Using lye hair relaxers is a popular treatment that straightens coarse or kinky hair. But before you head to the salon for your bi-monthly touch-up, consider what that lye is doing to your hair. Lye, also known as sodium hydroxide, is an especially potent chemical that can be deadly if ingested, warns Drugs.com. If it is so detrimental to your body, think of the damage it could be inflicting on your hair.

When applied to the skin, lye can cause burns and irritation, says the U.S. Food and Drug Administration. If you decide to use a lye hair relaxer, go to a professional, and make sure that your hairstylist applies the lye away from your scalp. Burning of the scalp could result in redness, burning, itching and rash. No-lye hair relaxers exist, and can reduce the amount of scalp damage, but they may not work as well.

Lye effectively strips your hair of amino acids and moisture, found a study by the Groote Schuur Hospital, University of Cape Town, published in the March 2010 issue of "Journal of the American Academy of Dermatology." This is especially detrimental for those who already suffer from dry hair, which kinky and course hair tend to be. The relaxing process usually takes at least 30 minutes, which means the chemical is sitting on your hair for that long. After washing out the relaxing solution, you may need deep conditioning, hot oil treatments, and hair masks to replenish moisture.

Hair is essentially a dead protein, notes the American Hair Loss Association. Damaged hair lacks the active cells to repair itself. Unfortunately, lye hair relaxers strip the hair of moisture, and can burn or break the hair shaft. Once this damage occurs, cut off that hair. KidsHealth.org warns against using lye hair relaxers more often than every six weeks, and points out that heated styling tools can exacerbate the damage.