Tabimorelin
An oral pill meant to replace growth hormone injections, which raised GH in healthy men but did not help GH-deficient adults
Tabimorelin (NN703) is a small, peptide-like molecule from Novo Nordisk that activates the ghrelin receptor and makes the pituitary release growth hormone. It was developed as a tablet alternative to daily GH injections. In healthy men the GH response faded within a week, in GH-deficient adults it did no better than placebo after a week, and it strongly slowed the breakdown of other drugs. It was never approved.
What is it?
Growth hormone secretagogues act on the ghrelin receptor in the pituitary and hypothalamus to release the body's own growth hormone. Tabimorelin belonged to the late-1990s push for an oral one, which would spare people with GH deficiency daily injections.
Three problems surfaced in the human trials below. The GH response to repeated doses fell between day 1 and day 7 in healthy men. In adults with GH deficiency, a week of treatment gave GH responses no different from placebo once body size was accounted for. And it inhibits CYP3A4, a liver enzyme that breaks down many common drugs, almost doubling exposure to midazolam after a week.
Tabimorelin is still sold online, and anti-doping laboratories have developed urine tests for it alongside other ghrelin mimetics.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Published Research
Three human trials, a rat study and a doping-control method paper, read from their PubMed abstracts on October 4, 2026.
Seven days in healthy men
In a randomised, double-blind, placebo-controlled trial of once-daily oral doses from 1.71 to 6.86 mg/kg, GH release rose with dose on days 1 and 7, but fell overall from day 1 to day 7. IGF-1 rose more than with placebo at the three highest doses; FSH, LH and cortisol did not rise significantly.
Adults with GH deficiency
97 GH-deficient adults were randomised, double-blind, to a week of oral NN703 (3 mg/kg first and last dose, 1.5 mg/kg/day between) or placebo. The first dose raised GH more than placebo, but not after adjusting for body mass index, and after one week responses matched placebo.
A strong drug interaction
In 17 men, one dose of tabimorelin raised exposure to midazolam, a CYP3A4 substrate, by 64%, and a week of daily dosing raised it by 93%, confirming in people that it inhibits this major drug-metabolising enzyme.
Appetite and fat in rats
In lean rats, 18 days of oral tabimorelin increased food intake, fat mass and body weight, raised hypothalamic NPY and lowered POMC; the effects were blunted in rats lacking leptin signalling.
Doping-control tests
Anti-doping chemists identified 13 metabolites of tabimorelin, alongside those of capromorelin and macimorelin, and built the intact drugs into WADA-compliant screening methods for urine and plasma.
Side Effects & Contraindications
Reported Side Effects
From the trials above.
Contraindications & Cautions
Never approved, so no label exists.
Legal Status
Never approved; development discontinued.
Frequently Asked Questions
?What is tabimorelin?
An oral ghrelin-receptor agonist from Novo Nordisk, code NN703, developed to raise growth hormone without injections.
?Did tabimorelin work in GH-deficient adults?
Not in the 97-patient trial: after a week, GH responses were no different from placebo.
?Does tabimorelin interact with other drugs?
Yes. It inhibits CYP3A4 and nearly doubled exposure to midazolam after a week of dosing.
?Is it detectable in drug tests?
Anti-doping laboratories have built tabimorelin and its metabolites into screening methods.
References
- [pubmed] Zdravkovic M, et al. "The pharmacokinetics, pharmacodynamics, safety and tolerability following 7 days daily oral treatment with NN703 in healthy male subjects." Growth Horm IGF Res, 2001;11(1):41-8. PMID: 11437473.
- [pubmed] Svensson J, et al. "Oral administration of the growth hormone secretagogue NN703 in adult patients with growth hormone deficiency." Clin Endocrinol (Oxf), 2003;58(5):572-80. PMID: 12699438.
- [pubmed] Zdravkovic M, et al. "A clinical study investigating the pharmacokinetic interaction between NN703 (tabimorelin), a potential inhibitor of CYP3A4 activity, and midazolam, a CYP3A4 substrate." Eur J Clin Pharmacol, 2003;58(10):683-8. PMID: 12610745.
- [pubmed] Holm AM, et al. "Adipogenic and orexigenic effects of the ghrelin-receptor ligand tabimorelin are diminished in leptin-signalling-deficient ZDF rats." Eur J Endocrinol, 2004;150(6):893-904. PMID: 15191361.
- [pubmed] Lange T, et al. "Comprehensive insights into the formation of metabolites of the ghrelin mimetics capromorelin, macimorelin and tabimorelin as potential markers for doping control purposes." Biomed Chromatogr, 2021;35(6):e5075. PMID: 33458843.
Sources & Citations
Trials, the rat study and the doping-control paper from their PubMed abstracts, October 4, 2026; US and EU status from Drugs@FDA and the EMA list that day.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.