Hexarelin vs Ipamorelin
A powerful synthetic growth hormone secretagogue that tells your pituitary gland to release more growth hormone—plus it has remarkable heart-protective properties that make it stand out from other GH-boosting peptides.
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.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Hexarelin
1.5–3 mcg/kg
Ipamorelin
200–200 mcg
Frequency
Hexarelin
Once daily
Ipamorelin
Multiple times daily
Administration
Hexarelin
Subcutaneous injection
Ipamorelin
Subcutaneous injection
Cycle length
Hexarelin
8-12 weeks
Ipamorelin
8-12 weeks
Onset speed
Hexarelin
Rapid (hours to days)
Ipamorelin
Moderate (1-2 weeks)
Evidence level
Hexarelin
Moderate human trials (Phase 1-2)
Ipamorelin
Moderate human trials (Phase 1-2)
Benefit ratings
GH Release
Heart Health
Body Composition
GH Selectivity
Recovery Support
Safety Profile
Compound specifications
Hexarelin
Molecular formula
C47H58N12O6
Molecular weight
887.04 g/mol
Half-life
55-70 minutes
Bioavailability
High when injected subcutaneously
CAS number
140703-51-1
Ipamorelin
Molecular formula
C38H49N9O5
Molecular weight
711.85 g/mol
Half-life
2 hours
Bioavailability
High when injected subcutaneously
CAS number
170851-70-4
Dosing compared
Hexarelin
Subcutaneous
1.5-3 mcg/kg (approx. 100-200 mcg); ~100 mcg per injection in practice
Single dose in trials; 1-3 times daily in research practice · Acute test or open-ended practice use
Trial-validated subcutaneous GH-releasing doses of 1.5-3 mcg/kg in healthy volunteers [6]; the ~100 mcg fixed-dose practice figure aligns with the lower 1.5 mcg/kg trial dose.
Intravenous
1-2 mcg/kg (2 mcg/kg is maximally effective)
Single administration · Acute GH provocation
Trial-established near-maximal GH-releasing intravenous dose; produced a larger GH rise than equimolar GHRH in 12 healthy young volunteers [6].
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].
Best suited for
Hexarelin
Growth Hormone Optimization
Hexarelin is one of the most potent GH-releasing peptides available. It triggers strong, natural pulses of growth hormone from your pituitary, mimicking the way your body released GH when you were younger. This makes it ideal for those looking to restore youthful GH levels [6][8][9].
Heart Health Support
Unlike most other GH peptides, Hexarelin has direct cardioprotective effects through its binding to CD36 receptors in the heart. Research shows it can protect heart cells from damage, reduce inflammation, and even help prevent the scarring that occurs after heart injury [1][3][5].
Body Composition Improvement
The robust GH pulses triggered by Hexarelin enhance fat burning while supporting lean muscle. Research in obese models showed it increased lipid oxidation in fat tissue and reduced fat accumulation in the liver—all while improving insulin sensitivity [2].
Athletic Recovery
Growth hormone is essential for tissue repair and recovery. Hexarelin's ability to stimulate strong GH release makes it popular among athletes looking to bounce back faster from training. The improved sleep quality many users report also supports recovery.
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.
Side effects
Hexarelin
Common
- Increased hunger
- Water retention
- Tingling or numbness (paresthesia)
- Injection site reaction
Uncommon
- Headache
- Joint discomfort
Serious
- Allergic reaction
Ipamorelin
Common
- Mild headache
- Injection site reactions
- Water retention
- Increased appetite
Uncommon
- Tingling in hands or feet
- Joint stiffness
Serious
- Allergic reaction
Safety & evidence
Hexarelin
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Hexarelin has been studied in human trials and shows a generally favorable safety profile at research doses. [6][9] The most common effects relate to its strong GH-releasing action: temporary hunger spikes, [14] mild water retention, [15] and occasional tingling in the hands. Importantly, research suggests Hexarelin has direct cardioprotective effects that may add a margin of safety for cardiovascular health [1][5].
Contraindications
- Pregnancy or planning to become pregnant
- Currently breastfeeding
- Active cancer or history of cancer
- Known allergy to peptide components
- Uncontrolled diabetes
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)
Which is right for you?
Choose Hexarelin if...
- Growth hormone optimization
- Body composition improvement
- Heart health support
- Athletic recovery
Choose Ipamorelin if...
- Muscle recovery and growth
- Anti-aging and vitality
- Body composition improvement
- Sleep quality enhancement