Vitamin B6 (pyridoxine) has been used as a supplement to reduce prolactin levels. A trial of 60 women of reproductive age showed that 300 mg of vitamin B6 taken in 3 separate doses daily reduced prolactin similarly to cabergoline.[1]
Vitamin B6 has also been suggested as a treatment for hyperprolactinemia caused by antipsychotic medications (like risperidone or haloperidol) and may effectively reduce prolactin levels and improve symptoms of hyperprolactinemia in people who take these medications.[2][3]
Low vitamin D levels are more common in women with hyperprolactinemia and prolactinoma (a prolactin-producing tumor) than in women without hyperprolactinemia. This association might not be causal; however, a low vitamin D level combined with an elevated prolactin level can lead to a decrease in bone density, especially in postmenopausal women.[4][5] With this in mind, a vitamin D supplement is useful in certain patients with hyperprolactinemia. It is best to check the vitamin D level before starting supplementation.