✓ LEGITSupplements
Vitamin D (if deficient)
Correcting deficiency improves energy, mood, and possibly testosterone — foundational, not cosmetic.
Also called: vitamin d3 · d3 supplement · cholecalciferol
Verdict — legit
Does what it claims, with evidence behind it.
Evidence grade B
At least one good randomised trial, or consistent findings across controlled studies.
Mechanism
Steroid pro-hormone involved in hundreds of pathways including endocrine function, muscle protein synthesis, and skin barrier integrity.
Citations
- Vitamin D and human health: lessons from vitamin D receptor null miceEndocrine Reviews · 2008
The full read
This is a health floor, not a looks ceiling: deficiency (very common in northern latitudes) degrades sleep, training output, and mood — all upstream of how you look. Supplementing beyond sufficiency does nothing extra. Test, then dose.
Photo: Bottle of Super-D oil capsules, London, England, 1940-1945 Wellcome L0057855.jpg by Wikimedia Commons · CC BY 4.0 via Wikimedia Commons.
