Boron as a trace element,shown to increase plasma steroid hormones particularly estradiol and testosterone. Boron supplementation stimulate mitogen activated protein kinases(MAPK) inducing cell proliferation.

Boron appears to have a regulatory role in 26 enzymes and it act as a main role in bone health by increasing calcium absorption.In animal studies dietary boron supplementation reduces prostate tumor size and tumor trophic factor IGF-1.

Boron is rapidly absorbed in the gut and excreted through urine. Common Dose used is 3 mg/dl.Hair can be used for boron deficiency. Hair related products like shampoo contain boron.

Reference

Laboratory evaluation for Integrative and functional medicine by Richard S Lord.