Hair clock for circadian medicine

Researchers used gene‑expression patterns from a single hair‑follicle sample plus machine learning to infer a person’s current circadian phase. The method maps the activity of ~17 clock‑related genes to a time‑of‑day reading, potentially replacing slow, clinic‑bound protocols like serial melatonin sampling. — If validated and scaled, this cheap, ambulatory circadian test could change how medicine times treatments, how employers schedule shift work, and how public health manages sleep‑related risks.