Optimal energy levels depend on many factors. Adequate sleep, optimal hydration, a robust diet filled with plants, and frequent physical activity all contribute to high energy levels. When it comes to specific nutrients, the B vitamins are best known for their role in energy production. Possibly lesser-known but critical for energy is the mineral iron. Iron is responsible for circulating oxygen throughout the bloodstream to all of the body’s organs and tissues. Neurotransmitters like serotonin, acetylcholine, and dopamine also play a role in energy levels, and the production of these neurotransmitters depends on the B vitamins and vitamin C.