Macimorelin

Also known as: Macrilen, oral ghrelin receptor agonist

Wellness

In plain English

Macimorelin is an FDA-approved oral medicine used as a test, not a treatment: a single dose stimulates growth hormone release, and doctors measure the response to diagnose adult growth hormone deficiency. It offers a simpler, safer alternative to older stimulation tests. It is taken by mouth after fasting, and serious side effects are uncommon.

The science

Macimorelin is an orally active ghrelin/GHS-R agonist. In a multicenter, randomized, two-way crossover validation trial (Garcia et al., JCEM 2018), single-dose oral macimorelin matched the insulin tolerance test for diagnosing adult growth hormone deficiency (about 92% sensitivity and 96% specificity at a 5.1 ng/mL cutoff), was reproducible (~97%), and had no serious adverse events. It received FDA approval (Macrilen) as a diagnostic agent for adult GH deficiency. This is a diagnostic use; it is not a growth-hormone therapy. QT-interval prolongation and interacting drugs warrant attention.

References

• Garcia JM et al., J Clin Endocrinol Metab 2018