You need UVB rays, not just sunshine Only UVB radiation triggers vitamin D production in the skin. Many things block UVB: Clouds, air, pollution, sunscreen, makeup, clothing, etc. Vitamin D starts as cholesterol If cholesterol is: • Too low • Suppressed by statins • Poorly produced due to hormonal or metabolic issues Skin tone and aging matter • Darker skin (more melanin) naturally blocks UVB • Aging skin produces up to 75% less vitamin D than younger skin Your liver and kidneys must activate it

UVA vs. UVB Radiation - What You Need to Know