Foundation

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.

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

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

Needed for red blood cells and nerve function; especially relevant for vegans and vegetarians.

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

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.

Zinc supports immune function and tissue repair; athletes lose some in sweat. Helpful if your diet is low in it.

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.

Collagen peptides studied for joint comfort; several trials report less activity-related joint pain at around 5g a day, though effects are modest.

Involved in fat metabolism; supplements haven't consistently improved endurance performance.