What is the recommended daily vitamin D (Vitamin D) supplement dose for a 15-year-old?

Vitamin D Supplementation for a 15-Year-Old

A 15-year-old should receive 600 IU of vitamin D daily from all sources (diet plus supplements), which is the standard recommendation for children and adolescents aged 1-18 years. 1

Standard Dosing Recommendation

• The recommended daily vitamin D intake for adolescents (ages 9-18 years) is 600 IU per day, as established by the Institute of Medicine and endorsed by multiple pediatric nutrition guidelines 1
• This dose applies to healthy adolescents without specific risk factors for vitamin D deficiency 1
• The 600 IU recommendation represents the total daily intake from all sources combined—both dietary intake and supplementation 2

Target Serum Levels

• The target serum 25(OH) vitamin D concentration should be maintained above 50 nmol/L (20 ng/mL) for bone health sufficiency 1
• Some guidelines suggest optimal levels between 30-80 ng/mL for broader health benefits, though evidence for non-skeletal benefits remains limited 3

Safety Considerations

• The tolerable upper intake level for adolescents aged 9-18 years is 4,000 IU per day, providing a wide safety margin 1
• Vitamin D toxicity is rare and typically requires daily doses exceeding 50,000 IU that produce serum levels above 150 ng/mL 1
• Prolonged daily intake up to 10,000 IU appears safe, though this far exceeds what is needed for a healthy adolescent 1

When Higher Doses May Be Needed

If vitamin D deficiency is documented (serum 25(OH)D < 50 nmol/L or 20 ng/mL):

• Provide additional supplementation beyond the standard 600 IU daily dose 1
• One common repletion regimen uses 50,000 IU weekly for 8 weeks, followed by rechecking serum levels 1
• Alternatively, add 1,000 IU daily to current intake if levels are between 20-30 ng/mL, then recheck in 3 months 1
• After repletion, maintain with standard age-appropriate dosing 1

Special Populations Requiring Monitoring

Adolescents in these categories should have their vitamin D status checked and may need higher supplementation:

• Those with limited sun exposure (dark-skinned individuals, those who remain indoors, or use extensive sun protection) 4, 5
• Adolescents with malabsorption conditions or chronic diseases 2
• Those on medications that interfere with vitamin D metabolism 1

Practical Implementation

• Vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) for supplementation 1, 3
• Daily dosing is standard for adolescents, though vitamin D has a long half-life (2 weeks to 3 months) and does not require strict daily adherence 1
• Sensible sun exposure can contribute to vitamin D status, though this varies greatly by season, latitude, and skin pigmentation 4, 5
• Most adolescents will not achieve adequate vitamin D from diet alone, as few foods naturally contain vitamin D 4, 5

Common Pitfalls to Avoid

• Do not assume dietary intake alone is sufficient—very few foods contain meaningful amounts of vitamin D without fortification 4, 5
• Avoid single massive doses (300,000-500,000 IU), as these may be associated with adverse outcomes 3, 6
• Do not supplement without considering total intake—account for any vitamin D already present in multivitamins or fortified foods 2
• Do not use adult osteoporosis dosing (800-1,000 IU) as the standard for healthy adolescents, though this higher dose would still be safe and within tolerable limits 1, 3