Vitamin D3 25mcg (1,000IU) by Pure Encapsulations

This 1,000 IU capsule suits adults whose Vitamin D (25-hydroxy) level is in range or only slightly low and who want a steady daily dose to keep it there. People who get little midday sun, cover up or use sunscreen consistently, have darker skin, live at northern latitudes or are older commonly run low. If your level is clearly low, one capsule a day is usually too little to bring it up in reasonable time. The label allows up to 5 capsules daily, but settle a repletion dose with your clinician instead of guessing, then step down to maintenance.

Cholecalciferol (vitamin D3) is the form skin makes from sunlight, and it raises blood levels more reliably than vitamin D2. The liver converts it to 25-hydroxyvitamin D, the form measured on a blood test, and the kidneys then make the active hormone. That hormone increases calcium and phosphorus absorption from the gut, which is why vitamin D matters for bone, and it supports normal muscle and immune function.

Each capsule provides 25 mcg (1,000 IU) of vitamin D3. The label's directions are 1–5 capsules daily, consumed with food, or as directed by a health professional. A meal that contains some fat improves absorption; the time of day does not matter. One capsule a day is a common maintenance amount. The label recommends that people taking more than 50 mcg (2,000 IU) of vitamin D a day have their blood levels monitored, so go above 2 capsules only with a Vitamin D (25-hydroxy) result and your clinician's advice.

Vitamin D raises calcium absorption, so people with high blood calcium, primary hyperparathyroidism, sarcoidosis or another granulomatous disease, a history of calcium kidney stones or significant kidney disease should take it only under medical supervision. The top of the label's range, 5 capsules (125 mcg, 5,000 IU), is above the 100 mcg (4,000 IU) a day usually given as the adult upper limit without supervision. Thiazide diuretics add to the risk of high calcium, and high calcium is dangerous with digoxin. Orlistat and bile acid sequestrants reduce absorption. If you are pregnant or nursing, have a health condition or take any medication, check with your clinician first.

Blood levels change slowly. Retest Vitamin D (25-hydroxy) about 3 months after starting or changing a dose; checking sooner mostly shows a level still on the move. You will not feel a capsule working. Compared with higher-strength capsules sold for repletion, this strength leaves room to fine-tune a dose, and compared with drops it is simpler but less flexible. Calcium and PTH Intact are the companion tests when your clinician is looking at bone health.