L-cysteine is used therapeutically and nutritionally to improve the health of humans. It’s a basic building block of glutathione, which has been coined “the mother of all antioxidants.” L-cysteine supplementation, also known as N-acetyl-L-cysteine (NAC), is valued for its ability to increase glutathione levels in the body, which is extremely important for lung function, brain function and liver detoxification. Because a number of health conditions deplete your glutathione levels, you need L-cysteine to make more within your brain and body tissues.
L-cysteine is also valued for its ability to break up mucus, thereby making it easier to cough up phlegm that’s caused by respiratory and pulmonary conditions. Plus, L-cysteine is involved in regulating glutamate levels, influencing the neurons in the central nervous system.
In a nutshell, we all need enough L-cysteine in order to properly fight oxidative stress and conditions affecting the brain and lungs. L-cysteine is made in small amounts by the human body, and you can also get L-cysteine from high-protein foods and supplementation.
What Is L-cysteine?
L-cysteine is classified as a “semi-essential” amino acid because it can be made in small amounts by the human body, but many people can still benefit from consuming more cysteine from their diets or supplements because of its numerous health benefits. The human body can usually manufacturer L-cysteine from the amino acids serine and methionine, but you need enough folate, vitamin B6 and vitamin B12 for that to be possible.
Along with two other amino acids, glutamine and glycine, L-cysteine is needed to make glutathione, the master antioxidant that’s crucial for your health. L-cysteine is usually the amino acid that’s in shortest supply for making glutamine, so it’s important that you get enough of this amino acid, even though it’s not considered essential.
Although L-cysteine is a minor scavenger of oxidative stress, its most important role is reviving glutathione, one of the most powerful antioxidants in the body. Longevity researchers believe that glutathione is so pivotal to your health that the level of this antioxidant in your cells may be a predictor for how long you will live. It’s the body’s most important antioxidant because it is within the cell, making it essential for maintaining a healthy immune system and fighting cellular damage.
7 L-cysteine Benefits
1. Has Antioxidant Properties
L-cysteine works as a scavenger of free radicals that cause cellular damage through oxidative stress, and it improves antioxidant capacity through the preservation of glutathione. This is the most well-known L-cysteine benefit because it can slow down the aging process and help prevent or treat a number of serious health conditions.
This also means that by boosting your levels of glutathione, L-cysteine supports immune function. Research suggests that immunological functions in diseases that are associated with a cysteine and glutathione deficiency may be significantly enhanced and potentially restored by L-cysteine supplementation.
There are studies involving HIV patients that show L-cysteine’s ability to boost your immune system. One study conducted in Europe showed that a formulation including NAC, bovine colostrum, omega-3 fatty acids, and a combination of vitamins and minerals slowed down the decline of immune cells. Another study showed that by replenishing glutathione levels, L-cysteine appears to have a beneficial impact on the immune function of people living with HIV.
L-cysteine supplementation can also improve immune function in postmenopausal women, as indicated by a 2008 study published in Free Radical Biology and Medicine. The study found that a short period of NAC supply, such as two to four months, may lead to prolonged strengthening of immune defense in postmenopausal women. Researchers concluded that NAC supplementation can contribute to the maintenance of good health and quality of life in postmenopausal women by decreasing the probability of immune system-related diseases (such as infection) as they age.
2. Promotes Detoxification
L-cysteine can be used to help prevent side effects caused by drug reactions and toxic chemicals. According to research published in Alternative Medicine Review, cysteine plays a pivotal role in the detoxification mechanisms in the body. Toxic metals have pro-oxidative effects, and they deplete glutathione levels, so L-cysteine supplements help restore those levels so that you can properly detoxify toxins.
Because L-cysteine helps the body to detoxify dangerous toxins and chemicals, it’s common for doctors to give intravenous NAC to people who are having an acetaminophen overdose in order to prevent or reduce liver and kidney damage. Drug-induced acute liver failure is a fatal disease that’s caused by the toxic metabolite, N-acetyl-p-benzoquinone-imine, that leads to glutathione depletion. When overdose patients are treated with NAC, this allows for a significant increase in glutathione activity.