Dr. Muscle is a workout app that positions itself as a "pocket personal trainer," using AI to build and continuously adjust strength-training programs based on what a user actually lifts. Exercise scientist Dr. Carl Juneau founded the company in 2016 after finishing his PhD.
Instead of a fixed program, Dr. Muscle logs every set a user completes and recalculates the next session's weights, reps, and rest periods based on that performance history, aiming to auto-progress or auto-deload a lift the way an in-person trainer would adjust a session on the fly. In January 2026 the company began rolling out Dr. Muscle X, a progressive-web-app rebuild of the original app, in early access.
Dr. Muscle fits people who lift weights and want programming decisions handled for them rather than following a static spreadsheet. A free plan with limited features is available after an initial trial period; the premium subscription costs $48.99 a month for full auto-adjusting programming and unlimited exercise logging.
