Possible side effects of Vitamin D

It’s very unusual to get any side effects from Vitamin D3 unless too much is taken. However, possible side effects may include: headache, loss of appetite, dry mouth, thirst, frequent urination, constipation, nausea, vomiting, metallic taste, sleepiness, fatigue and weakness.

Taking Vitamin D3 can cause blood calcium levels to rise, and taking a very large daily dose for a long period of time could cause an excess of calcium in the blood. The dose used in PROVENT (4000IU) is large, since our aim is to trigger a beneficial response, but within recommended levels. However, as a precaution, all participants will be tested to make sure their calcium levels are normal before and during the study. Levels are checked via a blood test. Vitamin D3 should be taken with caution by anyone who suffers from kidney or liver disease, as these can also increase blood calcium levels.

Allergic reactions are always possible with any medication. If you experience a rash, itching, dizziness, swelling or difficulty breathing, seek medical advice immediately.


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