormone that growth hormone normally tells the liver to make. It is FDA-approved (as Increlex) for children who stay very short because their bodies cannot make enough IGF-1. Its main risk is low blood sugar.

FDA-approvedApproved by the FDA for at least one use after large human trials.

All printable flashcards

Drawn from its published sequence: 70 residues, one bead each. Dashed arcs are ring bonds.

Overview

Mecasermin is a lab-made copy of human IGF-1, the hormone that growth hormone normally tells the liver to make. It is FDA-approved (as Increlex) for children who stay very short because their bodies cannot make enough IGF-1. Its main risk is low blood sugar.

How it works

Established: replaces IGF-1, which binds the IGF-1 receptor to drive bone and tissue growth. Because IGF-1 also acts like insulin, it can lower blood sugar.

What research shows

  • Approved on the basis of growth data in children with severe primary IGF-1 deficiency (see FDA label).

Doses studied in people

An FDA-labeled pediatric dose exists for Increlex, but the label could not be opened to verify it for this profile; see the official prescribing information.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Weekly protocol

How the schedule looks week by week. Each chart says where it comes from: a prescribing label, a clinical trial, or a protocol commonly reported online.

Increlex label titration

Prescribing label

One week

D1D2D3D4D5D6D7

Twice daily, within 20 minutes before or after a meal or snack · Subcutaneous injection

Dose by week

0.04–0.08 mg/kg twice dailyStarting · wk 1
Raise by 0.04 mg/kg per dose (if tolerated for 1 week), up to 0.12 mg/kg twice dailyTitration · wk 2+
Course
Ongoing
Note
Weight-based; maximum 0.12 mg/kg twice daily. Give with food to lower the risk of low blood sugar.
Source
INCRELEX (mecasermin) prescribing information (FDA, revised 07/2025)

Reference only, not a recommendation. Label and trial schedules were set for specific patients under medical supervision. Use the calculator only to understand the arithmetic.

Safety

  • Low blood sugar (hypoglycemia) is the main known risk of IGF-1 therapy.
  • Specific label warnings and adverse-event rates were not re-verified for this profile; consult the Increlex prescribing information.
  • Not a substitute for growth hormone in GH-deficient patients.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Storage and stability

Refrigerated, per label.

General lab handling, not instructions for personal use. See Storage and stability.

History

Approved by FDA in 2005 as Increlex (NDA 021839) for severe primary IGF-1 deficiency in children.

Common questions

Is mecasermin FDA-approved?

Yes. FDA approved it in 2005 as Increlex for children with severe primary IGF-1 deficiency, and it is prescription-only 1. As an approved product it is not on FDA's 503A compounding nomination list 3.

What was approval based on?

Growth data in children with severe primary IGF-1 deficiency, as described in the FDA label 1.

What dose is used?

The FDA label sets a pediatric dose, but it could not be opened to verify it for this profile 1. The official Increlex prescribing information is the source for dosing.

What are the main risks?

Low blood sugar is the main known risk, because IGF-1 also acts like insulin 1. It is not a substitute for growth hormone in people who lack growth hormone 1.

How is it stored?

The label says it is kept refrigerated 1.

Is mecasermin banned in sport?

Yes. WADA prohibits it at all times and names IGF-1/mecasermin in its growth factors class 2.

Related compounds

Growth hormone axisPreclinical onlyFlashcard

IGF-1 LR3

Long R3 IGF-1 · LR3-IGF-1

IGF-1 LR3 is a lab-modified form of insulin-like growth factor 1, the hormone that carries out many of growth hormone's effects.

Growth hormone axisFDA-approvedFlashcard

Tesamorelin

Egrifta · Egrifta SV

Tesamorelin is a lab-made version of the body's growth-hormone-releasing hormone.

Sources

  1. Drugs@FDA: INCRELEX (mecasermin) NDA 021839 FDA label
  2. WADA 2026 Prohibited List (in force 1 January 2026) Regulatory
  3. FDA: Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (categories list, updated May 14, 2026) Regulatory

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.