Nutritional supplements have many important health benefits, including improving hair quality, but when taken in excess they may cause hair loss. Here is a rundown of the supplements that could have this effect and the proper recommended dosage of each.
Vitamin A is important for eye health, immunity and maintaining hair, skin, teeth and bones, but exceeding 25,000 IU per day could become toxic and lead to a condition known as hypervitaminosis. This condition causes temporary hair loss and other medical conditions, especially in women. The safe dosage of vitamin A is 4,000 to 5,000 IU per day.
Excessive zinc consumption produces hair loss because it interferes with the body's ability to absorb copper, iron, magnesium and manganese, all of which are essential for healthy hair. Zinc can become toxic when taken in excess of 60 milligrams daily. Stick closer to the recommended daily dose of 11 milligrams, though increased dosages under 60 milligrams may increase hair growth.
Hormones typically found in birth control pills and hormone replacement therapy (HRT) have been proven to speed hair growth, though faster hair growth means your hair reaches its resting phase and falls out more rapidly than normal. As a result, people who take birth control or HRT medicines may experience hair loss. Ordinarily, the body adjusts to the hormones after three to four months and hair loss subsides.
Prescription medication, alcohol and recreational drugs alter the way supplements are absorbed and may require you to take different dosages. Likewise, pregnant and nursing women need slightly higher dosages of vitamins and minerals than normal, and women who have just given birth may need to adjust their dosages as well. If any of these conditions apply to you, ask a doctor or nutritionist before taking supplements.
The content of dietary supplements is not analyzed by the U.S. Federal Drug Administration, so you can never be 100 percent certain the supplement you've purchased actually is what the label claims it to be. Fortunately, some companies voluntarily follow the standards that the FDA establishes for medicine. Research vitamin producers before buying supplements so you can be sure yours come from a reliable source.