L-Cysteine Overview | Nu Image Medical®

Dr. Constance Odom, MD

Medically reviewed by

Dr. Constance Odom, MD

Dr. Constance Odom, MD

About

Constance Tambakis Odom, MD graduated in 1987 with her Doctorate of Medicine from the New York Medical College, and was an Anesthesiologist Resident from 1988 to 1991 at the Brookdale Medical Center PGY II (CA-I)-PGY IV (CA-III). She is Board Certified by the American Board of Anesthesiology since 1998 and American Academy of Anti-Aging Medicine since 2002. Constance Odom, MD is affiliated with the American Medical Association, American Academy of Anti-Aging Medicine, American Society of Anesthesiology, Georgia Society of Anesthesiology, Hellenic Medical Society of New York, North Carolina Society of Anesthesiology, and Society of Ambulatory Anesthesia.

Credentials

Medical Director At:

• Nu Image Medical
• MetroMedispa P.A.

Staff Anesthesiologist at:

• Betsy Johnson Regional Hospital in Dunn, NC
• Onslow Memorial Hospital in Jacksonville, NC
• Duplin General Hospital in Kenansville, NC

Director of Anesthesia Services at:

• Jacksonville Surgery Center in Jacksonville, NC

Written by our editorial team.

Last Edited 6 years ago · 4 min read

L-Cysteine is often used for therapeutic purposes as well as for nutritional well-being. It’s a glutathione building block, and is often referred to as “the other” of antioxidants. It is known as NAC and the supplement aids in: liver function, brain function, cognitive health, and can aid in detoxing the liver. Glutathione levels are depleted by any illnesses, and for this reason, a L-Cysteine supplement is extremely useful. The antioxidant is also used to help treating the common cold; as it breaks up mucus, it is often used by individuals who are sick and want to get back on their feet quickly. Although you can get levels of L-Cysteine from certain foods, most people don’t get enough, and this is where NAC supplements come into effect.

What is L-Cysteine?

Classified as a “semi” essential amino acid, the human body produces it in small amounts, however most people don’t produce enough, resulting in a deficiency. Although amino acids help the body build up levels, typically not enough is built up through diet alone. Glycine and glutamine, along with L-Cysteine make up glutathione. This is the master of all amino acids, and the body requires it for optimal health and functionality; for this reason, you need to get enough L-Cysteine to produce the “main” amino acid.

The main role of L-Cysteine is to revive glutathione levels which are depleted. When present in high volumes, this helps improve immune health, and overall bodily functions, so you not only feel better, you are healthier as well.

The benefits: Why you need L-Cysteine

1. Antioxidants 

You know your body needs antioxidants, but it doesn’t produce high enough levels on its own. As a “scavenger” of free radicals, L-Cysteine not only helps eliminate toxins and waste, but also builds up levels of antioxidants naturally. It can also help slow down the aging process, which is something most users are going to appreciate greatly.

A number of studies involving HIV patients have been conducted using L-Cysteine supplements. It has shown a significant boost in the immune system, bovine colostrum levels, omega-3 levels, and slows down decline of immune health. Replenishing glutathione levels is also helpful in improving immune health in HIV-sufferers.

For post-menopausal women, L-Cysteine can also help improve mood and wellbeing. It can lead to prolonged immune system health and contribute to maintenance of good health. It also helps lessen the probability of immune system failure or poor health.

1. Detoxing

L-Cysteine is also important to help detox the body, help eliminate free radicals, and help eliminate toxins which build up naturally. It will help with liver detoxification, which helps push bile out of the system. So, in addition to improved immune health, it may possibly help in reving up the metabolism and helping you burn a few extra calories each day as well.

Toxic metals and other harmful toxins deplete glutathione health; with L-Cysteine supplements, you can easily rebuild and revitalize your system. It helps restore deplted levels quickly and naturally.

Many doctors even use L-Cysteine in treating patients who’ve had an acetaminophen overdose, as it helps remove metal toxins from the system. A significant increase in glutathione levels will help push the harmful toxins out of the system faster.

1. Male fertility increased

By increasing depleted glutathione levels caused by oxidative stress, it can be an effective infertility treatment as well. Studies have shown L-Cysteine to increase varicocele levels in infertile males; child pregnancy rates in test subjects went up 33%, in comparison to 10% which was previously reported.

1. Blood sugar balance

It can help your body regulate and naturally manage blood sugar levels. When taken in proper dosage, L-Cysteine will naturally help the body revert to its original state. So, those who have low or high blood sugar levels, will find the supplement can help greatly improve those levels. Plasma protein oxidation level increases were also noted in test subjects (rats) who were given an L-Cysteine supplement.

1. Improve digestion

Many people suffer from poor digestive health; L-Cysteine supplements can help regulate and improve the digestive tract, so you process foods easily. It can help resolve issues like low stomach acids, which doesn’t allow you to break down certain compounds in foods. It will also help reduce free radicals in the body, which are also a culprit of poor digestive health.

UC levels can also go down with the use of L-Cysteine supplements. The inflammatory bowel disease can be improved upon simply by incorporating the supplement, and can decrease chemokins (which increase blood cells and free radical count). All these factors working together, will naturally help improve the digestive tract, and overall digestive health.

1. Stomach & Respiratory Condition Relief 

Working as an expectorant, it can naturally break down mucus. So, if you are sick, have the flu, or suffer from breathing conditions, L-Cysteine supplements can help improve upon these conditions as well. Boosting glutathione levels will also help you breathe easier, eliminate congestion, and help you feel better all around. Those who suffer from COPD, bronchitis, or other respiratory conditions, will experience a great deal of relief by simply incorporating a L-Cysteine supplement.

Oxidant burden and inflammation found in COPD sufferers, are naturally decreased when L-Cysteine is present in high volumes in the body. Patients who suffer from COPD have often use L-Cysteine in treating the condition, and helping improve how they feel because of the condition.

1. Psychiatric disorder treatment

Several research studies suggest NAC supplements can help those who suffer from psychiatric conditions. NAC has the potential for helping those who suffer from addiction, or marijuana addiction, nicotine, or cocaine addiction. Even pathological gambling has been treated with the use of L-Cysteine supplements. OCD sufferers can also benefit from NAC supplements, as they can help stop the “triggers” for your compulsion.

It has also been used in treating bipolar disorder and schizophrenia .Because of the antioxidant activity, this naturally helps enhance your mood; so, individuals who suffer from the conditions, are less likely to experience the multiple-personalities. L-Cysteine is also capable of helping mimic glutamate; so, this can help in treating schizophrenia, or prevent certain disorders, where a shortage occurs.

Some studies have also shown L-Cysteine can help treat conditions like: acne, angina (which restricts bloodflow to the heart), asthma, colon cancer, lung cancer, and other conditions.

Foods & Recipes: Where to get L-Cysteine Naturally 

The truth of the matter is that proper diet is typically enough to cure many of the deficiencies we suffer from; and, yes, this does include L-Cysteine. But, you simply can’t eat enough chicken breast and broccoli, to undo the many years of poor diet and malnutrition. For this reason, most people who are deficient in L-Cysteine, glutathione, and other essential amino acids, vitamins, and minerals, rely on the power of supplements to help cure those deficiencies.

There are a number of foods which contain high levels of L-Cysteine; however, most of us simply do not consume sufficient levels of these foods, in order to account for a deficiency. Some of the foods you can find L-Cysteine in, include: chicken, duck, turkey, pork, eggs, yogurt, cheese, legumes, oat, and sunflower seeds. The problem being is most of us simply don’t consume enough of these foods on a routine basis.

Amino acids serine is how the body processes L-Cysteine and methionine. However, for this to occur, folate, potassium, vitamin B6, B12, and other essential vitamin and mineral levels have to be at the appropriate level. Many of these vitamins come from cheese, dairy, legumes, soy, and other foods. Even salmon, liver, and tuna can help increase these levels in your body naturally.

Need a few simple recipes to help you get those foods into your diet? You can try a few of these out. Not only are they extremely easy for you to make, but you can simply set them in the crockpot and they will be ready when you get home from work. Very little prep, and easy to make recipes, are naturally going to increase folate, vitamin, potassium, and yes, eventually your L-Cysteine levels in no time.

Of course, in addition to eating well and choosing the right foods to add to your diet, it is still essential to ensure you are getting sufficient levels of this amino acid booster. So, relying on a L-Cysteine supplement, along with the changes in diet, and incorporating of these foods more routinely, is the best way to ensure proper levels are achieved when you are trying to treat a deficiency.

L-Cysteine: Dosage and supplement options

NAC is what is found in supplement forms for those who are treating a L-Cysteine deficiency, researchers have found it to effectively treat many illnesses. From replenishing intracellular levels of glutathione , to treating inflammation, or stomach conditions and disorders, when used at appropriate levels, NAC is highly effective. It can also inhibit inflammation, which is associated with many cardiovascular conditions and respiratory conditions.

What forms should you take? 

The forms of L-Cysteine which are available include:

• NAC Aerosol spray: This is often used in treating respiratory conditions, lung conditions, or difficulties in breathing. In order to use it, a doctor prescription is required.

• Tablets or capsules: The L-Cysteine capsules or tablets can be used for antioxidant boost, or general health and wellbeing. No prescription is required for use of these supplements.

  • Standard dosage is 500 mcg daily.

  • Adults treating a respiratory condition can take two daily, up to 200-600 mcg.

  • Those using it to treat COPD will find 600 mcg to be the most effective dosage level (or higher) in most cases.

• NAC liquid solutions are available.

• NAC topical solutions are available.

• L-Cysteine powder is also available for some users.

Incorporating a B-vitamin or a multivitamin is also good practice when using L-Cysteine or NAC supplements. This will simply ensure you are getting sufficient levels of B-vitamin and other essential vitamins the body requires.

Precautions & Side effects: Are there any? 

When taking L-Cysteine or NAC supplements, it is important to note, that like any supplement, vitamin, or mineral, the possibility of experiencing some side effects is always possible. These are rare, they are typically minor, and they are more so linked to those who are on other prescriptions, or already have a preexisting condition they are treating.

If you are taking very high doses of NAC, this is one of the most common reasons side effects will be experienced; it can be toxic in human cells when you are using too much L-Cysteine through a supplement form. It is important to keep track of dosage and talk to your doctor, to ensure safe levels of dosage. And, when treating a chronic condition, make sure you monitor levels and frequency of L-Cysteine used.

If you already use other medications for immune health or which suppress the immune system, it is advised that you do not use L-Cysteine or NAC supplements either. If using medication for high cholesterol or allergies, it is important to discuss with your doctor, to determine if you can incorporate the NAC supplement or not.

Dry mouth, dizziness, headaches, nausea, and vomiting, are among the most commonly reported side effects by those who are taking a L-Cysteine supplement. If you begin to experience any of these, talk to your doctor before you continue use. Often, simply reducing the levels, or learning about other medications, is an easy way for your doctor to decide if you should use or cease using the L-Cysteine supplements.

Final thoughts

Now that you know what L-Cysteine is for, how it can benefit you, and how it can improve overall health, general health and wellbeing, and immune health, you are thinking about whether or not you should be taking a supplement. The answer is, it depends. And, for every individual it is going to be a different response. For some, you can use it to treat chronic conditions, while others are simply trying to treat a glutathione deficiency. Regardless of reason for use, or dosage, it is important to talk to a doctor before you begin using L-Cysteine supplements.

1. L-Cysteine: it is a highly valued supplement. In the NAC form, it can naturally help increase glutathione levels. This, “mother of all” antioxidants, is going to improve overall health, wellbeing, increase energy levels, and can help you fight colds and other illnesses naturally.

By working as an antioxidant in the body, it helps promote heart health, liver health, brain function, cognitive health, and liver detoxification. All natural remedies the body needs. It can also improve respiratory conditions, and help treat conditions like COPD or asthma, when taken in a prescribed form, in the appropriate dosage levels.

1. L-Cysteine: typically it is the shortest in supply of all amino acids. So, even if you are eating foods which contain it, and are following a balanced diet, you are likely deficient in it. And, as it is the shortest supply in making glutamine, it is highly important that you are getting enough L-Cysteine or NAC in your system. Even though it is not an “essential” amino acid, it is one which will help boost levels of glutamine and glutathione naturally, so why not incorporate a supplement if you are not taking one? It is only going to benefit you, and help in naturally improving energy, overall health, and wellbeing in the long run.

2. L-Cysteine: It can be found in foods. High and rich-protein foods, are often linked to having high levels of NAC in them. Chicken, duck, fish, tuna, and dairies, such as yogurt or milk, contain this component. Further, you can also get it from legumes. You can easily incorporate a few of the above listed recipes into your diet, to help increase L-Cysteine naturally. And, when eaten regularly, and taken aside a supplement, it is going to work to increase levels faster than if you are trying to get NAC from foods alone.

3. L-Cysteine: NAC. This is the form of L-Cysteine which is found in supplements you are taking. So, whether it is a nasal spray, capsule, pill, ointment/rub, or topical solution you are using, it is NAC which is going to be absorbed into your system, and processed to help increase glutamine and glutathione levels which are depleted. NAC has been proposed, by many researchers, to treat a number of illnesses and conditions. Ranging from chronic conditions, liver conditions, mental health, the common cold, or even reducing the possibility that you will suffer from schizophrenia or bipolar disorder, are a few of the many treatments which NAC has been a part of. And, with clinical studies and positive results backing those studies up, you can be rest assured it is going to benefit you if you are using the supplement form of NAC.

4. L-Cysteine: When taking the NAC supplement form, if you are taking too high a dosage, it can result in toxicity in the human body. As it is linked to metal or alkaline, it is important to note that it is highly toxic. This however, is only the case, when it is taken in very high dosages. So, those who are using it for COPD, liver disease, or other “more severe” conditions, it is important to discuss the risk of toxicity in the blood stream, with your doctor. When prescribed, your doctor is going to inform you of the risks. But, you do have to make sure you are monitoring use, monitoring the levels, and maintaining the right dosage levels, to avoid this possible complication from arising. When taken at appropriate levels, NAC is highly effective in treating several conditions and disorders.

Is NAC right for you?

Again, this depends. As detailed above, some people simply can’t take L-Cysteine supplements. This is because of the high toxicity levels. Additionally, those who are on other prescriptions, are taking medication for high cholesterol, or suffer from certain disorders are not going to be able to use L-Cysteine safely. So, even though it is highly effective and can treat various illnesses, it is important to discuss use with a doctor, prior to using NAC supplements, or ordering them online for use.

For those who can safely use L-Cysteine supplements, it is still important to discuss use with your doctor. Not only to monitor the levels, and avoid toxicity concerns, but also to ensure you are using the right solution (nasal spray, pill, topical, etc.), to treat the condition or illness you are trying to improve. If you are not taking the right form of NAC, and are not getting sufficient dosage, it is not going to benefit you in the manner it should. Therefore, prior to starting use of this supplement, it is important to discuss it with your doctor, to learn if it is the right form for you, in treating a particular illness of condition that you suffer from.

There is more than one form of NAC, and for some users, one is going to be inferior than others. Further, there are some which will require a prescription, and some forms can only be taken at certain dosage levels. Understanding how to use the supplement safely, and how NAC will benefit you, is the starting point for those who would like to incorporate this supplement into their diet, in order to treat L-Cysteine deficiencies. No two people are alike, so no two individuals are going to rely on the same form or dosage of a particular supplement, in order to treat an illness.

Whether it is to improve immune health, treat a chronic condition, or boost energy levels, L-Cysteine can help. NAC supplements are where you are going to find L-Cysteine, which you can include into your diet, when you are not getting sufficient levels from foods alone. These are a few of the many things you should be familiar with, if you plan on using the supplement. It is also important to talk to your doctor, discuss complications, and list any medications you are currently taking. This will allow them to decide which form and dosage of NAC to put you on, and how to go about incorporating this supplement naturally into your diet.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.