Is MC4R useful for weight loss?

MC4R (melanocortin 4 receptor) is a key regulator of appetite and energy balance. Rare loss-of-function mutations cause monogenic obesity, but common variants found in consumer DNA tests have very small effect sizes. For most people, an MC4R genotype does not meaningfully predict weight loss success or guide specific interventions. Evidence is largely mechanistic or from GWAS with modest associations; clinical utility for weight management is low. Direct-to-consumer tests often overstate the impact. Caveat: In cases of severe early-onset obesity, clinical MC4R sequencing may be warranted, but for general weight loss, this test is not recommended. Lifestyle factors (calorie balance, exercise, sleep) remain the primary drivers of weight change.