Cancer-Causing Chemicals in Hair Straighteners

This is only a partial list of some of the cancer-causing chemicals and substances that have been found in chemical hair straighteners and relaxers. These chemicals are known as endocrine-disrupting chemicals, because they disturb the functions of the endocrine system, which regulates the body’s production of hormones.

What is the Endocrine System?

The endocrine system regulates the body’s production of hormones, which are the body’s chemical messengers. Glands in our bodies secrete hormones into the bloodstream. The major endocrine glands are the adrenal glands, the pancreas, and the pineal, pituitary, thymus, and thyroid glands. People also produce hormones in their ovaries or testes.

Hormones work slowly and affect many different bodily processes and aspects, including:

• Mood
• Metabolism (the process by which the body changes food and drink into energy)
• Reproduction
• Sexual function

Hormones are powerful. A small amount of hormones can effect big changes in individual cells or even throughout the body. That is why too much or too little of a hormone can cause serious problems.

What Do Endocrine-Disrupting Chemicals Do?

Endocrine-disrupting chemicals (EDCs) disturb the functions of the endocrine system. EDCs are chemicals or chemical mixtures that interfere with the way hormones work.

• Some EDCs mimic the body’s natural hormones—they “trick” the body into thinking they are hormones, so the body responds accordingly.
• Some EDCs may block natural hormones from doing their jobs.
• Other endocrine-disrupting chemicals can increase or decrease the amount of hormones in a person’s blood by affecting how the hormones are made, broken down, or stored in the body.
• Still other EDCs change the body’s sensitivity to different hormones.

Even low amounts of EDCs may be unsafe. As noted, the body’s normal endocrine functioning involves very small changes in hormone levels causing significant biological and developmental effects. Disruptions to the endocrine system and to the body’s hormone levels can have serious consequences. Exposure to EDCs has been linked to numerous adverse health outcomes, including certain types of cancer.

People may be exposed to endocrine-disrupting chemicals through the air they breathe, food they eat, and water they drink. EDCs can also enter the body through the skin, such as when hair straightening chemicals containing EDCs are applied to a person’s scalp.