What Are the Mental Side Effects of Creatine?

Creatine is a compound that is synthesized in your body by your pancreas and used for energy production in your skeletal muscles, with 95 percent of creatine stored in your muscles and the remaining 5 percent in your brain. Creatine can also be ingested as a nutritional supplement and ergogenic aid designed to increase exercise performance, principally muscle power and strength. Creatine is a well-studied compound; however, its effects on your brain and mental state are less understood.

Man looking out window. (Image: ColorBlind Images/Blend Images/Getty Images)

Creatine and the Brain

Creatine readily crosses the blood-brain barrier, a protective barrier around your brain that is designed to keep out harmful chemicals and toxins. Once inside the brain, a creatine molecule binds with a phosphate molecule making the compound creatine phosphate, or CP. CP is an energized form of creatine that may increase the energy consumption of your brain. The presence of CP in your brain may improve cognition and memory but may have some side effects as well, according to "Physiology of Sport and Exercise" by Jack H. Wilmore et al.

Neurotransmitter Function

Creatine may affect the production of brain neurotransmitters, which are hormone-like chemical compounds produced in your brain that have both neurological and hormonal effects on your body. Dopamine is a neurotransmitter that is responsible for feelings associated with motivation and pleasure, and may be affected by the presence of CP in your brain. Lowered levels of dopamine may increase the symptoms associated with depression, psychosis, and schizophrenia. Creatine supplementation is not recommended if you suffer from any of these conditions.

Creatine and Serotonin

Although not conclusive, creatine may affect the production of serotonin, which is a compound produced in your brain that is primarily found in your intestinal tract, blood platelets, and throughout your central nervous system, according to "Journal of Hyperplasia Research." Serotonin has many functions, including the regulation of mood, appetite, sleep, memory and learning. When excessive amounts of creatine is present in your brain, serotonin production may be suppressed, increasing the risk of developing some of the symptoms associated with low serotonin levels, such as weight gain, reduced insulin secretion, depression and diminished learning.

Creatine and Dehydration

A well-known effect of creatine supplementation is muscle hydration, which involves the retention of body water in your skeletal muscles along with creatine. Muscle hydration may leave less water available for the rest of your body's cells to function optimally, causing a state of dehydration. Dehydration, or a lack of water, can affect your brain by reducing blood flow and oxygen delivery to brain cells. This may cause you to feel faint or lightheaded and can increase your risk of developing acute anxiety, nervousness and confusion.