Peptide profile · Growth Hormone
Tabimorelin
An investigational oral growth hormone secretagogue that stimulates GH release through ghrelin receptor activation, though development was discontinued due to drug interaction concerns.
Written & reviewed by Michael Carroll · Research, Peptide Initiative
Typical dose
1.5 mg/kg per day (3 mg/kg first and last dose)
Half-life
Several hours (exact human half-life not published; dose-dependent pharmacokinetics)
Bioavailability
Orally active with dose-dependent bioavailability (increases at higher doses)
Molecular weight
528.7 g/mol
Evidence level
Moderate human trials
01 · Compound profile
Scientific & efficacy data
Molecular formula
C32H40N4O3
Primary benefits
Potent, dose-dependent GH elevation starting at 1.5 mg/kg; significant IGF-1 increases at higher doses, supporting anabolism and GH-mediated benefits
Non-injection, oral formulation enhances user compliance and avoids injection-site reactions; suitable for extended-use protocols
Does not significantly elevate prolactin, cortisol, or ACTH at most doses; however, CYP3A4 inhibition and rapid tolerance development limit overall safety and efficacy profile
Novo Nordisk A/S
Amino acid sequence
N/A — Non-peptide small molecule (peptidomimetic growth hormone secretagogue)02 · Dosing
How much do I take?
1.5 mg/kg per day (3 mg/kg first and last dose) · once daily
Oral: Taken by mouth as a capsule, tablet, or liquid.
Bioavailability Varies by compound — many peptides are largely broken down in the gut, so little reaches the blood intact; some small molecules absorb well.
Best time to take
Evening or before bedtime (mirrors natural GH secretion patterns)
With food?
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 stacking
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.
＋ Increase if
- +You've tolerated the current dose for the recommended period without significant side effects
- +Therapeutic goals haven't been met at the current dose level
- +Your healthcare provider recommends dose escalation based on your response
- +Lab work or clinical assessments support a higher dose
－ Decrease if
- −Side effects are bothersome or impacting daily life despite management strategies
- −You experience any signs of an adverse reaction
- −Lab results indicate the need for dose reduction
- −Your healthcare provider recommends a lower dose based on your response
✓ Signs of right dose
- ✓Therapeutic goals being met with minimal side effects
- ✓Stable and consistent response to treatment
- ✓Lab values or clinical markers trending in the right direction
- ✓Good tolerance with manageable or absent side effects
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03 · Suitability
Is this right for me?
Best for stimulating growth hormone production in healthy individuals & exploring gh secretagogue mechanisms in research settings
Do not use if
Use with caution if
Not sure?
Compare Tabimorelin with similar peptides to find the best fit for your goals.
04 · Administration
How do I use it?
Oral (capsule or solution)
Reconstitution — what you need
Example
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.
Route
Not applicable — oral formulation only
Best sites
Technique
- 01Tabimorelin is taken orally in capsule or solution form, not via injection
- 02Take with or without food as directed
- 03Swallow capsules whole with water
- 04Follow exact dosing instructions on prescription label
Storage · before reconstitution
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.
Storage · after reconstitution
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.
Signs of degradation
05 · Safety
Is it safe?
5 common side effects · 1 serious
Tabimorelin is an oral GHS-R agonist with preclinical and early clinical data indicating dose-dependent appetite stimulation (potentially problematic for weight-conscious users) and transient blood glucose elevation due to GH's insulin-antagonistic effects. No human safety database exists beyond Phase 1/2 studies—efficacy and long-term safety profile in humans remain incompletely characterized. Potential risks include carpal tunnel syndrome (documented with chronic GH therapy), arthralgias, and theoretical tumor growth acceleration, though these are extrapolated from GH physiology rather than directly observed in limited human exposure.
Safety information is limited to rat and limited human Phase 1/2 data; no Phase 3 efficacy trials have been completed. GH secretagogue class effects (appetite stimulation, glucose dysregulation) are expected based on mechanism, but individual tolerability variability is substantial. Long-term human safety data beyond 12 weeks does not exist—any use should be considered experimental with careful clinical monitoring including fasting glucose and IGF-1 levels.
Common side effects · experienced by some users
Stop and seek help if
- ×Severe or worsening side effects that don't improve with dose adjustment or supportive care
- ×Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- ×Your healthcare provider recommends discontinuation based on your clinical response
- ×Development of any new medical condition that may be contraindicated with Tabimorelin
- ×Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- ×Abnormal lab results or clinical markers that suggest adverse effects
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.
With other peptides
- ✓GHRH (synergistic GH stimulation, though not extensively studied in humans) — May be used together under medical guidance.
- ✓Resistance training (enhances GH-mediated muscle growth) — May be used together under medical guidance.
- ✓Adequate protein intake and overall nutrition (supports GH-driven anabolism) — May be used together under medical guidance.
With medications
- !Strong CYP3A4 inhibitors (itraconazole, ritonavir, clarithromycin) — tabimorelin itself inhibits CYP3A4, creating bidirectional interaction risks — Use with caution—discuss with your healthcare provider.
- !CYP3A4 substrates (statins, certain antiarrhythmics, immunosuppressants) without careful monitoring — Use with caution—discuss with your healthcare provider.
With supplements
- ✓Multivitamins — Generally safe to take alongside Tabimorelin. Space doses apart if taking oral formulations to ensure optimal absorption.
- ✓Electrolyte supplements — Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
06 · Effectiveness
How do I know it's working?
Moderate human trials · first signs first dose
Evidence level
Moderate human trials
(Phase 1-2)
How it works
Tabimorelin is a growth hormone secretagogue peptide that stimulates your pituitary gland to release more growth hormone. It works by binding to ghrelin receptors in the brain and pituitary, triggering natural growth hormone pulses. This helps increase muscle mass, bone density, and metabolic rate while reducing fat accumulation.
Tabimorelin is a synthetic growth hormone-releasing peptide (GHRP) that selectively binds to and activates the ghrelin receptor (GHSR-1a) located on somatotroph cells in the anterior pituitary gland and on GHRH neurons in the hypothalamus. This binding activates Gq/11 G protein-coupled receptor signaling pathways, leading to increased intracellular calcium mobilization and activation of PKC signaling cascades. In somatotrophs, GHSR-1a activation directly stimulates growth hormone (GH) release through enhanced exocytosis of GH granules. Simultaneously, Tabimorelin activates hypothalamic GHRH neurons while inhibiting somatostatin (SRIF)-secreting neurons, creating a dual mechanism for enhanced GH secretion. The peptide also exhibits modest appetite-stimulating properties through NPY/AgRP pathway activation in the lateral hypothalamus. Unlike exogenous GH injection which suppresses endogenous GH secretion through negative feedback, Tabimorelin maintains natural pulsatile GH secretion patterns.
What to expect
First dose
What you might notice
- •GH elevation occurs within 30–60 minutes;
- •peak typically at 60–90 minutes post-dose
What's normal
- •Full integration of Tabimorelin into physiological systems is established
- •Long-term Tabimorelin response remains personalized to your physiology
- •Tabimorelin tolerance is well-maintained with consistent dosing
What's next
- →Maintain your established Tabimorelin protocol for sustained benefits
- →Continue periodic monitoring to confirm Tabimorelin efficacy
- →Review comprehensive Tabimorelin response with your provider
Days 1–3
What you might notice
- •Mild headache, nausea, or dizziness may emerge;
- •appetite begins to increase
What's normal
- •Tabimorelin is achieving sufficient receptor engagement
- •Initial mechanism of Tabimorelin is taking effect
- •Early transient effects from Tabimorelin administration are resolving
What's next
- →Maintain consistent Tabimorelin administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Days 4–7
What you might notice
- •Continued GH elevation on each dose;
- •tolerance may begin to develop in some individuals (seen clinically as reduced GH peak)
What's normal
- •Tabimorelin is achieving sufficient receptor engagement
- •Initial mechanism of Tabimorelin is taking effect
- •Early transient effects from Tabimorelin administration are resolving
What's next
- →Maintain consistent Tabimorelin administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Weeks 2–4
What you might notice
- •Sustained appetite stimulation;
- •modest gains in muscle or lean mass possible with adequate protein and training;
- •GH response plateaus or declines in some users
What's normal
- •Tabimorelin is now achieving steady-state pharmacokinetics
- •Measurable changes aligned with Tabimorelin's mechanism may appear
- •Initial adjustment effects typically resolve by this point
What's next
- →Maintain Tabimorelin dosing exactly as established
- →Track progress toward intended outcomes in detail
- →Review lab work or biomarker changes with your healthcare team
Weeks 4–6
What you might notice
- •End of typical cycle;
- •benefits plateau or decline as tolerance fully develops;
- •discontinuation recommended per protocol
What's normal
- •Tabimorelin is now achieving steady-state pharmacokinetics
- •Measurable changes aligned with Tabimorelin's mechanism may appear
- •Initial adjustment effects typically resolve by this point
What's next
- →Maintain Tabimorelin dosing exactly as established
- →Track progress toward intended outcomes in detail
- →Review lab work or biomarker changes with your healthcare team
Days after discontinuation
What you might notice
- •GH levels return to baseline within 24–48 hours;
- •appetite normalizes;
- •no rebound adverse effects
What's normal
- •Tabimorelin response patterns are emerging
- •Initial Tabimorelin response is consistent with mechanism expectations
- •Early tolerance development to Tabimorelin is not expected
What's next
- →Assess whether Tabimorelin response aligns with expectations
- →Plan next steps based on initial Tabimorelin tolerance and response
- →Establish baseline monitoring for Tabimorelin response tracking
Not seeing results? Common reasons
- •Not at therapeutic dose yet—initial doses are for building tolerance, not maximum effect
- •Insufficient time at target dose—most compounds need several weeks to show full benefits
- •Inconsistent dosing schedule—regular, consistent use is crucial for optimal results
- •Individual variation in response—genetics, metabolism, and other factors affect outcomes
- •Underlying conditions or medications interfering with absorption or effectiveness
- •Improper storage leading to degraded product—always verify proper storage conditions
Key research
07 · Questions
Frequently asked
Is tabimorelin the same as ghrelin?+
No. Tabimorelin is a synthetic, non-peptide small molecule (peptidomimetic) that mimics ghrelin's effects by binding to the ghrelin receptor. Ghrelin is the natural hormone produced by stomach cells. Tabimorelin is stronger and longer-lasting than native ghrelin.
Why was tabimorelin development discontinued?+
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.
How quickly does tolerance develop to tabimorelin?+
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.
Can I safely combine tabimorelin with my cholesterol medication (statin)?+
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.
Is tabimorelin available as a commercial product?+
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.
How does tabimorelin compare to other growth hormone secretagogues like MK-677 or ipamorelin?+
All three are non-peptide ghrelin receptor agonists. Tabimorelin is highly selective for GHSR and potently stimulates GH, but carries significant CYP3A4 inhibition risks. MK-677 (Ibutamoren) has a better drug-interaction profile and is more widely used. Ipamorelin is another oral alternative with less published CYP3A4 liability. Tabimorelin's development was discontinued due to the drug-interaction risk.
08 · Further reading
History & related research
History · since 1998
The Danish pill that almost beat the peptide
Tabimorelin is a peptidomimetic drug created by Novo Nordisk. It mimics how peptides work but comes as an easy-to-swallow pill.
Read the full history of Tabimorelin