What supplements are recommended for an otherwise healthy adult who runs three to five times per week to support inflammation control, bone and muscle health, iron balance, and endurance?

Best Supplements for Runners

For healthy adults running 3-5 times per week, vitamin D supplementation (1000-2000 IU daily) is the single most evidence-based recommendation, while iron supplementation should only be used if deficiency is confirmed through blood testing. 1, 2

Vitamin D: The Priority Supplement

Vitamin D is essential for bone health, skeletal muscle function, immunity, and injury prevention in athletes. 1 Athletes are at particular risk for deficiency if training indoors, living above the 35th parallel, or covering skin extensively during outdoor training. 1

• Aim for 25-OH-vitamin D levels >50 nM to protect bone health. 1
• Daily maintenance supplementation of 1000-2000 IU vitamin D3 is recommended, with dosing adjusted based on season and sun exposure. 1
• If severe deficiency is identified, the American College of Sports Medicine recommends 50,000 IU weekly for 8 weeks, then transitioning to 1000-2000 IU daily maintenance. 2
• Recheck vitamin D levels after 3 months of supplementation. 2

Iron: Test Before Supplementing

Iron supplementation should NOT be routine—only supplement if deficiency is confirmed through serum ferritin and hemoglobin testing. 1

When Iron Supplementation Is Appropriate:

• If iron deficiency is confirmed, ferrous sulfate 200 mg twice daily (providing 60-80 mg elemental iron) is the recommended treatment. 2, 3
• Take iron supplements in the morning with vitamin C (250-500 mg or 80 mg) to enhance absorption. 2, 3
• Continue supplementation for 3 months after hemoglobin normalizes to replenish iron stores. 2, 3
• Expect hemoglobin to rise approximately 2 g/dL after 3-4 weeks of treatment. 2

Critical Pitfalls to Avoid:

• Do NOT take calcium supplements at the same time as iron—they impair iron absorption. 2, 3
• Avoid tea or coffee within one hour of taking iron supplements as they inhibit absorption. 3
• Iron deficiency may impair high-intensity and endurance performance, but supplementation without confirmed deficiency is not beneficial. 1

Calcium: Food First, Supplement If Needed

Athletes should consume 1500 mg calcium daily to optimize bone health, ideally through dietary sources. 1

• The gut cannot absorb more than 500 mg calcium at once, so spread intake throughout the day. 1
• Include four portions of calcium-rich dairy foods (milk, yogurt, cheese) daily. 1
• A 500 mg calcium supplement may be needed if consuming less than one dairy portion daily. 1
• Remember: calcium supplements must be taken at different times than iron supplements. 2

What About Other Supplements?

Anti-Inflammatory Supplements (Curcumin, Tart Cherry):

• Preliminary evidence suggests curcumin or tart cherry juice may reduce inflammation and delayed onset muscle soreness (DOMS). 4
• However, these are not essential for healthy runners and evidence is less robust than for vitamin D. 4

Omega-3 Fatty Acids:

• May reduce inflammation and support recovery from mild traumatic brain injury, but not specifically proven for routine running performance. 4

Creatine Monohydrate:

• May improve recovery from intense training and adaptation to exercise, but is more relevant for high-intensity, power-based activities than endurance running. 4

General Multivitamins:

• Due to lack of benefit/safety evidence in healthy athletes, general use of dietary supplements should be restricted. 1
• A multi-nutrient supplement containing B vitamins, amino acids, and anti-inflammatory plant extracts reduced IL-6 and improved perceived energy in middle-aged active adults. 5

Dietary Strategies Over Supplementation

Focus on whole foods first: 1

• Include iron-rich foods (red meat, poultry, fish, beans, leafy greens) with vitamin C-rich foods to enhance absorption. 2, 3
• Consume adequate fluids: women need at least 1.6 L and men need at least 2 L daily. 1
• Spread protein intake throughout the day to support muscle recovery. 1

The Bottom Line Algorithm:

1. Start vitamin D supplementation (1000-2000 IU daily) for all runners. 1
2. Get iron status tested (serum ferritin and hemoglobin) before considering iron supplementation. 1, 2
3. Ensure adequate calcium intake (1500 mg daily) through diet, supplement only if needed. 1
4. Avoid routine multivitamin or supplement use without specific indication. 1
5. Prioritize whole food sources of nutrients over supplements whenever possible. 2, 3