Last updated: August 11, 2021

Cysteine is an amino acid that has many different functions in the human body. It not only has a positive influence on the formation of collagen and thus on your skin, hair and nails, but is also important for your immune system. If you want to know more about the effect and intake of cysteine, you've come to the right place.

We are pleased that you have found your way to our great cysteine test 2021. We will provide you with all the information you need about cysteine. You will learn why the amino acid is so important for your body, how you can take it, what you need to bear in mind when taking it and how cysteine could play an important role in curing serious diseases.




The most important facts

  • Cysteine is a sulphur-containing amino acid and a component of proteins. The body can basically produce it itself. However, in certain life situations and in the case of illness, you can take cysteine in the form of preparations such as tablets or powder.
  • Cysteine has a positive influence on the formation of collagen and the immune system. Studies show that the intake of N-acetylcysteine (a derivative of cysteine) can have a positive effect on various diseases.
  • When self-medicating with cysteine, you should not take too much. An overdose leads to undesirable side effects. Only in the case of chronic diseases should you take more than 1.5 grams per day. Only small amounts are suitable as a dietary supplement.

The Best Cysteine: Our Picks

Guide: Questions you should ask yourself before buying cysteine

In order to inform you comprehensively about the state of science and the effect of cysteine, we have summarised the most important information in the following sections.

What is cysteine?

Cysteine, or L-cysteine, is a sulphur-containing amino acid that has important functions as a basic building block in the human body. It is a component of important amino acid chains that form various proteins, including keratin.

The amino acid cysteine is one of the proteinogenic amino acids that is considered non-essential. It is therefore not one of the eight essential amino acids that must be supplied to the body. The body can synthesise (produce) cysteine from the essential amino acid L-methionine.

A semi-essential amino acid such as cysteine is only essential for the body under certain conditions - for example, at certain ages or in the case of illness. Especially in newborns, some semi-essential amino acids such as cysteine are still essential.

L-cysteine is usually administered as a food supplement or medicine in the form of N-acetylcysteine (ACC), because cysteine easily oxidises to cystine and is therefore less stable than N-acetylcysteine. This chemical compound is a derivative of naturally occurring cysteine.

How does cysteine work?

The amino acid cysteine has two main functions in the human body: On the one hand, it is important for a strong immune system. On the other hand, it is important for the firmness and strength of the connective tissue. In addition, it is tested in the form of N-acetylcysteine in use against various diseases. In the following sub-chapters we will go into these points in a little more detail.

Cysteine for a strong immune system / Cysteine against HIV

Together with the amino acids glutamic acid and glycine, cysteine forms the tripeptide gluthation. This is formed in the liver and strengthens the human immune system and supports the detoxification of many harmful substances.

Cysteine is therefore an important antioxidant that protects the body from excessive free radicals (aggressive molecules that harm other molecules in the body). It also reduces the toxic effects of drugs and chemicals.

Several studies describe the importance of cysteine for an intact immune system. A healthy immune system needs a correct balance between oxidising and reducing substances. This balance is regulated to a large extent by the cysteine present in the body. A lack of cysteine is therefore detrimental to the immune system (1).

For this reason, HIV patients have also been found to have an insufficient amount of cysteine and thus gluthation in the body. The deficiency of cysteine in the body of HIV patients leads to their weakened immune systems. There is therefore the possibility that a therapy with N-acetylcysteine could increase the level of cysteine and gluthation in the body again and thus strengthen the immune system of HIV patients again (2, 3, 4).

Cysteine for beautiful hair and nails

Cysteine is also involved in the production of collagen and is thus a building block for hair keratin. Together with the B vitamins, it is therefore particularly important for hair growth and helps with hair loss. It also contributes to the development of skin and nails.

A study showed that a six-month diet enriched with L-cysteine, yeast and B vitamins had a positive effect on hair growth in healthy women with hair loss. After three months, a normalisation of hair growth was already observed in these women (5).

Cystein-1

Cysteine is involved in the production of collagen and is therefore very important for hair.
(Image source: unsplash.com / Yoann Boyer)

Cysteine against inflammation

Cells in the organism can lose their ability to balance between oxidising and reducing substances. This leads to so-called oxidative stress.

A study has shown that a high level of oxidised cysteine can trigger inflammation in the body. Targeted therapy with cysteine in the form of food intake can therefore help against inflammation, which in turn reduces heart problems, among other things (6).

Cysteine against lung diseases

Oxidative stress also leads to lung diseases. The weakened immune system can lead to infections, which weakens the lung capacity. N-acetylcysteine has been used as an antioxidant in patients to relieve their symptoms and prevent the deterioration of lung function (7).

Also, the effect of N-acetylcysteine was tested in patients with chronic bronchitis. The results showed that patients taking N-acetylcysteine orally relieved symptoms and reduced the risk of further deterioration (8).

Cysteine for strong bones

When inflammatory cells invade bone and cartilage tissue, this promotes the destruction of cartilage and thus joints. The antioxidant effect of N-acetylcysteine would help against joint inflammation (9).

Another study showed that cysteine has a strong effect on bone mineral density. Patients with cysteine in their bodies thus also have a lower bone mineral density and thus suffer more bone fractures (10).

Cysteine against heart problems

Studies have shown that intravenous administration of N-acetylcysteine during thrombolysis reduces infarct size and improves ventricular function. Researchers have found that intravenous or oral administration of N-acetylcysteine in patients with heart problems also reduces the chance of a heart attack (11).

Cysteine against cancer

In animal models and in vitro, N-acetylcysteine was able to break down carcinogens, repair DNA and inhibit the further development of tumour cells (12).

In human studies, however, the anticancer effect of N-acetylcysteine could not be proven. In a EUROSCAN study, patients with carcinomas in the lungs were given 600 mg of N-acetylcysteine per day for two years. No higher protective effect was found compared to the control group, which was given a placebo (13).

When and for whom is it worth taking cysteine preparations?

Basically, taking cysteine (in controlled amounts) is worthwhile for all people. The strengthening of the immune system and connective tissue is beneficial for every gender and age.

What the various studies show is that in certain life situations - especially with certain diseases - taking cysteine can also be very influential.

What side effects can the intake of cysteine have?

L-cysteine has hardly any undesirable side effects. Cysteine, acetylcysteine or gluthation are not known to interact with medicines or other nutrients.

For diabetics, however, it is important that they only use cysteine under medical supervision. A high dosage can inhibit insulin and thus make it difficult to control blood sugar.

Also, if you take N-acetylcysteine for a long time (longer than one month), you should also take an amino acid complex to ensure a balanced supply of all amino acids.

Another side effect of taking N-acetylcysteine is the excretion of copper in the urine. In this case, you should therefore take plenty of copper and zinc.

Also, high doses sometimes lead to gastrointestinal problems, fatigue or, in extreme cases, even kidney and bladder stones. Pregnant women are not recommended to take cysteine because the effects have not yet been researched.

What alternatives are there to cysteine preparations?

Of course, you can buy various other amino acids that are also good for your health. The immune system-boosting L-gluthation is also available on Amazon.

Also, taking various B vitamins, vitamins C and D and the minerals iron and zinc is always good for your immune system, your skin and your health in general.

The vitamin biotin and the mineral zinc especially drive the L-cysteine metabolism. These help you to maintain a healthy cysteine content in your body.

Decision: What types of cysteine are there and which is right for you?

Cysteine is primarily available for purchase in two different preparations. These are:

  • Cysteine tablets
  • Cysteine Powder

We will explain the advantages and disadvantages of both variants in more detail in the following paragraphs.

Cysteine tablets

Cysteine preparations in tablet form are often highly dosed. So one tablet is usually enough to restore the daily cysteine requirement.

Cystein-2

Cysteine in tablet form is a good choice if you want the dosage to be very precise and simple.
(Image source: unsplash.com / The-Lore.com)

Many tablets are also vegan and contain a minimum of additives. It is recommended to take them half an hour before lunch.

There are also cysteine tablets that are additionally enriched with B vitamins and vitamin C. This strengthens the skin, hair and nails. This further strengthens the skin, hair and nails.

Advantages
  • Highly dosed, easy rationing
  • often vegan, few additives
  • sometimes enriched with vitamins
Disadvantages
  • Slightly more expensive than the powder
  • Used up quicker than the powder
  • Might be hard to swallow for some people

Unfortunately, the tablets are usually a bit more expensive compared to the powder. They are also generally used up more quickly.

Also, the capsules are not very small and should be swallowed whole. This could possibly be somewhat unpleasant for some people.

Cysteine powder

Cysteine powder is generally the cheaper option compared to tablets. The powders also contain few other additives.

Cystein-3

Cysteine in powder form is often cheaper than the tablets and easier to consume.
(Image source: unsplash.com / Adrien Olichon)

It is also certainly easier for some people to consume. You can simply add the powder to a glass of water and drink it.

Advantages
  • Cheaper than tablets
  • Easy to consume
  • Few other additives
Disadvantages
  • Somewhat unpleasant smell
  • Dosing a little more difficult than with tablets

The powder might smell a little unpleasantly sour. This smell is due to the sulphur content of cysteine.

In addition, the dosage of the powder may be a little more difficult. A recommendation is to take about 0.5 grams per day. The products often come with a measuring spoon, so rationing should be easy.

Purchase criteria: You can compare and evaluate cysteine preparations based on these factors

You can distinguish between cysteine preparations based on various criteria. We have summarised the following differentiating factors for you here:

In the following paragraphs we will explain to you what is important in the individual criteria.

Dosage form

As already mentioned above, you can distinguish between cysteine preparations based on their different dosage forms. In the upper chapter we have already shown you the advantages and disadvantages of tablets and powder.

For larger quantities, the tablets and the powder differ mainly in price. The powder is probably the better option for you if you are less fond of taking tablets. The tablets are usually in higher doses, which makes rationing easier.

Dosage

The dosage of cysteine is an important point, as you should never exceed the recommended amounts. Tablets have the advantage that you do not have to ration yourself. Also, the dosage is often so high that one tablet a day is completely sufficient. The dosage is also reflected in the price. The high-dose tablets are usually more expensive.

The powder often comes with a measuring spoon with which you can precisely measure the amount of cysteine to be taken. Overdosing on acetylcysteine is very unhealthy in the long run.

Amount of content

Another criterion is the amount of cysteine in the preparation. There are differences here, especially in the tablets. There are packages with between 100 and 360 tablets.

You can also buy different quantities of powders. Amazon, for example, offers acetylcysteine powder in quantities of 100 or 500 grams.

Other ingredients

Finally, you can distinguish between cysteine preparations on the basis of their other ingredients. The powders often have no additional ingredients and consist of pure acetylcysteine.

The tablets, on the other hand, are sometimes enriched with additional vitamins. You also have to include the capsule shell as an additive. In the meantime, these are also produced from plants.

Facts worth knowing about cysteine

Now that you have collected some information about cysteine and its available preparations, we would like to give you a few more tips. Here you will find valuable tips for taking cysteine - with preparations as well as through food.

When and for how long should I take cysteine supplements?

Cysteine can be taken as a dietary supplement to strengthen the immune system or for skin problems. Self-medication is always prone to overdoses. Therefore, you should closely monitor your cysteine consumption.

Of course, the amount and duration of cysteine intake always depends on your health. Basically, it is important that you do not take high amounts for too long. Even if you have health problems, you should not take more than 1.5 grams of cysteine for longer than one month.

How much cysteine should I take?

The daily cysteine requirement for healthy adults is 13 milligrams per kilogram of body weight. This requirement is normally met with a balanced diet. However, in the case of health problems such as immune deficiencies or also various skin problems, an additional intake of cysteine can make sense.

To cover the daily requirement, between 0.5 and 1.5 grams of cysteine can be taken as a food supplement. In people with chronic diseases, however, the body's own cysteine synthesis is often limited. Therefore, they can take a somewhat larger amount over a certain period of time (for example, 1 gram 3 times a day for a month).

Cysteine can also be administered with other nutrients with which cysteine develops synergies. One such nutrient would be vitamin C, which you can take in a 1:3 ratio with cysteine (for example, 500 mg of cysteine to 1500 mg of vitamin C).

What foods contain cysteine?

Cysteine is a proteinogenic amino acid and is therefore found in various protein sources, especially animal ones. However, soy products have the highest cysteine content. The following table provides an overview:

Food Number of cysteine per 100 grams
Chicken breast 222 mg
Pork 242 mg
Salmon 219 mg
Chicken egg 272 mg
Soybeans 665 mg
Sunflower seeds 451 mg
Peas 373 mg

(Source: https://vitup.ch/vitalstoffe/l-cystein)

Are cysteine preparations vegan?

Cysteine preparations are not always vegan. They can be made from animal products. Therefore, it is always worth taking a close look at the ingredients.

During our research we found some cysteine preparations in tablet form that are one hundred percent vegan. Even the capsule shell, which was often made from animal products, is now made from plants.

References (13)

1. Modulation of lymphocyte functions and immune responses by cysteine and cysteine derivatives Dröge, Wulf et al. The American Journal of Medicine, Volume 91, Issue 3, S140 - S144
Source

2. Dröge W., Eck H. P., Mihm S. HIV-induced cysteine deficiency and T-cell dysfunction—a rationale for treatment with N-acetylcysteine. Immunology Today. 1992;13(6):211–214. doi: 10.1016/0167-5699(92)90156-2.
Source

3. Dröge, W. Cysteine and Glutathione Deficiency in AIDS Patients: A Rationale for the Treatment with IM-Acetyl-Cysteine. Pharmacol. 1993, 46, 61–65.
Source

4. De Rossa SC, Zaretsky MD, Dubs JG, Roedera M, Anderson M, Green A. N-acetylcysteine replenishes glutathione in HIV infection. Eur J Clin Investig. 2000;30(10):915–25.
Source

5. W. Gehring, M. Gloor, “Das Phototrichogramm als Verfahren zur Beurteilung haarwachstumfördernder Präparate am Beispiel einer Kombination von Hirsefruchtextrakt, L-Cystin und Calciumpanthotenat”, Zeitschrift für Hautkrankheiten, 2000; 75(7/8):419-423
Source

6. Emory University. "Targeting Oxidized Cysteine Through Diet Could Reduce Inflammation And Lower Disease Risk." ScienceDaily. ScienceDaily, 31 March 2009. .
Source

7. Dekhuijzen PN (2004) Antioxidant properties of N-acetylcysteine: their relevance in relation to chronic obstructive pulmonary disease. Eur Respir J, 23(4): 629–636.
Source

8. The effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review. Stey C, Steurer J, Bachmann S, Medici TC, Tramèr MR. https://erj.ersjournals.com/content/16/2/253.long. Eur Respir J. 2000;16:253–262.
Source

9. Nakagawa S, et al. N-acetylcysteine prevents nitric oxide-induced chondrocyte apoptosis and cartilage degeneration in an experimental model of osteoarthritis. J. Orthop. Res. 2010;28:156–163.
Source

10. Baines, M. , Kredan, M.B. , Davison, A. . The association between cysteine, bone turnover, and low bone mass. Calcif Tissue Int. 2007; 81(6): 450–4.
Source

11. Marchetti G, Lodola E, Licciardello L, Colombo A. Use of N-acetylcysteine in the management of coronary artery diseases, Cardiologia , 1999, vol. 44 7(pg. 633-637)
Source

12. De Flora S, Izzotti A, D’Agostini F, et al. Mechanisms of N-acetylcysteine in the prevention of DNA damage and cancer, with special reference to smoking-related end-points. Carcinogenesis 2001;22:999–1013.
Source

13. Van Zandwijk N., Dalesio O., Pastorino U., de Vries N., Van Tinteren H. EUROSCAN, a randomized trial of vitamin A and N-acetylcysteine in patients with head and neck cancer or lung cancer. For the European Organization for Research and Treatment of Cancer Head and Neck and Lung Cancer Cooperative Groups. J. Natl. Cancer Inst. 2000;92:977–986. doi: 10.1093/jnci/92.12.977.
Source

Why you can trust me?

Wissenschaftliche Studie
Modulation of lymphocyte functions and immune responses by cysteine and cysteine derivatives Dröge, Wulf et al. The American Journal of Medicine, Volume 91, Issue 3, S140 - S144
Go to source
Wissenschaftlicher Review
Dröge W., Eck H. P., Mihm S. HIV-induced cysteine deficiency and T-cell dysfunction—a rationale for treatment with N-acetylcysteine. Immunology Today. 1992;13(6):211–214. doi: 10.1016/0167-5699(92)90156-2.
Go to source
Wissenschaftlicher Review
Dröge, W. Cysteine and Glutathione Deficiency in AIDS Patients: A Rationale for the Treatment with IM-Acetyl-Cysteine. Pharmacol. 1993, 46, 61–65.
Go to source
Klinische Forschung
De Rossa SC, Zaretsky MD, Dubs JG, Roedera M, Anderson M, Green A. N-acetylcysteine replenishes glutathione in HIV infection. Eur J Clin Investig. 2000;30(10):915–25.
Go to source
Wissenschaftliche Studie
W. Gehring, M. Gloor, “Das Phototrichogramm als Verfahren zur Beurteilung haarwachstumfördernder Präparate am Beispiel einer Kombination von Hirsefruchtextrakt, L-Cystin und Calciumpanthotenat”, Zeitschrift für Hautkrankheiten, 2000; 75(7/8):419-423
Go to source
Wissenschaftliche Forschung
Emory University. "Targeting Oxidized Cysteine Through Diet Could Reduce Inflammation And Lower Disease Risk." ScienceDaily. ScienceDaily, 31 March 2009. .
Go to source
Wissenschaftlicher Review
Dekhuijzen PN (2004) Antioxidant properties of N-acetylcysteine: their relevance in relation to chronic obstructive pulmonary disease. Eur Respir J, 23(4): 629–636.
Go to source
Wissenschaftliche Analyse
The effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review. Stey C, Steurer J, Bachmann S, Medici TC, Tramèr MR. https://erj.ersjournals.com/content/16/2/253.long. Eur Respir J. 2000;16:253–262.
Go to source
Wissenschaftliche Studie
Nakagawa S, et al. N-acetylcysteine prevents nitric oxide-induced chondrocyte apoptosis and cartilage degeneration in an experimental model of osteoarthritis. J. Orthop. Res. 2010;28:156–163.
Go to source
Wissenschaftliche Studie
Baines, M. , Kredan, M.B. , Davison, A. . The association between cysteine, bone turnover, and low bone mass. Calcif Tissue Int. 2007; 81(6): 450–4.
Go to source
Wissenschaftlicher Review
Marchetti G, Lodola E, Licciardello L, Colombo A. Use of N-acetylcysteine in the management of coronary artery diseases, Cardiologia , 1999, vol. 44 7(pg. 633-637)
Go to source
Wissenschaftliche Studie
De Flora S, Izzotti A, D’Agostini F, et al. Mechanisms of N-acetylcysteine in the prevention of DNA damage and cancer, with special reference to smoking-related end-points. Carcinogenesis 2001;22:999–1013.
Go to source
Klinische Forschung
Van Zandwijk N., Dalesio O., Pastorino U., de Vries N., Van Tinteren H. EUROSCAN, a randomized trial of vitamin A and N-acetylcysteine in patients with head and neck cancer or lung cancer. For the European Organization for Research and Treatment of Cancer Head and Neck and Lung Cancer Cooperative Groups. J. Natl. Cancer Inst. 2000;92:977–986. doi: 10.1093/jnci/92.12.977.
Go to source
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