VitaminWell-studiedMineral

Calcium Citrate

Also known as Calcium

Half-life

Bone turnover: ~10 years

What is Calcium Citrate?

Most bioavailable calcium form — does not require stomach acid for absorption unlike calcium carbonate.

How Calcium Citrate works

Provides elemental calcium for hydroxyapatite crystal formation in bone matrix, muscle contraction (troponin-C binding), and nerve impulse transmission via calcium channels.

Benefits & uses

Bone density support
Muscle/nerve function

Common uses: Bone density, muscle function, nerve transmission, blood pressure regulation.

Longevity

Calcium Citrate dosage

Typical dose: 500 mg per dose (max absorption per dose) taken 2x daily with meals. Total calcium from all sources: 1000–1200 mg/day.

Calcium Citrate half-life

Bone turnover: ~10 years; plasma: rapid equilibration

Calcium Citrate side effects

Constipation at high doses. Interactions with certain antibiotics and thyroid medications.

Constipation with high doses
Kidney stone risk if calcium intake is very high without adequate hydration
Interacts with thyroid medications, bisphosphonates, certain antibiotics — take with gap
Constipation
Bloating

Warnings & monitoring

Pair with K2/D3 so calcium goes to bone; avoid excessive supplemental calcium

Calcium Citrate interactions

with Iron
Caution · mild
Calcium strongly inhibits non-heme iron absorption in the gut. Taking both together can significantly reduce iron bioavailability — particularly important for those treating iron-deficiency anemia.
Timing: Separate calcium and iron supplements by at least 2 hours

Commonly stacked with

Vitamin D3 Vitamin K2 MK-4

Track Calcium Citrate in Protokol.

Log doses, model half-lives, check interactions, and line it all up against your bloodwork. Free on iPhone and Android.