The hyponatremia is caused by a relatively smaller loss in total body water. 1  any cause of hypovolemia such as prolonged vomiting, decreased oral intake, severe diarrhea. 2  diuretic use (due to the diuretic causing a volume depleted state and thence ADH release, and not a direct result of diuretic-induced urine sodium loss)
Biotin is safe but is not likely to do much to help your hair grow unless you are deficient in biotin, which is uncommon. A reasonable dose is 5 mg. However, you may get better results by taking a quality multivitamin, eating a healthy diet rich in organic fruits and vegetables, avoid junk food and getting adequate sleep.
In people without disorders of biotin metabolism, doses of up to 5 mg/day for two years were not associated with adverse effects (52). Oral biotin supplementation has been well tolerated in doses up to 200 mg/day (nearly 7,000 times the AI) in people with hereditary disorders of biotin metabolism (1).