Deficiency and toxicity: As with other B vitamins, there are no specific toxic effects from high doses of pantothenic acid. Over 1,000 mg. daily has been taken for over six months with no side effects; when 1,500 mg. or more is taken daily for several weeks, some people experience a superficial sensitivity in their teeth. However, it is possible that if B5 is taken without other B vitamins, it may create metabolic imbalance.

Fatigue is probably the earliest and most common symptom of pantothenic acid deficiency, though it is an unlikely vitamin deficiency because of the availability of B5 in many foods, plus the fact that it is also produced by our intestinal bacteria. A diet high in refined and processed foods or a reduction or destruction of intestinal flora, most commonly by antibiotic use, can lead to a vitamin B5 deficiency. Teenagers are more likely to experience a deficiency, because their diets often include high amounts of "fast foods" sugars, and refined flours (all low in B vitamins). And the problem may be compounded because the acne often associated with this type of diet is commonly treated with tetracycline antibiotics, which reduce the intestinal bacteria and thereby the production of pantothenic acid in the colon.

Studies of pantothenic acid deficiency in rats showed increased graying of the fur, decreased growth, and, in the extreme, hemorrhage and destruction of the adrenal glands. In humans, the decreased adrenal function caused by B5 deficiency can lead to a variety of metabolic problems. Fatigue is most likely; there may also be physical and mental depression, a decrease in hydrochloric acid production and other digestive symptoms, some loss of nerve function, and problems in blood sugar metabolism, with symptoms of hypoglycemia (low blood sugar) being the most common. Pantothenic acid affects the function of cells in all systems, and a deficiency may reduce immunity, both cellular and antibody responses. Other symptoms of B5 deficiency include vomiting, abdominal cramps, skin problems, tachycardia, insomnia, tingling of the hands and feet, muscle cramps, recurrent upper respiratory infections, and worsening of allergy symptoms.

Requirements: The RDA for pantothenic acid is about 5 mg. for children and 10 mg. for adults. Many other sources feel the minimum needs are more likely to be about 25–50 mg., and 50–100 mg. is probably a good "insurance" range. Therapeutic ranges are more like 250–500 mg. daily and even higher, taken, of course, along with the other B complex vitamins. Individual needs vary according to food intake, degree of stress, and whether one is pregnant or lactating. Those people who eat a diet of processed foods, have a stressful lifestyle, or have allergies require higher amounts of pantothenic acid. For all of the problems discussed here, 250–500 mg. taken twice daily is a safe and beneficial amount.