AI Muscle Generator — free, in your browser
Change the build in the photo. Same person, same pose, different physique.
Open the full AI Muscle GeneratorSee what the paid models add
Getting a usable result
Fitted clothing or a bare torso gives the change something to read against. A loose hoodie hides everything you asked for.
Small steps look real; large ones start bending the clothes and the background around them.
A prompt that works
Give the person in the photo a more muscular, athletic gym physique with broader shoulders and defined arms, keeping the same fitted shirt, face, and pose. Photorealistic, natural.
That is the same prompt the AI Muscle Generator on Kavel starts you with, so you can run it here first and take it over there when you want the higher-resolution model.