Protein powders and amino acid supplements deliver different results. Protein powders boost your total protein and contribute calories, so they support muscle building and can fill in gaps in your diet. Amino acids target very specific and diverse areas of your metabolism. One amino acid may affect brain chemicals, while another improves muscle performance. Supplements, including protein powders and specific amino acids, may cause side effects, so talk to your health care provider to be sure they’re safe for you.
Protein powders and amino acid supplements enter your blood stream as single amino acids, then cells throughout your body collect the amino acids needed to build new proteins. If you don’t have enough of one required amino acid, that protein can't be produced. Events that affect your metabolism, such as increased muscle activity or illness, may impact the amount of total protein you need, but one thing stays the same: To ensure that your cells can synthesize vital proteins, you must consume enough of all the essential amino acids every day.
Value of Complete Protein
Protein powders made from milk-derived whey and casein, egg white or soy protein are sources of quality protein that contain all the essential amino acids. Their complete protein supports increased protein demands from athletic activities, and they can contribute to your total daily protein intake. Amino acid supplements do not satisfy daily protein demands and, in large doses, may cause a metabolic imbalance. For example, taking too much leucine, one of the three branched-chain amino acids, may lead to low blood levels of the other two, according to a May 2014 review in the “Journal of the International Society of Sports Nutrition.”
Amino Acid Benefits
In addition to making proteins, some amino acids fill specific roles that directly affect your health outside of protein metabolism. One example is tryptophan, which turns into the mood-regulating neurotransmitter serotonin. Taking supplements may enhance the physiological function filled by these amino acids. Supplemental creatine increases muscle strength and improves performance in high-intensity, short-duration exercise, reports Iowa State University Extension and Outreach. Branched-chain amino acids may help promote muscle protein synthesis, according to the May 2014 review in the "Journal of the International Society of Sports Nutrition.”
Amino acid supplements contain minimal calories, but one scoop of protein powder has about 120 calories, and some brands may have significantly more. Be sure these extra calories don't exceed your daily goals. Soy naturally contains isoflavones, which exert an estrogen-like effect. Avoid soy-based protein powders if you have thyroid disease, a history of breast or uterine cancer, or you're pregnant, recommends NYU Langone Medical Center. Most amino acids are safe, but some may cause side effects, such as muscle cramps or gastrointestinal problems, and others should be avoided if you have heart or kidney disease, so it’s especially important to consult your physician before taking supplements.
- Bellevue College: Protein
- Journal of the International Society of Sports Nutrition: Evidence-based Recommendations for Natural Bodybuilding Contest Preparation: Nutrition and Supplementation
- Journal of the International Society of Sports Nutrition: International Society of Sports Nutrition Position Stand: Protein and Exercise
- Iowa State University Extension and Outreach: Supplements
- Huntington College of Health Sciences: Amino Acids
- NYU Langone Medical Center: Isoflavones
- MedlinePlus: L-Arginine
- The Journal of Nutrition: The Nature of Human Hazards Associated with Excessive Intake of Amino Acids
- MedlinePlus: Tryptophan