Can too much vitamin d give you hot flashes and night sweats?

No: Vitamin d regulates your body's absorption of calcium, so too much vitamin d will lead to hypercalcemia or too much calcium in your blood. Hypercalcemia typically manifests as constipation, nausea, polyuria (excess urination), and in severe/chronic cases, renal problems and cardiovascular issues. None of these issues would manifest as hot flashes or night sweats.

No: Excessive doses of some b vitamins (niacin) can cause what is called flushing which can cause night sweats and hot flashes.