Cysteine (L-cysteine) is a non-essential amino acid, meaning it
can be synthesised by the body (from the amino acid methionine).
Cysteine is an essential amino acid in infants, which may explain
the high Cysteine content of human breast milk.
Cysteine is a sulphur containing amino acid and as such is an
important component of the protective antioxidant systems of the
body. Antioxidants are responsible for 'mopping up' damaging
substances called free radicals, produced during normal metabolic
processes and as a result of external insults such as chemicals or
radiation. Free radicals are thought to be linked to the ageing
process and chronic diseases such as heart disease and
Cysteine is rarely taken as a supplement. A substance called
N-acetylcysteine (a precursor for Cysteine) is the most frequently
used form of this amino acid.
Cysteine has been investigated in relation to the following medical
Peptic Ulceration and Gastric
Studies have shown that the DL form of Cysteine taken orally can
help stimulate the healing of peptic ulcers caused by aspirin and
similar drugs (NSAIDs), protect against the complications of
bleeding from gastritis and reduce the likelihood of duodenal
ulceration recurring. Cysteine may help strengthen the protective
lining of the stomach and intestines.
Poisoning and Detoxification
The ability of Cysteine to boost the antioxidant defences of the
body (in particular those found in the liver) make it an important
detoxifying agent. N-acetyl cysteine is the medical treatment for
paracetamol (paracetamol) overdose and has been studied in animals
as a possible treatment for heavy metal toxicity (metals such as
arsenic, cadmium, copper, gold, lead, mercury and silver).
Cysteine may have some benefit in certain forms of respiratory
disease due to both its antioxidant and mucolytic (breaks up mucus)
activities. Studies on people with chronic bronchitis, severe
airways obstruction and cystic fibrosis taking N-acetyl cysteine
showed a very small benefit, with less frequent exacerbations of
their condition. Improvements were noted in severity of cough, ease
in bringing up Mucus and fatigue of the respiratory muscles. Most
benefit was obtained by people with a condition known as fibrosing
alveolitis, where free radical damage is thought to be a major part
of the disorder.
People with HIV have been found to have lower levels of Cysteine
and glutathione. A few studies suggest that N-acetyl cysteine, if
given early in the course of the disease, may slow progression of
HIV to AIDS. This may be due to an immune enhancing effect of
Cancer and Chemoprevention
While studies have not yet been done on humans, it is thought that
N-acetyl cysteine may help prevent the development of cancerous
cells as well as protecting normal cells (but not cancerous cells)
from the toxic effects of chemotherapy and radiotherapy. Studies
looked at cancers of the lung, skin, head and neck, breast and
liver. At the time of writing, studies in this area are still
Several small clinical studies have shown the antioxidant
properties of N-Acetylcysteine (NAC) may be of assistance in the
management of heart disease. Oral NAC lowered blood levels of
homocysteine and lipoprotein(A), substances associated with a
higher risk of developing cardiovascular disease. NAC also improved
the vasodilatory activity of the anti-angina drug nitroglycerine,
suggesting a benefit for people with angina or narrowing of the
arteries supplying oxygen to their heart.
NAC may help prevent changes caused by smoking in cells lining the
respiratory passage. Other studies show it can also help bring
function of certain immune cells in the lungs back towards normal
Ask your Pharmacist for advice.
1) Protein needs of active people are different from those of
inactive people. Recommended protein intake for healthy people
ranges between 0.8 and 1.6-1.8 grams of protein per kilogram per
day. Most people on a Western diet get more protein than is
required for maintenance of normal metabolic processes, although
some elderly people may be at risk of protein malnutrition because
of inadequate dietary intake.
2) Protein requirements may be higher in athletes, children,
pregnant women and people with chronic disease, injury, infection
3) Check with your Pharmacist before taking any protein
supplements. Some people may have health conditions (e.g. kidney
disease) which require low protein diets.
4) A range of protein supplements are available for athletes and
bodybuilders. Your Pharmacist can help you choose a product
appropriate for your needs.
Chicken, beef, fish, eggs, liver, sardines, cottage cheese,
- Cysteine is considered to be of low toxicity, even in high
doses. Daily use in healthy individuals is not recommended however,
to avoid conversion of excess Cysteine to damaging free radicals.
Daily use should by reserved for those with a condition leading to
high levels of oxidant stress. Ask your Doctor for more
- The safety of Cysteine in pregnancy is unknown, although N
Acetylcysteine has been used in pregnant women with no reports of
harm. When pregnant, always use medications according to your
- High oral doses of N-Acetylcysteine have been associated with
nausea, vomiting and other gastrointestinal disturbances. A small
number of individuals may be allergic to NAC. Symptoms include
rash, itching, swelling, difficulty breathing and changes in blood
Ask your Naturopath for advice. 1) Protein needs of active
people are different from those of inactive people. Recommended
protein intake for healthy people ranges between 0.8 and 1.6-1.8
grams of protein per kilogram per dayLemon PW. Beyond the zone:
protein needs of active individuals. J Am Coll Nutr.2000 Oct;19(5
Suppl):513S-521S.. Most people on a Western diet get more protein
than is required for maintenance of normal metabolic processes,
although some elderly people may be at risk of protein
malnutritionClarke DM. Undereating and undernutrition in old age:
integrating bio-psychosocial aspects. Age and Ageing, July 1998.
because of inadequate dietary intake. 2) Protein requirements may
be higher in athletes,Lemon PW. Beyond the zone: protein needs of
active individuals. J Am Coll Nutr.2000 Oct;19(5 Suppl):513S-521S.
children, pregnant women and people with chronic disease, injury,
infection or diabetesGarrow JS, et al.eds. Human Nutrition
and Dietetics.9thed.New York: Churchill Livingstone, 1998.. 3)
Check with your Physician before taking any protein supplements.
Some people may have health conditions (e.g. kidney disease)
which require low protein diets. 4) A range of protein
supplements are available for athletes and bodybuilders. Your
Naturopath can help you choose a product appropriate for your
THIS IS NOT DIAGNOSTIC INFORMATION. STAY ON PRESCRIBED MEDICINES.
(C) 2008 HEALTHPOINT TECHNOLOGIES.
- Australia's #1 Online Pharmacy
- Lowest Prices Guaranteed
- Safe, Secure and Trusted
- 100% Australian - Since 1999
- Over 500,000 Happy Customers
- Over 90% Shipped Next Day
- FREE SHIPPING On Orders Over $99*