Use corrective makeup (such as contouring) to redraw shadows and highlights on the skin to instantly create the visual illusion of more voluminous pectorals.

noli's read

From an aesthetic perspective, this technique relies on well-established principles of visual perception. Observational studies in cognitive science, notably the work of Mingoia and Todd on the perception of relief through shading, confirm that our brain naturally uses variations of light and shadow to evaluate three-dimensional volumes. However, the use of makeup remains a purely ephemeral trick. Regarding the development of actual muscle, reference meta-analyses, such as those by Brad Schoenfeld in the Journal of Strength and Conditioning Research, demonstrate that only progressive overload through resistance training stimulates hypertrophy. Makeup therefore offers an instantaneous visual shortcut validated by optical physics. Nevertheless, it obviously lacks any evidence of efficacy for increasing physical strength or actual long-term muscle mass.

the sources

No named source held this one up — that absence is part of the verdict.