Capromorelin vs Ipamorelin
An oral ghrelin agonist originally developed by Pfizer that stimulates growth hormone and appetite. FDA-approved for veterinary use (Entyce and Elura) and investigated in human trials for age-related muscle wasting and appetite support.
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
Capromorelin
10–10 mg
Ipamorelin
200–200 mcg
Frequency
Capromorelin
Once daily
Ipamorelin
Multiple times daily
Administration
Capromorelin
Oral (capsule or tablet)
Ipamorelin
Subcutaneous injection
Cycle length
Capromorelin
4-6 weeks
Ipamorelin
8-12 weeks
Onset speed
Capromorelin
Moderate (1-2 weeks)
Ipamorelin
Moderate (1-2 weeks)
Evidence level
Capromorelin
Moderate human trials (Phase 1-2)
Ipamorelin
Moderate human trials (Phase 1-2)
Benefit ratings
GH & IGF-1 Stimulation
Physical Function
Oral Convenience
GH Selectivity
Recovery Support
Safety Profile
Compound specifications
Capromorelin
Molecular formula
C28H35N5O4
Molecular weight
505.6 g/mol
Half-life
1-2.4 hours in humans
Bioavailability
Good oral bioavailability
CAS number
193273-66-4
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
Capromorelin
Oral
3 mg
Twice daily · Initial weeks
One of the lower doses tested in the year-long study in older adults; raised growth hormone and IGF-1 [1].
10 mg
Once daily at bedtime · Ongoing
A simple once-daily bedtime dose used in the human trial that improved lean body mass [1].
10 mg
Twice daily · Up to 12 months in the trial
The highest daily amount studied in older adults, giving the largest gains in muscle mass and physical function [1].
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
Capromorelin
Age-Related Muscle Wasting
Capromorelin showed significant improvements in physical function — including tandem walk and stair climb — in elderly adults, making it a strong candidate for combating sarcopenia.
Appetite Stimulation
As an FDA-approved veterinary appetite stimulant, capromorelin has extensive real-world evidence for boosting food intake and body weight in mammals.
Growth Hormone Research
One of the best-studied oral ghrelin agonists with human Phase 2 data, offering researchers a well-characterized tool for studying GH/IGF-1 pathways.
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
Capromorelin
Common
- Appetite stimulation
- Fluid retention and weight gain
Uncommon
- Joint and muscle aches
- Fatigue or lethargy
- Peripheral edema (swelling)
Serious
- Hyperglycemia
Ipamorelin
Common
- Mild headache
- Injection site reactions
- Water retention
- Increased appetite
Uncommon
- Tingling in hands or feet
- Joint stiffness
Serious
- Allergic reaction
Safety & evidence
Capromorelin
Evidence level
Moderate human trials (Phase 1-2)
FDA status
FDA approved for this use
Safety overview
Capromorelin was generally well-tolerated in Phase 2 human trials involving nearly 400 elderly participants. Most side effects were mild to moderate. Its FDA-approved veterinary use provides additional long-term safety data in mammalian species.
Contraindications
- Active cancer or history of cancer (GH may stimulate growth)
- Uncontrolled diabetes or severe metabolic disorders
- Severe liver or kidney disease
- Pregnancy and lactation
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 Capromorelin if...
- Stimulating growth hormone production in elderly adults
- Supporting appetite and weight gain in wasting conditions
- Improving muscle mass and physical performance
- Anti-aging and longevity optimization
Choose Ipamorelin if...
- Muscle recovery and growth
- Anti-aging and vitality
- Body composition improvement
- Sleep quality enhancement