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.
The only proven benefit of vitamin D is its role in helping calcium build strong bones. But that's far from the whole story. Vitamin D helps regulate the immune system and the neuromuscular system. Vitamin D also plays major roles in the life cycle of human cells. Vitamin D is so important that your body makes it by itself -- but only after skin exposure to sufficient sunlight. This is a problem for people in northern climates.