Both tools show you a picture of a change before you book. They answer very different questions, and the honest comparison mostly comes down to scope.
Crisalix builds a rotatable 3D model of your face or body from three phone photos, so you can turn it to profile. LookPrep renders onto the single photo you upload, which means the mirror view only, with no way to check the side.
Crisalix also covers far more: rhinoplasty, facelift, breast and body procedures, and injectables across 21 facial zones. Its professional terms require a licensed physician or aesthetic professional, and it has clinic tools such as patient records, booking and videoconferencing. LookPrep has none of that. It's self-serve, lips and lip flip only, with no clinician in the loop.
The vocabulary. Crisalix's lips menu has six presets, and its injectables guide uses percentage sliders rather than millilitres. LookPrep models eight named looks, each with a published standardisation grade, and quotes amounts in mL per product family, plus a separate lip flip option at 4 or 6 units.
Both say the same thing about their images in their own words. Crisalix calls them illustrative only. LookPrep calls them a planning visual, not a predicted result.
The full Crisalix and LookPrep comparison, row by row lists every source, including the rows Crisalix wins.
Sofia R., LookPrep