Vitamin D is a fat-soluble vitamin. Very few foods naturally contain vitamin D.
50 Shades of Gray: Depression Common in Borderline Testosterone
Serum total testosterone concentrations fall with increasing age, and free testosterone concentrations fall even more. This fall might have adverse consequences on energy, sexual function, muscle mass and function, erythropoiesis, and bone. Some of the decline in testosterone is related to the development of obesity and other comorbidities such as diabetes mellitus; evaluation and management of these comorbidities is therefore essential.
The association between low levels of 25-hydroxyvitamin D and non-specific musculoskeletal pain, including fibromyalgia syndrome, is controversial. Several studies have reported a “positive association” and two others found “no association.”