Let me start by saying this waist trainer is a SWEAT MACHINE. The neoprene material traps heat like crazy—I literally had droplets rolling down my back after 20 minutes of light yoga. If you want intense thermal activity for workouts, this delivers.

The GOOD: The double Velcro adjustment is genius. As someone between sizes (5'6", 150lbs), I could cinch it tight enough to feel compression without restricting breathing. The boning strips legit improved my slouch during desk work—my coworkers asked if I'd gotten taller!

The NOT-SO-GOOD: That "seamless under clothes" claim? Nope. Even under baggy hoodies, there's visible bulk where the hooks overlap. And bending over to tie shoes feels like fighting against a stiff accordion.

PRO TIP: Size DOWN if between measurements. My medium arrived swimming on me despite the chart suggesting otherwise. The stretchy spandex means it accommodates smaller frames better than larger ones.

Best use case? Postpartum moms (the lumbar support is chef's kiss) or gym rats doing low-impact cardio. Skip it for deadlifts—the restricted motion made my form dangerously wobbly with weights.

Final verdict: 4/5 for sweat-inducing workouts and posture correction, but don't expect magic waist-shrinking or discreet everyday wear.