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phase 2Growth Hormone

Tabimorelin

Also known as: NN703, NNC 26-0161

Tabimorelin is an oral non-peptide growth hormone secretagogue developed by Novo Nordisk that reached phase 2 clinical trials for adult growth hormone deficiency before development was discontinued. It demonstrated dose-dependent GH release and IGF-1 elevation in clinical studies, but failed to achieve sustained clinical endpoints. Its development contributed to understanding the limitations of oral GHS-R1a agonists for chronic GH replacement.

3 cited references·4 researched benefits

Quick Answer

Tabimorelin (NN703) is an oral growth hormone secretagogue developed by Novo Nordisk that reached phase 2 trials for adult GH deficiency. It produced dose-dependent GH release and IGF-1 increases in clinical studies but was discontinued due to insufficient sustained efficacy for GH deficiency treatment. Its development revealed that intermittent GHS-R1a stimulation may not adequately replicate continuous GH replacement, contributing to the scientific understanding of oral GH secretagogue limitations.

Key Facts

Mechanism
Tabimorelin is an orally bioavailable, non-peptide agonist of the growth hormone secretagogue receptor 1a (GHS-R1a). It stimulates pituitary somatotrophs via Gq/11-coupled signaling, increasing intracellular calcium and triggering GH release. As a small molecule, it achieves oral bioavailability without the peptide stability challenges of endogenous ghrelin. However, the pulsatile GH release produced by intermittent oral dosing differs pharmacodynamically from the sustained GH replacement achieved by recombinant GH injections.
Research Status
phase 2
Half-Life
~2–3 hours
Primary Use
Growth Hormone
Table of Contents

Benefits

  • Oral GH stimulation — demonstrated oral bioavailability with dose-dependent GH release in clinical trialsmoderate
  • IGF-1 elevation — increased circulating IGF-1 levels during treatment periodsmoderate
  • Convenience — oral dosing eliminates daily injection burden of recombinant GH therapymoderate
  • Preserved pulsatility — stimulates physiological pulsatile GH release rather than continuous exogenous supplypreliminary

Dosage Protocols

RouteDosage RangeFrequencyNotes
Oral5–25 mgOnce dailyStudied in phase 2 trials at 5, 10, and 25 mg once daily. Development discontinued by Novo Nordisk. Not commercially available.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Appetite increase — ghrelin receptor activation stimulates hunger in some subjectscommon
  • Paresthesia — tingling or numbness reported in some trial participantsrare
  • Fluid retention — mild edema related to GH-mediated effectsrare
  • Headache — occasional mild headache during dosing periodscommon

Frequently Asked Questions

Why was tabimorelin development discontinued?
Novo Nordisk discontinued tabimorelin after phase 2 trials showed that while it produced acute GH responses, it did not reliably achieve sustained IGF-1 normalization equivalent to daily recombinant GH injections. The intermittent, pulsatile GH release from oral GHS-R1a stimulation was insufficient for treating GH deficiency, where patients need consistent IGF-1 levels for clinical benefit. Additionally, tachyphylaxis (reduced response with repeated dosing) may have limited long-term efficacy.
What did we learn from the tabimorelin program?
The tabimorelin program revealed key limitations of oral GH secretagogues: (1) pulsatile GH release from secretagogues differs from the sustained pharmacokinetics of recombinant GH; (2) GHS-R1a desensitization may limit chronic efficacy; (3) patients with severe GH deficiency (damaged pituitary somatotrophs) may not respond adequately to secretagogues that require functional pituitary tissue. These insights shaped the development of subsequent GH secretagogue programs.
How does tabimorelin compare to other discontinued GH secretagogues?
Several oral GH secretagogues have been developed and discontinued: tabimorelin (Novo Nordisk), capromorelin (Pfizer, discontinued for humans but approved veterinary), and various others. MK-677 (ibutamoren) advanced furthest in human trials but also never achieved FDA approval. The pattern suggests fundamental challenges with oral GHS-R1a agonists for GH replacement, though the ghrelin pathway remains validated for other applications like appetite stimulation and diagnostic testing.
Could tabimorelin be useful for indications other than GH deficiency?
The ghrelin pathway is relevant to appetite stimulation (cancer cachexia), sarcopenia, functional recovery after hip fracture, and metabolic regulation. While tabimorelin was tested primarily for GH deficiency, its mechanism could theoretically benefit these other conditions. However, with development discontinued and no current sponsor, tabimorelin is unlikely to be repurposed. Other oral ghrelin agonists (anamorelin, macimorelin) have been developed for alternative indications.

References

  1. 1
    Tabimorelin (NN703), a novel orally active growth hormone secretagogue: results of a phase II trial in adult GH deficiency(2002)PubMed ↗
  2. 2
    Oral growth hormone secretagogues: clinical development and limitations(1999)PubMed ↗
  3. 3
    Growth hormone secretagogue receptor agonists: a drug discovery perspective(2007)PubMed ↗

Latest Research

Last updated: 2026-02-19