Are You Fully Knowledgeable About Cysteine?

Cysteine, also known as α-aminothio-β-propionic acid, is a chemical compound belonging to a category of 22 basic, branched-chain amino acids. Cysteine is an endogenous substance that should be included in the list of substances necessary for the proper functioning of our bodies. A key aspect is the presence of a thiol group responsible for the formation of disulfide bridges that affect the tertiary structure of proteins. Together with homocysteine and methionine, it forms a group of sulfur-containing amino acids. Cysteine is produced by the transfer of a sulfur atom from the methionine molecule to serine using adenosine triphosphate (ATP).

Cysteine is considered a member of the group of reactive amino acids, which means that it has a significant influence on the detoxification and regenerative processes of the human body. One of the basic functions of α-amino-β-thiolopropionic acid is its role in the synthesis of glutathione, one of the strongest and most effective antioxidants. In cooperation with glycine and glutamine, it is also an important component of the basic antioxidant content in our body. It is also worth mentioning that cysteine has a strong effect on skin cleansing, and that N-acetyl-L-cysteine, a metabolite of cysteine, is used in cases of alcohol poisoning, heavy metal poisoning (such as cadmium, mercury, lead), and drug poisoning, and also effectively supports liver regeneration. In addition, cysteine participates in a series of reactions leading to the formation of new protein and coenzyme molecules. For example, the processes of decarboxylation and oxidation of cysteine result in the production of taurine molecules, which increase energy and facilitate the transport of creatine. In addition, cysteine is responsible for the production of chondroitin sulfate, a component of proper connective tissue and cartilage tissue. Therefore, it can be said that cysteine affects the condition of our skin, hair, and nails. The antioxidative character of cysteine also has a prohealthy effect on the cardiovascular system. Cysteine-containing preparations are often recommended for protection and strengthening the functionality of the heart and the entire vascular system. The strong effect on the walls of arteries and veins is also used in the treatment of arteriosclerosis. Furthermore, cysteine-containing agents are often recommended for cancer, rheumatoid arthritis, and respiratory problems such as tuberculosis or bronchitis.

Cysteine predominantly resides in the protein structures found in the fundamental fibers – the previously mentioned skin, hair, and nails. A deficiency of cysteine, being one of the components for the synthesis of chondroitinosulfuric acid, will primarily manifest as a weakening of the resilience of these structures. This can result in easily breakable and brittle hair, accelerated degeneration and greater brittleness of the nail plate, as well as difficulties with keratinization of the skin. It is recommended that daily supplementation of cysteine should range from 50 to 500 mg of the substance. It is typically suggested to take it in conjunction with vitamin C, which should be consumed in a ratio of 1:3. This refers specifically to a dose of 50 mg cysteine and 150 mg ascorbic acid. Individuals suffering from diabetes should be particularly cautious during cysteine treatments, as the medication can inhibit the action of insulin – treatment should be discussed with a doctor.

Cysteine, being an amino acid, cannot be found on the market of dietary supplements as a standalone product. This compound often appears in various amino acid matrices such as BCAA, EAA or SAA. In most cases, these are supplements focused on enhancing regenerative and purifying processes, as well as contributing to the increase in the intensity of anabolic transformations. Cysteine is also a common ingredient in skin and hair cosmetics that contain 1% and 4% of this amino acid respectively. When it comes to natural sources of amino acids, one should primarily pay attention to high-protein products. Beef and poultry, as well as plants with a high protein content such as beans, lentils, soy, spirulina, contain the largest amounts of amino acid. A high amount of cysteine has also been noted in the structure of milk proteins, namely casein.