If you're looking to build muscle, understand that alcohol consumption can hinder your results in multiple ways. In addition to directly reducing muscle protein synthesis, alcohol can interfere with hormones that are necessary for building muscle. Furthermore, alcohol can decrease important molecules and nutrients that supply the energy required for muscle-building workouts.
Reduces Protein Synthesis
According to the University of Notre Dame Office Office of Alcohol and Drug Education, drinking alcohol can cancel out any potential physical gains you could acquire from training. Both short-term and long-term alcohol consumption can reduce protein synthesis -- or muscle growth. A study published in 2001 in "Alcoholism, Clinical and Experimental Research" found that in a test-tube study, alcohol caused a significant 15 percent to 20 percent decrease in baseline protein synthesis after a 24-hour period.
Because alcohol can interfere with sleep, it can keep your body from repairing itself after a workout. During sleep, an important chemical known as human growth hormone is released, which triggers muscle growth. According to Notre Dame, alcohol can reduce human growth hormone levels by as much as 70 percent. Testosterone is another hormone that is important for muscle growth and development. When alcohol is present in the body, however, it can prompt the manufacture of a substance in the liver that is toxic to testosterone, notes Notre Dame.
UCSD Student Health Services notes that once alcohol makes its way into your cells, it can cause water imbalances in muscle cells, which can lead to reduced adenosine triphosphate -- a molecule required by your muscles for energy. Therefore, in addition to directly inhibiting muscle protein synthesis, alcohol can limit muscle energy, which can lead to decreased exercise performance and reduced muscle adaptation.
Inhibits Vitamin Absorption
Vitamins and minerals are required for the proper growth and development of human cells. Alcohol use can interfere with the absorption of certain nutrients. UCSD Student Health Services notes that drinking alcohol can inhibit the absorption of three B vitamins -- thiamine, vitamin B-12 and folic acid -- as well as the mineral zinc. B vitamins and zinc are essential to supplying the body with energy, which also makes them necessary for completing muscle-building workouts.