L-arginine is a type of amino acid which can be sourced from foods. This substance has the capabilities to boost your hormonal health as well as promote insulin balance. L-arginine gets transformed into nitric oxide, a substance which enables uniform flow of blood to all parts of your body. Owing to this unique property, it is widely used for treating male impotence or erectile dysfunction, angina caused by shrinking of blood vessels, hypertension, etc. L-arginine can be sourced from several animal-based foods such as fish, poultry, red meats and milk-based food products. This substance is also capable of triggering a few side effects. It is strongly recommended to know the side effects of l-arginine to ensure safe consumption.

L-arginine is an amino acid. Amino acids are closely associated with the metabolism of proteins. L-arginine is produced when proteins are processed and broken down. So, it offers very little surprise to know it is present in sizable quantities in foods rich in proteins. Such protein-rich foods include whole grains, beans, soy, fish, meat, poultry as well as dairy-based foods. A few types of nuts and seeds such as walnuts, peanuts, etc. are also known to contain this substance. You can take it as a dietary supplement, which can be consumed by mouth (orally) or by topically applying it on your body. This substance is categorized as an essential substance during times of pregnancy, early childhood, during the onset of acute ailments as well as injuries.

L-arginine plays a key role in the production of nitric oxide; this oxide serves as a stimulant to several essential activities. Such activities include functioning of your cells (especially, cellular mitochondria), flow of blood as well as intercellular signalling, to name a few. L-arginine is also used for widening of blood vessels. It is hence taken for medical conditions such as cardiac ailments or disorders, angina and high blood pressure (hypertension). However, if you are already taking medicines or undergoing treatment for hypertension, it is highly recommended to talk to your physician before taking l-arginine – i.e., from either naturally available foods or through dietary supplements.

This substance is also essential for the production of immunity-boosting T-cells or a few other types of white cells in your blood. As an added advantage, l-arginine helps remove waste – such as ammonia – from your body. It thus helps rectify problems associated with synthesis and breakdown of waste items such as urea. Last but not the least; l-arginine can help exert needful control on blood-sugar levels, especially among people living with diabetes-mellitus.

Dosage of l-arginine

The intake of l-arginine is generally considered safe. The daily dosage of this substance can vary based on the underlying need. Most doses are of short term nature only. For instance, men who are unable to maintain an erection of their penis are advised to take as low as only 3 grams each day for a very short term. Those with hypertension (i.e., high blood pressure) are administered dosages ranging from 10 to 20 grams on a daily basis; the duration for such treatment for hypertension may range from 1 month to 5 months.

L-arginine is also administered to treat a pregnancy related complication known as preeclampsia; this condition shows up with episodes of high blood pressure and a likely damage of key organs such as kidneys or liver. In such instances, the dose is usually about 4 grams each day, again for a short term period of 2 to 3 months. In general, doses of less than 8 to 9 grams per day are known to be safe, and are unlikely to trigger abdominal discomforts such as gas formation or bloating, pain, indigestion or nausea. For treating angina or similar type of pain in chest, a dosage of upto 5 grams on a daily basis is prescribed for upto 4 weeks.

L-arginine can also be co-administered with non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen in the treatment of acute and chronic spells of headache. In some instances, it is co-administered with fellow-amino acids for people living with infections such as HIV AIDS; it is used in the medication plan for treating loss of bodyweight in such patients. In very rare cases, it is used along with chemotherapeutic drugs administered for the medical treatment of cancers. It is also used in post-surgical rehab to reduce the duration of recovery as well as decrease the dependence on drugs among patients soon after a surgery.

Side effects of l-arginine

The most commonly experienced side effects of l-arginine are bloating or formation of gas, indigestion, respiratory problems, abdominal discomforts such as nausea, pain in lower abdomen, flatulence, etc. It is hence not a good practice to take l-arginine if you have respiratory disorders such as bronchitis, asthma, etc. The treating doctor may advise you to avoid its intake if you had recently experienced a cardiac arrest or heart attack. Intake of this substance in such instances may lead to near-fatal or at times, even fatal outcomes.

In general, side effects may show up if you take l-arginine in doses more than 8 grams or more per day. However, short term intake of larger doses (i.e., more than 20 grams per day) have been proven to be safe. Hence, you are advised to be conscious of the dosage levels if you are prescribed to take it for a longer time span – say, for 9 months or more.

One other common side effect of l-arginine is gout. This is an arthritic condition resulting in the inflammation of joints and stiffening of tissues present near the swollen joints. You may experience acute spells of pain during its onset. Those who have a medical history of liver damage or cirrhosis, renal dysfunction, hypotension (lower levels of blood pressure), etc. are not recommended to take this substance. Some people may have congenital disorders which may impair the processing of substances like l-arginine; such people are also not advised to take this amino acid. Large dosage forms of l-arginine can result in increased production of acids in stomach. Owing to this, it may lead to ulcers, acid reflux and other problems in your digestive tract. If taken as a shot, it may – at times – cause allergic reactions such as vomiting, nausea and digestive disorders.

Minor side effects

A few of the side effects of l-arginine may not need medical attention or added support. These signs may show up only to disappear as soon as your body gets used to the dietary supplement of l-arginine. Such minor side effects include headaches, numbness, tingling sensation, vomiting and other abdominal discomforts. However, if any of these effects persist for long, you are advised to talk to your treating doctor or a pharmacist without any further delay. You also need to note that the side effects listed above do not constitute a complete or full list. So, if you are experiencing any allergic reactions or side effects which are not listed above, you are advised to take needful medical help immediately.

Serious side effects

A few serious side effects – some of them may not be fully attributed to l-arginine though – may require medical help or counsel. Such serious side effects are very rare in nature. These include inflammation (especially of your limbs), discoloration or formation of red patches on your skin, difficulties in swallowing food, traces of blood in urine, long spells of weariness or fatigue, etc. It is not a good practice to wait for these signs to disappear on their own. As soon as you spot any of these rare signs, you are advised to consult your treating physician or talk to your pharmacist without wasting time.


An overdose of l-arginine is likely to lead to more adverse side effects. These include twitching of muscles, spells of drowsiness, being in a confused state of mind, faster rate of respiration, cramping of abdominal muscles, etc. If you experience any of these acute or severe side effects, you need to take medical attention on an emergency basis. If you are a resident of US, you need to call the food and drug administration’s (FDA) helpline or get in touch with 911 without any delay. If you are living in Canada, you are advised to contact a local poison control center.

Safety precautions

You are advised to store l-arginine in a dry and cool place. Exposure of supplements to moisture can impair the properties of the drug. L-arginine is likely to interact with a few categories of medications. These include water pills or diuretics, drugs taken to enhance the flow of blood, diabetic drugs, blood thinners such as warfarin and drugs taken to treat male impotence or erectile dysfunction. The risks of interactions between l-arginine supplements and anti-hypertensive drugs such as losartan, captopril or valsartan are more pronounced. You are hence advised to talk to your treating physician or pharmacist prior to co-administering these drugs.

If you take l-arginine with medications which increase the blood flow, you are more likely to run the risks of drowsiness or dizziness; for example, drugs such as isosorbide, nitro-glycerin, etc. are known to increase blood flow. Also, men with sexual problems such as impotence or erectile dysfunction may be taking drugs like sildenafil citrate (Viagra). Such ED drugs can reduce your blood pressure levels. Hence, intake of l-arginine along with ED medications is not recommended.

Women who are pregnant may take it if the need arises; however, its doses are prescribed only for a very short term. In case of children, larger doses are not considered as safe. Larger doses may lead to outcomes such as death among teens and children. If you have prior medical conditions such as herpes (especially, genital herpes) or cold sores, you are advised to stay away from l-arginine. This is because of its ability to aggravate the spread and intensity of such viral infections. If you are going to undergo a surgical intervention, you are advised to discontinue the intake of l-arginine at least a few weeks prior to your surgery. This is because of the risks of lower blood pressure and such risks may intervene with blood pressure readings during or soon after your surgery.

In general, the best way to avoid an overconsumption of l-arginine is by sourcing it from naturally grown foods. The good news is – food sources have minor traces of this substance; hence, the risks of a likely overdose are very rare. However, foods may not be able to fully support your need for l-arginine. Your doctor may hence prescribe safer alternatives such as supplements of l-arginine. As risks of overdose are high with dietary supplements, you are expected to strictly adhere to the low dose prescriptions given by your physician.

In sum, the most common side effects of l-arginine are pain in abdomen, formation of gas, bloating, indigestion, hypotension (decreased levels of blood pressure), internal swelling, respiratory problems, gout (an autoimmune condition that affects your joints and the tissues near them), etc. If your medical history has any of these conditions – especially, respiratory disorders like asthma or bronchitis and blood pressure related disorders such as hypertension or hypotension – you are advised to talk to your treating doctor or the pharmacist about these pre-existing conditions.

Leave a Reply