Those that contain betaine help with aerobic, endurance training. Betaine increases carnitine in muscle cells to enhance energy production. It also helps pump up your muscles and permits high volume/reps in weight training.
Likewise, supplemental nitrate sources enhance blood flow and nutrient delivery to working muscles in activities that are cardiovascularly demanding.
Practice due diligence and select accordingly.
If you are looking to give a slight edge to your exercise training, you might consider investing in a pre-workout supplement. Do consider addingprotein powders to your diet as well. Pre-workout supplements help to optimize muscle growth and hypertrophy. They increase the capacity for performing more reps, enhancing muscular power, provides focus, reduces fatigue and energizes you for a hard sweat sesh.
Be discerning which supplement you choose. Select products manufactured by credible companies. Check out the nutritional facts, and opt for ingredients such as beta alanine, caffeine and creatine. Also, keep in mind what training modality you typically take part in. Do you prefer cardio, weights or HIIT? Above all, be safe and enjoy your workout!