Vitamin D: Why 'Normal' Is Often Not Enough
Vitamin D is where 'technically normal' and 'actually optimal' diverge most often. A value that clears the lab's floor can still leave performance and recovery on the table.
What the number reflects
The 25-hydroxyvitamin D test measures your circulating reserve. Many labs flag anything above ~50 nmol/L as sufficient, but a lot of optimization frameworks target a higher band for bone, immune, and mood benefits.
Deficiency is common in anyone who trains indoors, lives at higher latitudes (most of Canada), or has darker skin.
In enhanced context
- Hard training raises the cost of being under-replete; recovery and immune resilience both lean on adequate vitamin D.
- Supplementation dose and target are worth confirming with a clinician — megadosing is not better and fat-soluble vitamins accumulate.
FAQ
Being inside the reference range means you're not deficient by the lab's definition, but many optimization frameworks aim higher for fuller benefit. The right target depends on you — discuss it with a clinician.
Related: Calcium · Magnesium
Educational information only — not medical advice, diagnosis, or treatment, and not a recommendation about any medication or compound. Reference ranges are context estimates pending clinical review. Consult a physician about your results.