L-Arginine Side Effects and Interactions

What L-arginine side effects should I watch out for?

L-arginine is an amino acid found in foods such as red meat. It is used by the body to build protein structures. As it is found in nature, side effects are not expected to be significant.

However, used as a supplement, higher doses are usually taken than would be found from just eating meat alone. The side effects listed below have been seen in research studies. The side effects reported by volunteers in the studies are generally mild.

Bookmark and Share  

Side Effects, Toxicity and Warnings

Common side effects include: diarrhea, stomach pain and bloating, nausea, vomiting and lowered blood pressure (leading to dizziness and fatigue).

Allergic response is uncommon but it could cause asthma attack, skin rash or swelling.

Safety - When used in research studies for up to 3 months for treating poor circulation and erectile dysfunction, L-arginine was shown to be safe.

Pregnancy & Lactation - It is probably safe to use during pregnancy in appropriate doses. There is no information on using L-arginine during lactation.

To avoid L-arginine side effects, always start with the lowest suggested dose and then increase gradually over several days or weeks.

Common Drug & Health Condition Interactions

Myocardial Infarction (MI) / Heart Attack - caution

Using L-arginine after a patient has suffered a heart attack showed no benefit.

The researchers advised that patients who had a recent heart attack to avoid taking this supplement. One study showed that subjects taking 3 grams of L-arginine daily for 6 months cause 6 patients (8.6%) to die compared to patients not taking L-arginine supplement.

High blood pressure medications - theoretical / caution

As L-arginine can lower blood pressure, combining it with prescription blood pressure medication can cause further drop in blood pressure.

Monitor your blood pressure when you start or stop this supplement. If you are currently on prescription medication for controlling blood pressure, you may need to reduce your dosage. Consult your healthcare professional.

Viagra (sildenafil) / Levitra (vardenafil) - theoretical / caution

As L-arginine and Viagra (sildenafil) can both lower blood pressure, combining the two may cause additional drop in blood pressure.

Monitor your blood pressure closing when you are starting or stopping this medication while on Viagra or Levitra. This will ensure you find out how your body respond to this supplement.

Cancer - theoretical / caution

While research suggest that L-arginine helps in some forms of cancer, other research showed that nitric oxide (made from L-arginine) can speed up the growth or the spread of cancer cells.

More studies in humans will be needed before we can get accurate results.

Dementia / Alzheimer's Disease (AD) - theoretical

Current research reported that the brains of patients with Alzheimer's disease (AD) contain higher levels of L-arginine. Also the formation of NO has been suggested to contribute to the condition leading to AD.

We don't know whether AD causes an increase in L-arginine in the brain or that high levels of L-arginine causes AD.

Herpes Virus Infection / Cold Sores - theoretical

L-arginine might be needed for the virus to multiple. Avoid taking this amino acid when the herpes virus are actively multiplying.

Facts on L-Arginine

Read this review on L-arginine befor taking it...


Benefits of L Arginine and Discussions on Research Studies Done

Find out results from some of the research studies done on benefits of L-argininefor treating various health conditions...


Recommended Dosage to Use

Get detailed information on L-Arginine Dosage to use for treating various health conditions in this detail article...

Related Articles and Resources on L-Arginine Side Effects


Return to L-Arginine

References for L-Arginine Side Effects

Updated:June 20,2010