Ipamorelin vs Tabimorelin
A uniquely selective growth hormone booster that tells your pituitary to release more GH without messing with your cortisol or other hormones—making it the 'clean' choice among growth hormone peptides.
An investigational oral growth hormone secretagogue that stimulates GH release through ghrelin receptor activation, though development was discontinued due to drug interaction concerns.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Ipamorelin
200–200 mcg
Tabimorelin
1.5–1.5 mg/kg
Frequency
Ipamorelin
Multiple times daily
Tabimorelin
Once daily
Administration
Ipamorelin
Subcutaneous injection
Tabimorelin
Oral (capsule or solution)
Cycle length
Ipamorelin
8-12 weeks
Tabimorelin
4-6 weeks
Onset speed
Ipamorelin
Moderate (1-2 weeks)
Tabimorelin
Moderate (1-2 weeks)
Evidence level
Ipamorelin
Moderate human trials (Phase 1-2)
Tabimorelin
Moderate human trials (Phase 1-2)
Benefit ratings
GH Selectivity
Recovery Support
Safety Profile
Growth Hormone Stimulation
Convenience & Compliance
Selectivity & Safety Profile
Compound specifications
Ipamorelin
Molecular formula
C38H49N9O5
Molecular weight
711.85 g/mol
Half-life
2 hours
Bioavailability
High when injected subcutaneously
CAS number
170851-70-4
Tabimorelin
Molecular formula
C32H40N4O3
Molecular weight
528.7 g/mol
Half-life
Several hours (exact human half-life not published; dose-dependent pharmacokinetics)
Bioavailability
Orally active with dose-dependent bioavailability (increases at higher doses)
CAS number
193079-69-5
Dosing compared
Ipamorelin
Subcutaneous
100 mcg per injection
2-3 times daily · 4-8 weeks
Conservative entry dose; Ipamorelin is a selective GH secretagogue with a ~2 hour half-life, so doses are split through the day [1][2]. Used in research and practice to assess tolerance before titrating up.
200 mcg per injection
2-3 times daily · 8-12 weeks
Most commonly cited research/practice dose; gives a meaningful pulsatile GH release without raising cortisol or prolactin at standard doses [1][2].
300 mcg per injection
3 times daily · 8-12 weeks
Upper end of the commonly used range; total daily exposure split across three injections. Used in practice by experienced users [1].
Tabimorelin
Oral
1.5 mg/kg per day (3 mg/kg first and last dose)
Once daily · 7-day study course
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].
Best suited for
Ipamorelin
Clean GH Boost Seekers
If you want the benefits of increased growth hormone without spiking cortisol or other stress hormones, Ipamorelin is uniquely selective. Unlike GHRP-2 or GHRP-6, it won't raise your cortisol levels even at doses 200 times higher than needed for GH release.
Recovery-Focused Athletes
Ipamorelin shines for athletes who want better recovery between training sessions. The GH boost helps repair muscle tissue faster, and since it doesn't mess with other hormones, you can use it consistently without the rollercoaster effects.
Anti-Aging Enthusiasts
Growth hormone naturally declines as we age, contributing to muscle loss, fat gain, and reduced vitality. Ipamorelin offers a gentle way to restore more youthful GH levels without the risks of actual HGH therapy.
Those Recovering from Steroid Use
Research shows Ipamorelin can help counteract the muscle and bone-weakening effects of glucocorticoid medications. If you've been on steroids for medical reasons, this peptide may help you rebuild what you've lost.
Tabimorelin
- Stimulates growth hormone release from the pituitary gland through ghrelin receptor activation
- Orally active—no injections required, making it convenient for daily use
- Dose-dependent growth hormone and IGF-1 elevation at therapeutic doses
- Does not significantly raise ACTH, cortisol, or prolactin at most doses, showing better selectivity than some competing GH-releasing peptides
- Well-tolerated in short-term human studies with generally mild adverse effects
Side effects
Ipamorelin
Common
- Mild headache
- Injection site reactions
- Water retention
- Increased appetite
Uncommon
- Tingling in hands or feet
- Joint stiffness
Serious
- Allergic reaction
Tabimorelin
Common
- Headache
- Nausea
- Appetite stimulation
- Dizziness
- Dry mouth
Serious
- Drug-drug interactions via CYP3A4 inhibition
Safety & evidence
Ipamorelin
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Ipamorelin's main selling point is that it raises growth hormone without raising cortisol or ACTH — two stress hormones that similar peptides do raise. That was shown in pigs, and it held even at doses more than 200 times higher than the amount needed to raise growth hormone [1]. It has not been checked in people. The two published human studies measured ipamorelin and growth hormone only; neither one assayed cortisol, ACTH or prolactin [2][3]. Most of what we know about safety in people comes from a single trial in patients recovering from bowel surgery. 114 people took part: 56 got ipamorelin through an IV for up to seven days, and 58 got a placebo. Most side effects were mild to moderate, and were the kind you would expect after surgery [3]. Serious problems happened at about the same rate in both groups — roughly 1 in 6 either way (17.9% on ipamorelin, 15.5% on placebo). But three things were more common on ipamorelin: low potassium in about 1 in 8 people versus about 1 in 30 on placebo (12.5% vs 3.4%), trouble sleeping in about 1 in 9 versus about 1 in 19 (10.7% vs 5.2%), and high blood sugar at discharge in about 1 in 7 versus about 1 in 12 (14.3% vs 8.6%) [6]. Two people taking ipamorelin died. Both had colon cancer surgery, and in both cases the surgical join in the bowel leaked afterward. Nobody on the placebo died. The FDA says it is unclear whether those deaths had anything to do with ipamorelin — but it pointed to them, along with the potassium and blood sugar differences, when it recommended in October 2024 against letting pharmacies compound ipamorelin [6].
Contraindications
- Active cancer or history of cancer
- Pregnancy or breastfeeding
- Pituitary disorders or tumors
- Known allergy to peptide components
- Children and adolescents (growth plates still open)
Tabimorelin
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
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.
Contraindications
- Active or history of carcinomas (ghrelin receptor agonists may stimulate growth of certain tumors)
- Concurrent use of potent CYP3A4 substrates due to risk of dangerous drug-drug interactions
- Untreated thyroid dysfunction
- Uncontrolled diabetes
Which is right for you?
Choose Ipamorelin if...
- Muscle recovery and growth
- Anti-aging and vitality
- Body composition improvement
- Sleep quality enhancement
Choose Tabimorelin if...
- Stimulating growth hormone production in healthy individuals
- Exploring GH secretagogue mechanisms in research settings
- Patients preferring oral administration over injections