A study published in The American Journal of Clinical Nutrition (July 2022), found that the samsung watches arevery accurate.
They compared the watches with two reference methods (DXA scan and a "duplicate laboratory-grade octapolar bioelectrical impedance analysis"). They found the watches had a 97-98% accuracy.
"After systematic correction, smart-watch BIA devices are capable of stable, reliable, and accurate body composition measurements, with precision comparable to but lower than that of laboratory measures. These devices allow for measurement in environments not accessible to laboratory systems, such as homes, training centers, and geographically remote locations."
