Growth hormone
An oral growth hormone booster that reached human trials before development stopped over drug-interaction concerns.
Start here
Tabimorelin is an investigational compound taken by mouth that prompts the pituitary (the master hormone gland at the base of the brain) gland to release more growth hormone by activating the ghrelin (the hunger hormone) receptor, the same switch used by the body's natural hunger hormone. In short-term human studies it raised growth hormone and IGF-1 (a growth signal your liver releases in response to growth hormone) levels in a dose-dependent way and was generally well tolerated. Its development was discontinued over drug interaction concerns, and it remains a research compound, not an FDA-approved medicine.
Tabimorelin works on the same switch in your brain and pituitary (the master hormone gland at the base of the brain) gland that ghrelin, your body's natural hunger hormone, uses. When it flips that switch, the pituitary releases pulses of your own growth hormone, much the way it does naturally. At the same time, it nudges the brain signals that promote growth hormone release and quiets the ones that hold it back. Because the hormone still comes from your own pituitary in natural pulses, this is different from injecting growth hormone itself, which causes the body to shut down its own production.
Used to enhance growth hormone levels in conditions associated with GH deficiency or age-related GH decline, promoting muscle mass, bone density, and metabolic improvements.
Tabimorelin is a lab-made growth hormone-releasing peptide (GHRP). It attaches to and switches on the ghrelin (the hunger hormone) receptor (GHSR-1a), found on somatotroph cells (the growth-hormone-making cells) in the front part of the pituitary (the master hormone gland at the base of the brain) gland, and on GHRH neurons (nerve cells that release the brain's growth hormone starter signal) in the hypothalamus (the brain region that runs your hormone system). This sets off Gq/11 G protein signaling (a chain of messages inside the cell), which raises calcium inside the cell and turns on PKC signaling (another chain of internal messages). In somatotroph cells, switching on GHSR-1a directly triggers growth hormone (GH) release by pushing out stored GH granules. At the same time, tabimorelin activates GHRH neurons in the hypothalamus and shuts down neurons that release somatostatin (SRIF, a hormone that holds GH back). This gives two routes to more GH. The peptide also has a modest appetite-boosting effect through the NPY/AgRP pathway (appetite-driving nerve cells) in the lateral hypothalamus. Injected GH shuts down your body's own GH release through negative feedback (the body senses enough and turns production off). Tabimorelin does not; it keeps the natural pulse-like pattern of GH release.
Evidence check
Some human studies
It has been tested in people, but only in small or early-stage studies. Promising, but not yet proven the way an approved medicine is.
Every numbered marker on this page links to one of the 3 sources at the bottom.
Growth Hormone Stimulation
Strong, dose-dependent rise in growth hormone (GH) starting at 1.5 mg/kg; IGF-1 rises significantly at higher doses, supporting muscle-building (anabolic) and other GH-driven benefits
Convenience & Easy to Stick With
Non-injection, oral formulation enhances user compliance and avoids injection-site reactions; suitable for extended-use protocols
Precise Action & Safety
Does not significantly raise prolactin, cortisol, or ACTH (a hormone that tells the body to make cortisol) at most doses. However, its blocking of CYP3A4 (a liver enzyme that processes many drugs) and the rapid tolerance that builds up limit its overall safety and usefulness
The most-asked question
The research-reported range is 1.5 mg/kg, once daily.
Growth hormone deficiency research
1.5 mg/kg per day (3 mg/kg first and last dose)
Dose used in GH-deficient adults (1 week course, 3 mg/kg first and last dose) 2; significant GH release seen at 3 mg/kg and above in single-dose healthy-volunteer studies 1.
The ceiling: 500 (as determined by your healthcare provider based on individual response and tolerance)
Reconstitution, in plain words
Peptides usually arrive as a freeze-dried powder in a small vial. “Reconstitution” just means adding sterile water back in so you can measure a dose. Here's how it works for Tabimorelin:
Tabimorelin comes in pre-measured doses or forms. Follow the exact dosing instructions on your prescription label. No reconstitution or mixing is typically required for this formulation.
Use Tabimorelin exactly as prescribed. Each unit contains the labeled amount. Your healthcare provider will determine the appropriate dose based on your individual needs and response.
Three quick questions — your vial, your water, your dose — and it tells you the exact syringe mark. “Find dose amount” is preloaded with Tabimorelin's recorded schedule.
Timing
Evening or before bedtime (mirrors natural GH secretion patterns)
Take Tabimorelin on an empty stomach for optimal absorption, or with a light meal if GI discomfort occurs. Avoid heavy meals within 30 minutes of dosing.
If combining Tabimorelin with other peptides or supplements, space administrations by at least 15-30 minutes when possible. Consult with a healthcare provider before combining with prescription medications.
The honest list
These show up most often. They usually fade as your body adjusts.
Mild to moderate headache onset within 1-2 hours of dosing, typically frontal or temporal. Reported in ~30% of users in early clinical trials. Usually improves with repeated dosing as body tolerates ghrelin (the hunger hormone) stimulation.
What to do Take with food to slow absorption and reduce intensity. Ibuprofen or acetaminophen (500 mg) effective if needed. Stay well-hydrated—dehydration worsens headaches. Divide dose (AM + PM instead of single dose) if tolerated. Most headaches diminish by day 3-5 with continued use.
Mild to moderate nausea begins 30 minutes to 2 hours after a dose. It reflects the drug acting on the brain's nausea-trigger area. About 20-25% of users report it. It is usually mild and clears on its own, but it can be distressing.
What to do Take the dose right after eating, not on an empty stomach, to cushion your stomach. Ginger (a 500 mg capsule or tea) is highly effective and natural. Ondansetron (4-8 mg) or metoclopramide (10 mg) work if ginger is not enough. Stay well hydrated. Most users report the nausea fades by day 3-5 as the brain's nausea-trigger area gets used to the drug.
Because the drug mimics ghrelin (the hunger hormone), hunger rises steadily starting on day 2-3. Hunger usually peaks on days 7-14. The effect runs through hunger-control brain pathways (NPY/AgRP) in the hypothalamus (the brain region that runs your hormone system). It is expected and is part of how the drug works.
What to do If weight gain is undesired, portion control at meals is essential—use smaller plates and eat slowly. Increase protein proportion to promote satiety. Avoid keep snacks available in visible locations. Time dosing away from peak hunger (early morning on empty stomach, not pre-meal). Increase aerobic activity to offset caloric surplus. This effect usually stabilizes by week 3-4.
Mild to moderate lightheadedness or a spinning feeling begins 30-90 minutes after a dose. It likely reflects short-term changes in the heart and blood vessels from raised growth hormone and ghrelin-receptor activation. It is usually mild and passes.
What to do Avoid driving or operating heavy machinery for 1-2 hours after dosing. Sit or lie down if dizziness occurs. Stay well-hydrated. Slow positional changes—rise from sitting slowly. Blood pressure monitoring may reveal mild changes. Dizziness usually diminishes by day 2-3 as tolerance develops.
Dry mouth (xerostomia) builds gradually within 1-4 hours after a dose. It comes from the drug acting on the ghrelin (the hunger hormone) receptor, which affects the salivary glands, and from a faster metabolism. It is usually mild but can be bothersome.
What to do Increase overall fluid intake to 2.5-3 liters daily. Sip water frequently throughout day. Sugar-free gum/lozenges stimulate saliva production. Avoid caffeinated beverages (worsen dehydration). Mouth rinse with water before bed. Most cases resolve by day 3-7 with consistent hydration.
Rare, but if any of these happen, stop and contact a medical professional.
Tabimorelin is a mechanism-based irreversible CYP3A4 inhibitor. Combining with CYP3A4 substrates (statins, immunosuppressants, antiarrhythmics, certain antiretrovirals) causes dangerous elevation of those drug levels. This critical liability was the primary reason Novo Nordisk discontinued development.
What to do CRITICAL: Comprehensive medication review required before starting. Absolutely avoid strong CYP3A4 inhibitors (itraconazole, ritonavir, clarithromycin). Use rosuvastatin or pravastatin instead of atorvastatin/simvastatin. If combining with CYP3A4 substrates is unavoidable, therapeutic drug monitoring required. Pharmacist consultation highly recommended.
Week by week
Is it right for you?
Tabimorelin should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Use with caution—discuss with your healthcare provider.
Use with caution—discuss with your healthcare provider.
May be used together under medical guidance.
May be used together under medical guidance.
May be used together under medical guidance.
Generally safe to take alongside Tabimorelin. Space doses apart if taking oral formulations to ensure optimal absorption.
Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Tabimorelin is an oral drug that switches on the growth hormone secretagogue (a compound that prompts your body to release growth hormone) receptor (the same receptor ghrelin (the hunger hormone) uses). Animal and early human data show appetite rises with the dose (a problem if you are watching your weight) and blood sugar rises briefly because growth hormone works against insulin. No human safety record exists beyond early Phase 1/2 studies, so its long-term safety and effectiveness in people are not well understood. Possible risks include carpal tunnel syndrome (a nerve problem in the wrist seen with long-term growth hormone), joint pain, and a theoretical speeding-up of tumor growth. These are borrowed from what growth hormone does, not directly seen in the small number of people who have taken it.
Safety information is limited to rat studies and small early human studies 123. No Phase 3 trials of effectiveness have been completed. Appetite increase and blood sugar problems are expected for this drug class based on how it works, but how well individuals tolerate it varies a lot. There is no human safety data beyond 12 weeks. Any use should be treated as experimental, with careful medical monitoring including fasting blood sugar and IGF-1 (a growth signal your liver releases in response to growth hormone) levels.
Keeping it good
Store Tabimorelin in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
Once reconstituted, Tabimorelin should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Not our opinion — the published record
2000
This study investigated the properties and effects of Tabimorelin, contributing to our understanding of its mechanism of action and potential therapeutic applications.
Zdravkovic M, et al.
2003
This study investigated the properties and effects of Tabimorelin, contributing to our understanding of its mechanism of action and potential therapeutic applications.
Svensson J, et al.
2001
This study investigated the properties and effects of Tabimorelin, contributing to our understanding of its mechanism of action and potential therapeutic applications.
Agersø H, et al.
Your questions
No. Tabimorelin is a lab-made small molecule, not a true peptide. It is built to copy a peptide's action (a peptidomimetic). It mimics ghrelin (the hunger hormone)'s effects by attaching to the ghrelin receptor, the docking site ghrelin uses. Ghrelin is the natural hormone made by stomach cells. Tabimorelin is stronger and longer-lasting than natural ghrelin.
Development was halted primarily due to tabimorelin's mechanism-based inhibition of CYP3A4, a major liver enzyme. This creates serious drug-drug interaction risks—tabimorelin can dangerously elevate levels of medications metabolized by CYP3A4 (statins, some immunosuppressants, certain antiarrhythmics, etc.). Additionally, clinical trials showed limited efficacy in GH-deficient patients, with only 11% achieving meaningful GH peaks, combined with rapid tolerance development.
Clinical data show that GH response declines significantly after just 1 week of continuous daily dosing in many individuals, a phenomenon called tolerance. This is why most protocols recommend cycling: 4–6 weeks on, 2–3 weeks off, or using intermittent dosing schedules.
This is a serious concern. Tabimorelin inhibits CYP3A4, the enzyme that metabolizes most statins. Combining them could raise statin levels dangerously, increasing risk of muscle breakdown (rhabdomyolysis) or liver injury. You MUST consult a physician and pharmacist before combining. Switching to a statin not metabolized by CYP3A4 (e.g., pravastatin, rosuvastatin) may be necessary.
No. Tabimorelin (NN-703) never received FDA approval and development was discontinued. It is not commercially available in any country and is only available within research or investigational settings.
All three are described in the source as non-peptide drugs that act like ghrelin (the hunger hormone) to raise growth hormone (GH). Tabimorelin targets the ghrelin receptor very precisely and strongly raises GH. But it can block CYP3A4 (a liver enzyme that processes many drugs), which makes dangerous drug interactions a real risk. MK-677 (Ibutamoren) has a better interaction record and is more widely used. Ipamorelin is another option with less published CYP3A4 risk. Tabimorelin's development was stopped because of this interaction risk.
3 sources
Every numbered marker on this page points to one of these. Same sources, same numbering as the Tabimorelin research profile on Peptide Initiative.
Want the deep science?
Every claim on this page traces back to the research database behind Peptide Initiative — studies, citations, clinical trial data, and the technical detail we deliberately left out here.
Open the research profileThis guide is education, not medical advice. Tabimorelin is a research compound that is not FDA-approved for human use. Talk to a clinician before taking anything.
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