L-Histidine is an essential amino acid that produces histamine, which aides with allergy systems.

L-Isoleucine is an essential alpha-amino acid that is considered both, a ketogenic and a glucogenic amino acid. Since that L-Isoleucine is an essential amino acid, it cannot be synthesized by the body, therefore it needs to be ingested. The primary source of L-Isoleucine is as a component of proteins. It has become a prominent component of nutritional supplements, mostly with the body building and similar athletic communities, where it is believed that L-Isoleucine has the capability to increase endurance, but also to repair muscle tissue. It has been observed that L-Isoleucine ingestion allows power athletes to recover easier from very tough trainings and exhausting activities. This branched chain amino acid is one of the three main BCAA in the body, the other ones being valine and leucine.

L-Leucine with the food additive E number code E641 is classified as a flavor enhancer. Leucine is actually an essential alpha-amino acid and a vital part of so called “buffer” proteins, such as ferritin and astacin. You can find leucine in foods such as whole wheat bread products, nuts and brown rice. As a supplement, researchers have found that leucine slows the degradation of muscles and muscle tissues through an inflated synthesis of muscle proteins. In the human body, leucine can be found in the liver, but most prominently in the muscle and adipose tissues, where it is utilized in production of sterols. In body building circles L-Leucine as a dietary supplement is very popular for all these properties, but also for the preservation of muscle glycogen, nitrogen balance maintenance and more.

L-Lysine- Lysine is an essential alpha amino acid that needs to be ingested and cannot be synthesized by the human body. Sources of L-Lysine include meat, particularly red meat, lamb, poultry and pork, but also cheeses, like parmesan, some fish like cod and sardines and eggs. Several plants are rich in L-Lysine, soybean, lentil, spinach and buckwheat, but also buffalo gourd, watercress, locust bean and many other bean variants, including the common bean. L-Lysine is deemed vital for the overall production of protein, as a structural building block. It seems that L-Lysine also plays a prominent part in the absorption of calcium. Further properties include playing a role in the production of enzymes, hormones and antibodies, but also in the recovery from sports injuries and surgeries.

L-Methionine is an essential amino acid, actually an alpha amino acid, furthermore classified as nonpolar. This proteinogenic amino acid is the only one, besides cysteine, which contains sulfur. Methionine serves as an intermediate of phospholipids, such as phosphatidylcholine, but also lecithin, taurine, carnitine and cysteine. If methionine cannot be properly synthesized, the condition can lead to atherosclerosis. While it must be supplied with diet, this amino acid is deemed a powerful antioxidant, believed to be a scavenger of free radicals, and may assist with the breakdown of fats. Sources of L-Methionine include poultry and related products, including eggs, but also other meats, such as beef, cheese and fish. Methionine adenosyltransferase is converting methionine to S-adenosylmethionine, SAM, which in turn is involved in the creation of creatine, epinephrine, melatonin and further substances.

L-Phenylalanine gained notoriety with the aspartame controversy where extensive internet bombardment against the artificial sweetener prompted a thorough cleaning by The Coca Cola Company and other interest groups. Now it seems that aspartame has more benefits to health than aspirin. L-Phenylalanine is an essential alpha amino acid that is deemed analgesic and antidepressant. It is hydrophobic and nonpolar, one of only twenty common amino acids that are used to produce protein as coded by the DNA. L-Phenylalanine can also convert into L-Tyrosine, which can then become L-DOPA, going forth to become norepinephrine, dopamine or epinephrine. Phenylalanine is very often found in foods, protein rich foods like meat, milk and milk products, poultry and fish, but also as already mentioned in the artificial sweetener aspartame.

L-Threonine is an essential alpha amino acid, classified as polar. There are three proteinogenic amino acids that have an alcohol group, besides threonine there are tyrosine and serine. Like many other amino acids that are not synthesized in humans, threonine needs to be ingested through protein food sources that contain it, namely meat, poultry, cottage cheese, fish, sesame seeds and others. When ingested, threonine goes either through the threonine dehydrogenase and becomes pyruvate or, as in humans, it can be converted by the enzyme serine dehydratase to alpha ketobutyrate and continue towards succinyl-CoA. Threonine is also supposed to assist the protein balance by maintaining normal growth, but in addition to that, it seems to support the immune system, the central nervous system, the liver and the cardiovascular system.

L-Valine, an essential amino acid, promotes the smooth functioning of the body. It is derived from animal and vegetable proteins like seafood, poultry, meat, cottage cheese, sesame seeds, dry whole lentils and roasted peanuts. It regulates the immune system, assists protein synthesis and glucose metabolism. It also promotes growth of muscles and repair of tissues that get damaged due to stress, disease, surgery or injury. It maintains the body’s nitrogen level and energizes the muscles. L-Valine helps detoxify the body against ammonia and prevents muscle wasting in diabetics. It assists in correcting drug addiction related amino acid deficiencies, gallbladder and liver diseases and is linked with treating neurological conditions and brain damage due to alcohol intake. One should consult a physician before consuming the supplement.