tl;dr: Non-animal testing methods (NAMs)—including organs-on-chips, organoids, and computational "digital twins"—are gaining regulatory traction after the 2022 FDA Modernization Act 2.0 and subsequent NIH and EU moves to phase out mandatory animal testing. Studies suggest NAMs can outperform animal models in specific cases (e.g., Emulate's liver chip caught 7/8 human-toxic drugs that passed animal trials), but validation remains expensive and head-to-head comparisons are scarce. The bigger obstacle is cultural inertia: researchers, reviewers, and funders still expect animal data, making adoption more a change-management problem than a technical one.