Macimorelin

Macimorelin is normally used to diagnose growth hormone deficiency (GHD) in adults. It was FDA approved in 2017 under the name Macrilen.

It's an oral growth hormone secretagogue (GHS) that stimulates the pituitary gland to release growth hormone. It is not actual growth hormone. It is used in growth hormone stimulation testing to measure how much growth hormone the body produces after taking the medication. It can also be used more frequently to help boost the body’s natural GH production.

Macimorelin is an innovative medication designed to help with growth hormone-related issues. Ghrelin is a natural hormone that stimulates the release of growth hormone. It works by activating ghrelin receptors (similar to Ipamorelin) in the pituitary gland which stimulates a growth hormone (GH) pulse. It mimicks natural growth hormone secretion which supports various functions, including:

• Metabolism regulation – helping the body process proteins, fats, and sugars efficiently.
• Muscle and bone health – promoting muscle growth, strength, and bone density.
• Overall hormone balance – improving pituitary function and regulating other hormones.

Key Benefits of Optimized Growth Hormone with Macimorelin

Body Composition & Fat Loss

• Increased muscle mass
• Faster fat burning, especially belly fat
• Helps maintain lean muscle during weight loss

Athletic Performance & Recovery

• Faster muscle recovery after workouts
• Improved strength and endurance
• Better joint and tendon health
• Protein synthesis: It encourages muscle growth and maintenance, improving overall body composition.

Anti-Aging Effects

• Firmer skin, fewer wrinkles (due to collagen production)
• Increased energy levels
• Improved sleep quality
• Sarcopenia (age-related muscle loss): Macimorelin may help older adults maintain muscle strength and function.
• GH plays a key role in bone formation and repair, reducing the risk of osteoporosis and supporting fracture healing, especially in older adults.

 Cognitive Function

• Better memory and focus
• Improved mood
• Helps reduce feelings of anxiety and depression

Libido & Sexual Health

• Increased sex drive
• Improved sexual performance (for both men & women)

Metabolism & Blood Sugar Regulation

• Helps control blood sugar
• Lowers risk of insulin resistance
• Fat breakdown (lipolysis): GH promotes fat loss, which may support weight management and help with obesity.
• Glucose control: It could improve insulin sensitivity, making it beneficial for people with type 2 diabetes or metabolic syndrome.

Cardiovascular Benefits

• Early research suggests that Macimorelin might help improve heart function and blood pressure, making it useful for cardiovascular health.

Pharmacology

Macimorelin stays active in the body for a few hours (half-life 4.1 hours). Most of the drug clears out within 24 hours. It stimulates growth hormone release within 45 minutes to 90 minutes after taking it, with peak GH levels around 60 minutes.

Macimorelin is taken once daily (5/7 days per week), usually in the morning. It is available in 0.5 mg and 1 mg oral capsules. For optimal results, take Macimorelin after an 8-hour overnight fast and at least 2 hours before eating. This timing ensures the best absorption and effectiveness.

Macimorelin is a promising treatment for growth hormone deficiency, metabolic issues, muscle loss, and bone health. With its ability to mimic natural hormone secretion, it has the potential to improve overall well-being in various conditions.

Research

Herodes M, Anderson LJ, Shober S, Schur EA, Graf SA, Ammer N, Salas R, Marcelli M, Garcia JM. Pilot clinical trial of macimorelin to assess safety and efficacy in patients with cancer cachexia. J Cachexia Sarcopenia Muscle. 2023 Apr;14(2):835-846. doi: 10.1002/jcsm.13191. Epub 2023 Mar 1. PMID: 36860137; PMCID: PMC10067502.

Urwyler SA, Lustenberger S, Drummond JR, Soares BS, Vogt DR, Ammer N, Yuen KCJ, Ribeiro-Oliveira A, Christ-Crain M. Effects of oral macimorelin on copeptin and anterior pituitary hormones in healthy volunteers. Pituitary. 2021 Aug;24(4):555-563. doi: 10.1007/s11102-021-01132-9. Epub 2021 Feb 22. PMID: 33615399; PMCID: PMC8270818.

Lissy M, Demmel V, Sachse R, Ammer N, Kelepouris N, Ostrow V. Thorough QT/QTc Study Evaluating the Effect of Macimorelin on Cardiac Safety Parameters in Healthy Participants. Clin Pharmacol Drug Dev. 2021 May;10(5):494-501. doi: 10.1002/cpdd.872. Epub 2020 Sep 22. PMID: 32961034; PMCID: PMC8246819.

Klaus B, Sachse R, Ammer N, Kelepouris N, Ostrow V. Safety, tolerability, pharmacokinetics, and pharmacodynamics of macimorelin in healthy adults: Results of a single-dose, randomized controlled study. Growth Horm IGF Res. 2020 Jun;52:101321. doi: 10.1016/j.ghir.2020.101321. Epub 2020 Apr 15. PMID: 32325373.