Vitamins

Sodium is the main electrolyte lost in sweat; replacing it supports fluid balance in long or hot sessions.

An electrolyte involved in muscle and nerve function; sweat losses are much smaller than sodium's.

Magnesium supports muscle and nerve function and sleep; many athletes fall short of the recommended intake. Supplementing helps mainly when intake is low. Glycinate and malate forms are well absorbed and gentle on the stomach.

An electrolyte and bone mineral; sweat losses are small compared with sodium.

Needed for immune function and healthy skin and gut lining; most people get enough from diet.

Supports immune function and acts as an antioxidant; moderate doses may reduce colds during heavy training, while very high doses may blunt training adaptations.

Vitamin D supports bone, muscle and immune health; deficiency is common in athletes who train indoors or live far from the equator.

An antioxidant vitamin; most people get enough from diet, and high doses offer no performance benefit.

Involved in energy metabolism and making neurotransmitters; supplementing helps only if intake is low.

A B vitamin involved in turning food into energy; supplementing helps only if your diet is short on it.