Peppermint, a source of small amounts of menthol, is believed to work by acting on receptors in the nasal mucous membranes, leading to a reduction of nasal stuffiness. Eucalyptus oil is often used in a steam inhalation to help clear nasal and sinus congestion.
Vitamin D is essential for maintenance of bone mineralization through the regulation of calcium and phosphorus homeostasis. Vitamin D also exhibits many non-skeletal effects, particularly on the immune, endocrine, and cardiovascular systems.
Newer methods, however, may report levels of both D 2 and D 3 and then add them together for a total level. The main role of vitamin D is to help regulate blood levels of calcium, phosphorus, and (to a lesser extent) magnesium.