Growth hormone
An oral appetite-and-growth-hormone stimulator — FDA-approved for dogs and cats (Entyce, Elura), and tested in people for age-related muscle loss.
Start here
Capromorelin is an oral compound, originally developed by Pfizer, that mimics ghrelin — the hunger hormone — to raise appetite and growth hormone. It is FDA approved only for animals: as Entyce for appetite in dogs and Elura for weight loss in cats with chronic kidney disease 45. In humans it has been tested in a phase 2 trial in older adults 1, but it is not approved for human use.
Capromorelin copies ghrelin, the hormone that makes you feel hungry. It acts in two places: in the hypothalamus — the brain's appetite control center — where it stimulates hunger, and in the pituitary (the master hormone gland at the base of the brain) gland, where it triggers release of growth hormone 4. In a trial in older adults it raised IGF-1 (a growth factor the liver makes in response to growth hormone) and increased lean body mass 1.
Capromorelin is approved in veterinary medicine to stimulate appetite in dogs, and it has been tested in people for conditions that cause appetite loss and muscle wasting — including cancer-related wasting (cachexia), anorexia nervosa, and the age-related loss of muscle called sarcopenia. Because it boosts both appetite and growth hormone at the same time, researchers see it as a possible tool for managing poor appetite and muscle loss in aging and illness.
Capromorelin copies ghrelin (the hunger hormone). It attaches to the ghrelin receptor (GHS-R1a) in the hypothalamus (the brain's appetite center), which raises appetite, and in the pituitary (a gland at the base of the brain), which raises growth hormone release. 4 It binds the human receptor tightly, with a Ki of 7 nM (a lower number means a tighter grip). 6 The liver enzymes CYP3A4 and CYP3A5 break it down. In dogs it peaks within about 50 minutes and has a half-life (the time for half the drug to leave the body) of about 1.2 hours. 4 In older adults, every dose raised the nighttime peak of growth hormone (most with the least frequent dosing) and caused a steady, dose-related rise in IGF-1 (a growth signal made in the liver). 1
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 6 sources at the bottom.
Growth hormone (GH) and IGF-1 boost
Potent, dose-dependent growth hormone and IGF-1 elevation through oral ghrelin receptor agonism, supporting anabolic and metabolic pathways
Physical Function
In the pooled treatment groups of a phase 2 trial in older adults, tandem walk improved by 0.9 seconds at 6 months and stair climb improved by 12 months, versus placebo.
Oral Convenience
No injections or reconstitution needed — simple oral capsule with proven bioavailability and predictable pharmacokinetics
The most-asked question
The research-reported range is 10 mg, once daily. Studies used different doses for different situations — find yours:
Initial assessment, GH/IGF-1 support
3 mg
One of the lower doses tested in the year-long study in older adults; raised growth hormone and IGF-1 (a growth signal your liver releases in response to growth hormone) 1.
Lean body mass, Appetite stimulation
10 mg
A simple once-daily bedtime dose used in the human trial that improved lean body mass 1.
Muscle building, Advanced protocols
10 mg
The highest daily amount studied in older adults (20 mg/day). The trial reported results for the pooled treatment groups, not the largest gains for this dose 1.
The ceiling: 20 mg daily (10 mg twice a day), the highest dose studied in the human phase 2 trial 1
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 Capromorelin:
No reconstitution math needed — take the prescribed number of capsules or measured liquid dose as directed.
Standard dose is 10 mg once daily. For liquid form, use the provided measuring syringe to draw the exact volume.
Three quick questions — your vial, your water, your dose — and it tells you the exact syringe mark. “Find dose amount” is preloaded with Capromorelin's recorded schedule.
Timing
Morning or evening, taken consistently at the same time each day
Can be taken with or without food; taking with a light meal may reduce nausea
If combining with other GH-supporting supplements, space doses by at least 1-2 hours
The honest list
These show up most often. They usually fade as your body adjusts.
Increased hunger and food intake. This is the intended mechanism for veterinary use but may be unwanted for some human users. Appetite increase is typically strongest in the first 2-3 weeks, then may stabilize or gradually decrease.
What to do If weight gain is undesired, monitor caloric intake closely and maintain consistent meal timing. Increase protein consumption to support lean muscle development. Consider timing dosing away from meal prep or dining triggers. Drink more water to help with satiety.
Mild to moderate water retention and lean weight gain due to GH effects. May cause temporary increase in body weight, typically 2-5 lbs over a 4-6 week cycle. Most weight gained is lean mass rather than fat, though some water retention is expected.
What to do Monitor body composition rather than just scale weight. Reduce sodium intake slightly to minimize water retention. Maintain adequate hydration. Most fluid retention resolves within 1-2 weeks post-cycle. Use compression garments if peripheral edema (fluid retention and swelling) is bothersome.
Worth knowing about, but most people never see these.
Mild arthralgia or myalgia reported in some users, typically resolving with continued use or dose adjustment. Can reflect rapid tissue remodeling as GH stimulates anabolic (muscle-building) processes in musculoskeletal tissue. Usually mild and transient.
What to do Light stretching and mobility work help relieve stiffness. NSAIDs like ibuprofen are effective if pain interferes with daily activities. Ensure adequate sleep (7-9 hours) as GH-driven recovery requires rest. Proper warm-up before exercise reduces severity. Most resolve by week 3-4 of use.
Some users report mild tiredness, particularly during the first week of dosing as the body adjusts to elevated GH. This is often accompanied by increased deep sleep and may reflect enhanced anabolic (muscle-building) processes occurring during rest.
What to do Increase sleep duration slightly (8-9 hours instead of 7) to support the elevated metabolic and anabolic (muscle-building) state. Ensure adequate caloric intake—underfeeding while on GH secretagogues (compounds that prompt a hormone's release) paradoxically increases fatigue. B-vitamins and iron levels should be checked if fatigue persists. Most users report increased energy by week 2-3 as body adapts.
Fluid accumulation in extremities due to GH's vascular permeability effects. Typically mild and reversible, affecting hands, feet, or ankles. Usually appears during weeks 2-3 and resolves post-cycle. More common at doses ≥10 mg.
What to do Elevate legs when sitting or resting. Light compression socks or sleeves help manage swelling. Increase water intake paradoxically helps—it signals kidneys to reduce sodium retention. Reduce dietary sodium moderately. Mild diuretics (natural like caffeine or prescription) may be used under medical guidance. Swelling typically resolves 1-2 weeks after discontinuation.
Rare, but if any of these happen, stop and contact a medical professional.
Growth hormone (GH) raises blood sugar, which is a particular problem for people with diabetes or metabolic disorders. Capromorelin can raise fasting glucose by 5-15 mg/dL in some users. Insulin resistance (cells responding less to insulin) may develop, though this is usually reversible after the cycle.
What to do Check fasting glucose and HbA1c (your 3-month blood sugar average) before starting. Monitor blood glucose weekly during the cycle, especially if pre-diabetic or overweight. Increase aerobic exercise to 150+ min/week to improve insulin sensitivity (how well your body responds to insulin). Reduce refined carbohydrates and simple sugars. If fasting glucose rises above 110 mg/dL, reduce the dose or stop. Consult a healthcare provider before use if you have diabetes.
Week by week
Is it right for you?
Always consult a healthcare professional before starting or stopping any peptide or research compound. This information is for educational purposes only.
Capromorelin may raise blood sugar; watch it closely and adjust diabetes medications as needed
Both affect how the body handles sugar, so the risk of high blood sugar goes up when combined
Work together to release more growth hormone (GH), because GHRH (the brain signal that releases GH) acts through a different receptor
Does the same job, so it may add no benefit and could increase side effects
May modestly boost growth hormone release when combined with drugs that switch on the ghrelin (the hunger hormone) receptor (the hunger hormone's docking site)
Some evidence that melatonin supports growth hormone release during sleep; generally safe to combine
Capromorelin showed significant improvements in physical function — including tandem walk and stair climb — in elderly adults, making it a strong candidate for combating sarcopenia.
As an FDA-approved veterinary appetite stimulant, capromorelin has extensive real-world evidence for boosting food intake and body weight in mammals.
One of the best-studied oral ghrelin (the hunger hormone) agonists (compounds that switch a receptor on) with human Phase 2 data, offering researchers a well-characterized tool for studying GH/IGF-1 (a growth signal your liver releases in response to growth hormone) pathways.
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.
Human safety data comes primarily from a single Phase 2 trial (White et al., 2009) with 395 elderly subjects. Extensive veterinary safety data exists from FDA-approved products Entyce (dogs) and Elura (cats).
Keeping it good
The FDA-approved veterinary oral solutions are stored at or below 86°F (30°C). 45 There is no approved human product.
Not applicable — oral formulation does not require reconstitution. If liquid form, follow manufacturer storage instructions after opening.
Not our opinion — the published record
2009
In 395 older adults, oral capromorelin increased body weight (+1.4 kg) and lean body mass (+1.4 kg) and improved tandem-walk performance at 6 months versus placebo.
White HK, Petrie CD, Landschulz W, et al.
2024
Cats with kidney disease that got capromorelin gained weight and kept eating well for 56 days, while placebo cats didn't improve. The study proved that capromorelin's oral form works beautifully in mammals and has a solid safety record, leading to FDA approval of the product Elura for helping cats with failing kidneys.
Rathore M, Das N, Ghosh N, et al.
2025
Researchers designed a capromorelin derivative that's 100 times more powerful than the older version and works at oral doses as tiny as 0.1 mg/kg, making it remarkably potent. Even at these tiny doses, the new compound boosted growth hormone and helped young rats grow heavier and longer, proving capromorelin-based drugs have huge potential as oral growth hormone replacements.
Xu H, Liu M, Jia X, et al.
2025
A selective ghrelin receptor agonist (a drug that switches on the hunger-hormone receptor) used to stimulate appetite in dogs, 3 mg/kg by mouth once daily; not for use in humans. Do not use with allergy to it; use caution with liver problems (the liver enzymes CYP3A4/3A5 break it down), kidney problems, heart disease or dehydration (brief drops in heart rate and blood pressure) and diabetes (high blood sugar was reported). Field study: diarrhea 7.0%, vomiting 6.4%, extra drooling, increased thirst, raised BUN (a kidney blood marker). In dogs, half-life about 1.2 h and oral bioavailability (the share that reaches the blood) 44%. Store at or below 30 C.
Elanco US Inc. / U.S. FDA Center for Veterinary Medicine (DailyMed)
2025
For managing weight loss in cats with chronic kidney disease, 2 mg/kg by mouth once daily; not for use in humans. Brief drops in heart rate and blood pressure for up to 4 hours after dosing; high blood sugar (hyperglycemia) was reported in 6.8% vs 3.4% on placebo. In cats, feeding lowered Cmax (the peak blood level) by 55% and AUC (the total exposure) by 43%. Store at or below 30 C.
Elanco US Inc. / U.S. FDA Center for Veterinary Medicine (DailyMed)
2003
Pfizer Global Research and Development discovered capromorelin (CP-424391): it binds GHS-R1a (the ghrelin receptor) with a Ki of 7 nM (a lower number means a tighter grip), and its oral bioavailability (the share that reaches the blood) is 65% in rats and 44% in dogs. It was chosen as a development candidate for frailty (loss of muscle and strength) in older adults.
Carpino PA, Lefker BA, Toler SM, et al.
If this isn't the right fit
Your questions
No. Capromorelin is FDA-approved only for veterinary use: Entyce for dogs (2016) to stimulate appetite, and Elura for cats (2020) to manage weight in chronic kidney disease. Human Phase 2 clinical trials were conducted in elderly subjects showing safety and efficacy, but development for human use was not pursued to FDA approval. It remains a research compound for human applications.
Both are oral ghrelin (the hunger hormone) agonists (compounds that switch a receptor on) that stimulate GH and IGF-1 (a growth signal your liver releases in response to growth hormone). MK-677 has more human clinical data and is more widely available in research settings. Capromorelin was developed earlier (1999-2001) and has stronger veterinary evidence. Capromorelin has a shorter plasma half-life (1-2.4 hours) compared to MK-677's longer half-life (~24 hours), though both produce sustained GH stimulation. MK-677 may cause more hunger, while capromorelin's appetite effects are more moderate.
Capromorelin was developed by Pfizer and showed promise in human Phase 2 trials, but pharmaceutical development is driven by market opportunity and competitive landscape. By the time human efficacy was confirmed, the anti-aging market landscape had shifted. Aratana Therapeutics acquired the veterinary rights and successfully developed it for pet health, which has a clearer regulatory pathway and proven commercial success.
The phase 2 trial randomized 395 adults aged 65–84 to 10 mg three times a week, 3 mg twice a day, 10 mg each night, 10 mg twice a day, or placebo. 1 At 6 months, the pooled treatment groups gained 1.4 kg of body weight and 1.4 kg of lean mass and improved tandem walk (walking heel-to-toe); stair climb improved by 12 months. 1 Adverse events included fatigue, insomnia and small rises in fasting glucose, HbA1c (the 3-month blood sugar average) and insulin resistance, so glucose should be monitored. 1
Capromorelin is a small-molecule drug that mimics ghrelin (the hunger hormone) by activating the ghrelin receptor, GHS-R1a (growth hormone secretagogue (a compound that prompts your body to release growth hormone) receptor 1a), on nerve cells in the hypothalamus (the brain region that runs your hormone system). This triggers release of growth hormone-releasing hormone (GHRH). That signals the front part of the pituitary (the master hormone gland at the base of the brain) gland to release growth hormone, which then tells the liver to make IGF-1 (a growth signal your liver releases in response to growth hormone). Capromorelin also activates appetite centers in the hypothalamus, which explains its appetite-boosting effects in veterinary use.
The only human trial planned 2 years of daily dosing; it stopped early, with 315 people completing 6 months and 284 completing 12 months. 1 It did not use short cycles, and no study has tested cycling or post-cycle therapy. GH and IGF-1 (a growth signal your liver releases in response to growth hormone) effects depend on continued dosing.
Capromorelin is not approved for human use, and pregnant and lactating women should avoid it. For non-pregnant women interested in GH stimulation for muscle, bone, or anti-aging purposes, capromorelin theoretically works similarly in both sexes (GH effects are largely sex-neutral). However, given lack of human approval and female-specific safety data, medical supervision would be essential.
6 sources
Every numbered marker on this page points to one of these. Same sources, same numbering as the Capromorelin 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. Capromorelin is a research compound that is not FDA-approved for human use. Talk to a clinician before taking anything.
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