Complex sentence: Some commercial organizations promote chromium (III) picolinate as an aid to body development for athletes and as a means of losing weight, but a number of studies have failed to demonstrate an effect of chromium (III) picolinate on either muscle growth or fat loss.
Split into simpler sentences: Some commercial organizations promote chromium (III) picolinate as an aid to body development for athletes and as a means of losing weight. But a number of studies have failed to demonstrate an effect of chromium (III) picolinate on either muscle growth or fat loss.