Most testosterone boosters do not raise testosterone enough in healthy men to meaningfully affect muscle, strength or libido.
L-carnitine has a real function in the body, but its effect as a fat burner is small and often overstated.
Ab exercises strengthen the muscles, but visible abs mainly require a calorie deficit and lower body fat.
The eccentric phase matters for mechanical tension, technique and building muscle mass.
Cardio increases energy expenditure, but sustainable fat loss still depends on a long-term calorie deficit.
A well-set calorie deficit helps you lose fat without unnecessary loss of muscle or energy.
Full or long range of motion often provides a better stimulus than heavier partial repetitions.
BCAAs are not bad amino acids, but they rarely add practical value when your intake of high-quality protein is already sufficient.
Long static stretching immediately before strength or explosive work can temporarily reduce force production.