L-Cysteine Side Effects, Toxicity and Safe Dosages

L-Cysteine supplements are used as anti-aging supplements, to promote skin and hair health, to boost the immune system, combat osteoporosis and as an anti-inflammatory.

This amino acid promotes the synthesis of Glutathione, which is a powerful natural anti-oxidant. It helps to eliminate toxins in the body and to build and maintain cell membranes and the myelin sheaths that protect neurons in our brain.

But before you consider taking this supplement, it is important to be aware of the possibility for L-cysteine side effects if it is not used properly. Excess dosages can cause unwanted adverse effects, and all drugs and supplements have a toxicity level to be aware of.

Cysteine

Amino Acid

Skin

Hair

Anti- Aging

How It Works:

• Promotes healthy skin, hair & nails
• Aids in the formation of collagen
• Supports protein structure for anti-aging

Dosage:

Between 200 - 500 mg per day

Safety:

Generally Well Tolerated

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Why We Need L-Cysteine

As much as we would all like to supply ourselves with optimal nutrition from food, at times it may be difficult to eat the way we need to.

In order to safeguard our health from deteriorating, it is sometimes worth supplementing our nutritious diets with vitamins, minerals and amino acids such as L-cysteine.

L-cysteine is a conditionally essential amino acid that is needed by our bodies in order to build and repair tissue. It is also a key component of hair, nails and skin cells.

By ‘conditionally essential’ we mean that the body, under normal circumstances, can make a certain amount of L-cysteine. When certain adverse conditions are present, such as metabolic disorders, we may not produce enough L-cysteine to maintain important structures and functions in our bodies.

Even when the body is manufacturing this amino acid, there are circumstances where the body may benefit from supplementation. One example, of a time when the body may need additional L-cysteine, is during soft tissue recovery from an acute injury or a vigorous workout.

L-cysteine supplementation also has the potential to serve our bodies by boosting the immune system, maintaining heart and liver health, helping with muscle recovery after a hard workout and repairing soft tissue when an injury has occurred. It is also used to promote hair growth.

While supplementing this amino acid may have several health benefits, there are potential side effects.

L-cysteine Toxicity Levels

As with most supplements, overdosing with L-cysteine is a possibility and can cause unwanted side effects. Every drug or supplement has a known toxicity level that the body will likely react at when that level is met or surpassed. Toxicity levels are called Upper Tolerable Limits (ULs) and are set for each supplement including L-cysteine.

The normal safe range of L-cysteine Hydrochloride is 250 – 1500 mg per day. It is possible that a person may not experience adverse side effects if the well-tolerated amount of L-cysteine is taken.

The UL of L-cysteine is close to 7g per day; therefore, doses close to 7g and up may be toxic and cause harmful effects possibly needing medical attention and should never be taken in such high amounts.

Precautions

As with most supplements, including L-cysteine, allergic reactions are possible. Allergic reactions may be due to a hormone called homocysteine.

Homosysteine is a byproduct of L-cysteine and is released in the body in response to the presence of toxins. An allergic reaction may include heart arrhythmia, difficulty breathing, swelling of the face, runny nose, drowsiness, fever and headache.

If any of these symptoms are experienced when taking L-cysteine or N-Acetyl L-Cysteine, a medical practitioner should be notified.

Pregnancy is a very sensitive time and the consumption of any drug or supplement should be evaluated before taken. When a woman is pregnant, it is possible for most things she consumes to be transported across the placenta and affect the growth and development of the baby.

L-cysteine is currently listed as ‘possibly safe’ when taken by a woman when she is pregnant. It is known that L-cysteine does cross the placenta but there is no evidence currently that links it to any harmful side effects for mother and baby.

However, L-cysteine should only be taken by a pregnant mother when absolutely necessary since there is no evidence that consumption during pregnancy is beneficial. A physician should be contacted before taking L-cysteine when pregnant or breastfeeding.

Common L-Cysteine Side Effects

If taken in the normal range, most people are not likely to experience severe side effects when taking L-cysteine but the possibility is always present. Common side effects may include gastrointestinal discomfort such as bloating, gas and irritability.

When taking a supplement, we are giving are bodies a concentrated amount of a dry compound; therefore, it is good practice to take plenty of water with any supplement.

Other than GI discomfort, some side effects that may be experience when taking L-cysteine may include nausea, vomiting, diarrhea or constipation, body aches and cramps. Again, most of these side effects, when not severe, may be decreased when L-cysteine is taken with plenty of water.

Drug Interactions

Supplements containing L-cysteine may cause adverse interactions with other medications and supplements. L-cysteine has the ability to decrease inflammation, may aid in heart health and in some cases is given in conjunction with nitroglycerin to decrease symptoms of angina – also known as heart pain.

However, it is also possible for L-cysteine to block or increase the effects of nitroglycerin and therefore a physician should be consulted when they are taken together.

Other drug interactions that have been occasionally reported when supplementing with L-cysteine are those with ACE inhibitors, isosorbide, cyclophosphamide and charcoal (used to treat instances of overdose). All supplements should be taken with caution and one should avoid taking new supplements together in order to distinguish adverse reactions.

L-cysteine side effects are generally mild when it is taken within the safe dosage range. However, using too much can cause adverse reactions.

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