L-cysteine ​​– what is it, formula, instructions for use

Cysteine is an amino acid that is divided into two types, L- and D-isomers. These chemical compounds are identical in composition and molecular weight, but differ in the structure of their atoms. Their chemical and physical properties differ insignificantly. In this article we will discuss L cysteine.

L cysteine is one of the so-called conditionally essential proteins. This substance can be synthesized independently in the body, but in some cases it needs to be replenished from the outside.

Essential sulfur-containing amino acid for healthy skin, hair and nails. Stabilizes protein structure and promotes collagen production.

Instructions for use of L cysteine depend on the purpose. Additionally, taking an amino acid may be necessary during intense physical activity in sports, during stress, as well as for medical and cosmetic purposes.

Let's take a closer look at what L cysteine is and what its beneficial properties are for humans. Also, before using drugs with L cysteine, you should carefully read the instructions for use and read reviews.

general information

Cysteine (Cys) is a representative of non-essential sulfur-containing amino acids. The substance is part of the proteins of all tissues of the human body. Its formula was discovered at the end of the 19th century by the scientist Bauman, and the properties were studied in detail by Merner. These researchers obtained cysteine from animal horns. But for the production of dietary supplements, synthetic forms of amino acids or natural proteins obtained after processing keratin-containing waste are used.

Cysteine and cystine are not the same thing! The second will be created during the chemical transformation of the first with the formation of disulfide bonds between the two molecules.

Application in the food industry

In the composition of some products and products you can see the E920 additive - this is the amino acid in question. In the international classification it belongs to the category of permitted. In particular, this additive is used in bread production. It significantly improves the properties of the dough (giving elasticity) and the finished product (reducing the likelihood of cracks and voids). Also, under the influence of cysteine, the time for rising dough is reduced and the amount of the final product increases.

The substance is actively used in the production of meat products in combination with dyes. The amino acid significantly speeds up the process of coloring the product, and also ensures color preservation during storage and heat treatment. In addition to these properties, E920 significantly enhances the taste properties of sausages.

Chemical properties

Photo - Structural formula of cysteine
The international chemical name of the substance is 2-amino-3-mercaptopropanoic acid. The amino acid has 2 optical isomers - L and D (only the L-form is used in medicine), as well as 1 sulfur atom. In its pure form, the substance is a colorless crystalline powder that quickly dissolves in water and interacts with acids and alkalis. When heated, it can be converted to cystine.

How quickly does the effect of taking cysteine appear?

L-cysteine is an easily absorbed amino acid by the body. It is easily absorbed by the stomach when taken orally, after which cysteine biochemically breaks down into various derivatives: taurine, glutathione, chondroitinsulfuric acid and some other substances. For these processes to occur, cysteine is oxidized in the body. The benefits of taking the amino acid have been clinically proven, and the effect begins immediately after it enters the stomach. The appearance of the effect of the intake is accelerated by additional consumption of selenium and vitamin C.

Biological role

The nonessential amino acid compound cysteine is synthesized in the body with the participation of methionine, serine, and pyridoxine (vitamin B6). The formation of a sulfur-containing amino acid requires the presence of hydrogen sulfide. Normally, nutrient synthesis completely covers the needs of an adult. In case of liver diseases, metabolic disorders, active physical activity, the amount of the substance decreases.

Under the influence of cysteine, 2 important compounds are synthesized:

Glutathione. It is a powerful natural antioxidant, protects cells from free radicals, and slows down the aging process. The substance is necessary for the proper functioning of cellular immunity.
Taurine. Helps with the functioning of the cardiovascular, nervous and endocrine systems. Supports visual function and participates in metabolic reactions.

L-cysteine also produces a number of beneficial effects:

improves muscle tone and strength, elasticity of the vascular wall, as well as the condition of the skin, nails, and hair structure;
reduces the risk of cardiovascular crises, the activity of inflammatory processes;
promotes muscle growth, detoxification of the body from heavy metal salts and other harmful substances;
increases endurance and energy, as well as blood supply and trophism of the eye lens;
participates in the synthesis of building proteins, collagen and elastin;
activates metabolic processes, helps burn excess fat;
normalizes immune reactions.

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Its effect on the human body

The benefits of L-cysteine for our health are difficult to overestimate. The first signs of a lack of this substance are displayed directly externally. Deterioration of the skin and hair, brittle nails and rapid aging - all this may indicate an amino acid deficiency. Problems in internal systems are less noticeable, but can still lead to serious consequences.

What is the danger of cysteine deficiency?

Increased fragility of hair and nails.
Premature skin aging.
Decreased vitality, loss of strength.
Physical exhaustion of the body, slowing down regeneration processes.
Depressed state, depression and constant fatigue.

Cysteine is a natural antioxidant that allows you to quickly remove harmful substances from the body. It even gets rid of heavy metals and radioactive damage, so it is extremely important for residents of contaminated areas to regularly undergo such a course of intoxication.

Cysteine requirement

For an adult, the daily norm is 1-2 g per day. This amount includes cysteine from natural sources and an amino acid synthesized in the body. It is recommended that pregnant and lactating women consume this substance in consultation with their doctor. But there are no standards set for children.

But first it is recommended to find out the level of the substance in the body. To determine the concentration, you can use a comprehensive blood test for amino acids. If cysteine metabolism is suspected, additional testing of amino acids and taurine is usually prescribed.

L-cysteine for hair

This amino acid is most beneficial for beauty. A lack of cysteine can lead to brittle nails and hair, while sufficient consumption of it significantly improves their condition. In addition, L-cysteine ensures a thickening of the protective layer of the hair shaft, providing additional volume and strength to weakened strands. All this is possible due to the identical composition of amino acid molecules with the structure of hair, as well as stimulating the production of collagen protein in the body naturally.

Amino acid in food

Table - Main food sources of cysteine

Product name	Amount of L-cysteine, mg per 100 g
Soybeans	655
Sunflower seeds	451
Peas	373
Coarse wheat flour	317
Eggs	272
Chicken meat	222
Red fish fillet	219
Walnuts	208
Brown rice	96

Although the amino acid cysteine is found in many foods, it tends to be destroyed when cooked. The aggressive environment in the stomach and special microflora also interfere with the absorption of the substance. Therefore, it is impossible to obtain the daily requirement of cysteine from food.

For hair and skin

L-cysteine is a component of keratin, the protein that makes up our skin, hair and nails. A lack of amino acids can have a detrimental effect on their condition and appearance. Taking medications containing this amino acid will strengthen your hair, make it less brittle, and give it a beautiful and healthy appearance.

The use of cysteine will help restore and strengthen hair after perm, coloring and other negative effects of chemicals. The transformation of your skin will also not go unnoticed - it will become firmer and more elastic, dryness will decrease, and wrinkles will be reduced. As a result, you will experience a significant skin rejuvenation effect.

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Indications for use

Amino acid-based drugs are used to prevent and treat a number of diseases:

poisoning with pesticides, chemicals, heavy metals;
cataracts, retinopathy and other diseases of the visual organs;
arthritis, arthrosis, osteochondrosis;
ischemia of the lower extremities, atherosclerosis;
gastrointestinal diseases - gastritis, gastric or duodenal ulcers;
chronic bronchitis, emphysema, respiratory failure;
burns, frostbite.

It is also recommended for older people to take amino acid-based dietary supplements to stimulate regenerative processes, reduce the effect of free radicals, and increase vigor and energy. The substance is also prescribed to minimize the side effects of radiation or chemotherapy.

Interesting! The supplement is actively used in sports to improve training performance, gain muscle mass, and accelerate body recovery after physical activity.

Use in complex treatment

L-Cysteine is not just a general strengthening substance. This is a powerful auxiliary tool that is actively used in the complex treatment of many diseases. Here are the most common uses of this amino acid:

therapy for bronchitis and enphysema (destroys and promotes the removal of pathogenic mucus from the respiratory tract);
minimizing the effects of chemotherapy and radiation;
accelerating recovery after any illness (by stimulating the production of lymphocytes and leukocytes);
cleansing the body in case of poisoning with lead, aldehydes and pesticides;
treatment of ophthalmological diseases (in particular, cataracts);
fight against arthritis and arthrosis (due to powerful anti-inflammatory effects);
tissue restoration after burns and frostbite;
maintaining the functioning of the cardiovascular system during treatment of pathologies;
treatment of colitis and other cases of intestinal inflammation;
fight against alcohol intoxication (due to powerful antioxidant effects).

Dosage forms

For the production of dietary supplements, a natural compound or its synthetic analogue is used. In medicine, chemical forms of the amino acid are used: acetylcysteine (ACC), cysteine hydrochloride, N-acetyl-B-cysteine, acestine. Most drugs contain a standard concentration of a chemical compound - 500 mg in 1 capsule/tablet.

general characteristics

In the human body, cysteine is used to produce taurine and glutathione. Taurine is important as a substance that plays a key role for the adequate functioning of the central nervous system. It also helps control blood pressure, maintains eye health, helps build muscle and burn excess fat.

Glutathione is essential for the functioning of the immune system, as it is a powerful antioxidant and also protects the nervous system from damage. By the way, researchers are increasingly linking early aging and loss of strength to glutathione deficiency. At the same time, it has already been proven that the consumption of dietary supplements is not able to restore the required level of glutathione in the body. Maintaining adequate concentration of the substance is possible only in the presence of cysteine.

Cysteine, a substance with the formula C3H7NO2S, in turn, is necessary for maintaining glutathione concentrations, as well as for the functioning of muscle tissue. This amino acid plays an important role in the production of T cells (lymphocytes) and strengthening the immune system. This substance is also a component of human hair. And as experiments have shown, this element is capable of increasing the diameter of hairs. In addition, it is part of insulin, and, if necessary, can be converted into glucose, thus saturating the body with additional energy.

The beneficial effects of cysteine are also felt by the gastrointestinal tract. Since some medications (for example, aspirin) damage the gastric mucosa, this useful component protects the organ cavity and restores the mucous layer.

Rules for the use of dietary supplements

According to the instructions for use, the initial therapeutic dosage of cysteine in an adult is 500-1500 mg per day. For athletes and bodybuilders, the norm reaches 2500-3000 mg. The maximum dose of cysteine is 7 g.

Supplements should be taken with food or 1-1.5 hours after eating. During the period of use of medications, you need to increase fluid intake to 1.5-2 liters per day. The course of treatment lasts on average 1-2 months.

Watch a video about what vitamins can be taken along with cysteine to speed up hair growth and improve hair condition:

Manifestations of oversaturation and deficiency

An increased content of amino acids in the human body almost always leads to allergies. Along with them - irritability, intestinal dysfunction and blood thickening.

AK deficiency manifests itself in the unsatisfactory condition of nails, skin and hair. The mucous membranes rapidly lose moisture and cracks form. Suffering from depression. Moreover, a lack of cysteine provokes vascular diseases, digestive system failures, decreased immunity, and decreased brain activity.

Possibility of overdose

An excess of the substance in the body is most often observed when the instructions for the drugs are not followed and the therapeutic dose is significantly exceeded. Symptoms of overdose can also occur during treatment with dietary supplements and the constant presence in the diet of foods high in cysteine (eggs, bran bread, cereals).

Signs of excess amino acid in the body:

nausea and vomiting;
diarrhea;
stomach ache;
breathing problems;
arrhythmia;
severe headaches.

If such symptoms appear, you should stop using the medication and seek medical help. The doctor will determine the severity of the condition and, if necessary, conduct detoxification therapy. In most cases, an overdose occurs without long-term consequences.

Amino acid preparations

If the body has an acute deficiency of the amino acid in question, chewing walnuts and soy is not enough to bring its concentration back to normal. You have to replenish the supply of the substance by taking medications. Preparations with L-cysteine are made from synthetic or natural (for example, bone) substances. The second option is usually cheaper.

Unfortunately, it is not so easy to find a high-quality drug with the amino acid in question in the pharmacy. Most of them have a low dosage, poor bioavailability, or are completely counterfeit, which may not only be ineffective, but even dangerous to health. Drugs produced in the USA enjoy the best reputation.

Preparations with cysteine from the famous have proven themselves to be excellent.

This wonderful product is suitable for both professional athletes and those who simply want to improve their well-being, as well as the functional condition of their skin, nails and hair. The drug is supplied in dark glass bottles of 90 capsules. Each of them contains 500 mg of L-cysteine, which corresponds to the daily requirement. In case of acute deficiency of the substance in the body, you can take up to three capsules per day.

Cysteine preparations from the following manufacturers are also quite popular:

"Twinlab".
Sources Natural.
"Naw."
"Iherb".
Life Extension.
"NAK."
"Bluebonnet."

Reviews

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Cysteine

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On forums, buyers leave positive reviews about supplements. Consumers claim that cysteine helps fight alopecia, accelerates hair growth and makes it thicker. Women note an increase in skin tone and elasticity after starting to take the amino acid. Athletes write that the supplement normalizes heart function, gives vigor and energy, and improves digestion.

There are few negative reviews about cysteine. Some people complain of adverse reactions or lack of effectiveness of supplements.

Who first discovered the amino acid cysteine?

The study of amino acids at the end of the 19th century was the most promising area in organic chemistry, attracting dozens of scientists. Researchers from Germany have succeeded most in this. O. Bauman was the first to discover the amino acid cysteine when he studied sulfur-containing amino acids. In 1884, he described the formation of cysteine from cystine, which occurs when the amino acid is exposed to tin and hydrochloric acid. Later, in 1903, the German chemist E. Erlenmeyer was able to establish the chemical structure of the new substance. In parallel, L-cysteine was studied by researcher K. Merner, who in 1899 managed to isolate it from the substance of horns.

Cysteine and alcohol

The amino acid should not be consumed together with alcoholic beverages, since ethanol disrupts the metabolism of cysteine and the synthesis of glutathione. Doctors recommend taking dietary supplements based on it only to eliminate the unpleasant consequences of alcohol intoxication and protect the liver from the toxic effects of alcohol metabolites.

Cysteine is found in foods, but is poorly absorbed, so it is best taken as a dietary supplement. This substance is involved in the synthesis of glutathione and taurine, metabolism, and supports the health of the eyes, heart and blood vessels. Preparations based on it are available in capsules, tablets and powder (for sports nutrition). You can purchase high-quality dietary supplements at affordable prices in the iHerb online store.

What's the best way to take it?

Cysteine is contained in preparations in various forms: L-cysteine, N-acetylcysteine, cysteine hydrochloride, cysteine dipeptide, acestine. The use of one form or another of this substance depends on the purpose of the drug. Cysteine is also found in food products in the form of a registered additive E920, but this additive, although absolutely harmless, does not have any beneficial properties for the body. In addition, the amino acid is destroyed when heated, so using the supplement in this form becomes absolutely useless.

You can find various forms of cysteine on iHerb. These may be tablets, capsules or powders to be taken orally, or a liquid form such as eye drops. The effectiveness of the drug does not depend in any way on the form of use; their diversity is due only to ease of use.

It is recommended to use cysteine simultaneously with taking vitamin C. When taking the amino acid, it is necessary to increase the usual daily water intake for better absorption of the drug.

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Sources

Cysteine is present in foods with increased protein content. These include:

milk and all types of meat;
eggs and poultry meat;
legumes;
seafood;
buckwheat grain;
seeds and kernels of nuts.

The maximum concentration of cysteine is observed in Brussels sprouts and broccoli, sweet peppers, onions, herbs and heads of garlic.

@ Artem Shadrin – stock.adobe.com

More detailed information is presented in the table:

Products	Protein	Cysteine	C/W
Raw pork	20.95 g	242 mg	1,2 %
Raw chicken fillet	21.23 g	222 mg	1,0 %
Raw salmon fillet	20.42 g	219 mg	1,1 %
Egg	12.57 g	272 mg	2,2 %
Cow's milk, 3.7% fat	3.28 g	30 mg	0,9 %
Sunflower seeds	20.78 g	451 mg	2,2 %
Walnuts	15.23 g	208 mg	1,4 %
Wheat flour	13.70 g	317 mg	2,3 %
Corn flour	6.93 g	125 mg	1,8 %
Brown rice	7.94 g	96 mg	1,2 %
Soybean dry	36.49 g	655 mg	1,8 %
Whole peas, shelled	24.55 g	373 mg	1,5 %

Cooking food at high temperatures destroys the AA. However, a raw food diet does not solve the problem. Gastric secretions and intestinal microflora significantly interfere with the absorption of cysteine.

The most convenient form of obtaining AK is whey. In it, the sulfur-containing compound is presented as cystine (a double molecular block). Penetrating into the body, the block disintegrates and the substance is absorbed. The “enemies” of the natural process are pasteurization and repeated heating. Therefore, store-bought milk will never become a complete source of amino acids.