L-Arginine Benefits, Uses & Side Effects (2025)

What are the forms and brand names of l-arginine?

L-arginine is available in two forms: fluid injected inside of your vein through an IV (intravenously) or taken by mouth (capsules or tablets).

The brand name for IV-form l-arginine is R-Gene 10 ®.

There are several types of l-arginine supplements available over the counter. Talk with your healthcare provider before starting l-arginine supplements.

What dosage strengths does l-arginine come in?

Dosage varies for each brand of l-arginine and the specifications are marked on the label. The average dosage of l-arginine is between 6 grams to a maximum of 30 grams per day. The daily dose is normally divided into three smaller doses per day that won’t exceed the maximum dosage. Do not take more than the maximum dosage of l-arginine.

Check with your healthcare provider before taking over-the-counter l-arginine supplements to see if they are right for you.

If your provider prescribes treatment with l-arginine via an IV, they will administer the correct dosage according to your age, the reason for treatment and other factors.

How should I take l-arginine?

You can take l-arginine by incorporating foods that are high in l-arginine into your diet. Foods that are high in protein are great ways to increase your l-arginine levels.

If you aren’t getting enough l-arginine through your diet, your provider might suggest taking over-the-counter l-arginine supplements. You can take l-arginine supplements by mouth, following the dosage on the label of the supplement and the recommendation from your provider.

If you need to take l-arginine via IV, your provider will monitor and administer the treatment in a healthcare facility.

How long does it take for l-arginine to work?

Depending on your reason for taking l-arginine and which type of amino acid you need, it takes a minimum of 24-hours for the l-arginine to absorb into your body. In some cases, to see the full effects of regular l-arginine treatment, it could take up to three months.

What are the side effects of l-arginine?

Side effects are possible with l-arginine treatment and could include:

• Bloating.
• Diarrhea.
• Dizziness.
• Nausea or vomiting.

Life-threatening side effects include:

• Allergic reaction (hives, itching or rash).
• Difficulty breathing or a tight feeling in your chest.
• Heart failure.

If you experience any side effects, reach out to your healthcare provider or visit your nearest emergency room immediately.

Are there any serious interactions with l-arginine?

L-arginine interacts with other medicines. Don’t take l-arginine without first talking to your provider about medicines you currently take. L-arginine interacts with the following:

L-arginine can cause interactions if you have certain health conditions. You shouldn’t take l-arginine if you:

• Recently had a heart attack.
• Have a guanidinoacetate methyltransferase deficiency.
• Are a child under 16 years of age, are pregnant or breastfeeding or are an adult older than 65 years of age without approval from your provider.

Always check with your provider before starting l-arginine supplements or treatment.

Can I take l-arginine if I’m pregnant or breastfeeding?

Don’t take l-arginine supplements if you’re pregnant or breastfeeding without first talking with your provider to see if the amino acid is right for you. L-arginine could cause unexpected complications during pregnancy, and there is not enough research to specify whether or not l-arginine supplements pass through breastmilk.

What should I tell my healthcare provider before starting l-arginine?

Talk to your healthcare provider about the medicines, vitamins and supplements that you’re currently taking before starting l-arginine. You’ll also want to discuss your health history with your provider, especially if you recently had a heart attack, are pregnant or breastfeeding or if you have an underlying medical condition. Your provider will assess your symptoms and let you know if it is safe to start taking l-arginine.