How long does pre-workout last? Gym bunnies feeling a little low on energy before exercising sometimes look for a boost before training. Newsweek explores the different types and how they work.

If you've vowed to hit the gym in 2025, you may encounter "pre-workouts": powders promising bulked-up muscles and increased endurance. We look at the evidence behind their claims.

Pre-workout powders usually contain amino acids, B vitamins, creatine used to increase muscle mass and boost strength, artificial sweeteners and a whole lot of caffeine.. Most brands have anywhere ...