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Dietary supplement

L-Citrulline 500 mg Ingredients & Drug Interactions

by Source Naturals

Capsule Category: Amino Acid/protein
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

L-Citrulline 500 mg is a dietary supplement by Source Naturals with 1 active ingredient. Its ingredients are commonly taken for exercise performance, muscle soreness and fatigue, blood flow and circulation.Based on those ingredients, 178 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Citrulline. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of L-Citrulline 500 mg by Source Naturals

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: L-Citrulline, an amino acid that your body converts to another amino acid called L-arginine. The capsule also includes inactive ingredients — gelatin, microcrystalline cellulose, silica, and magnesium stearate — which are standard binders and fillers.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: supports exercise recovery energy and detoxification.
  • We looked for evidence on: Athletic performance, Muscle strength, exercise performance, muscle fatigue recovery.
  • The strongest evidence on file: L-citrulline is rated "Possibly Effective" for Athletic performance (Natural Medicines).
  • Also on file: L-citrulline is rated "Insufficient Reliable Evidence To Rate" for Muscle strength.

L-Citrulline is possibly effective for athletic performance. For sarcopenia (age-related muscle loss), the evidence suggests it's possibly ineffective.

For heart failure, cardiovascular disease, Reye syndrome, and diabetes, there isn't enough reliable evidence in the data we hold to rate whether it works.

The evidence, ingredient by ingredient L-citrulline

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-Citrulline is generally well tolerated in healthy adults, though long-term safety hasn't been fully studied. The most common side effects are gastrointestinal discomfort and heartburn.

There isn't enough safety data for use during pregnancy or breastfeeding, so it's best to avoid it if you're pregnant or nursing — talk with your doctor or pharmacist for personalized advice.

Side effects, ingredient by ingredient L-citrulline

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — L-citrulline.
  • The most serious interaction on file is rated Moderate.
  • For scale: 178 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check with your own doctor or pharmacist before taking this if you use blood pressure medications or PDE-5 inhibitors (erectile dysfunction drugs like Viagra or Cialis). Both can interact with L-Citrulline at moderate severity.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

L-Citrulline may help with athletic performance, but if you take blood pressure medications or erectile dysfunction drugs, you need to check with your own doctor or pharmacist first — the combination could lower your blood pressure too much. Pregnant or nursing?

Skip it until you've talked it over with your healthcare provider.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Mar 22, 2023.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about L-Citrulline 500 mg, straight from the product label.

Brand Source Naturals
Barcode (UPC) 021078020059
Net contents 120 Capsule(s)
Market status On market
Date entered into DSLD Mar 22, 2023
DSLD ID 273575
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for L-Citrulline 500 mg by Source Naturals, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
4 Capsule(s)
Maximum serving Sizes:
4 Capsule(s)
Servings per container
30
UPC/BARCODE
021078020059
IngredientAmount% DV
L-Citrulline2 Gram(s)--

Other ingredients: Gelatin, Microcrystalline Cellulose, Silica, Magnesium Stearate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
FDA Statement of Identity

Dietary Supplement

Formulation

Free form Supports exercise recovery energy and detoxification

Contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.

Suggested/Recommended/Usage/Directions

Suggested Use: 4 capsules three times daily.

Precautions

Warning: Consult your physician prior to using this product if you are pregnant, may become pregnant, breastfeeding, or if you are taking prescription medications for conditions such as heart disease or erectile dysfunction.

Not recommended for use following a heart attack.

Do not use if either tamper-evident seal is broken or missing.

Keep out of the reach of children.

Formula

L-Citrulline is a natural amino acid that supports sports performance and good health, while at the same time helping the liver detoxify. L-Citrulline helps the body rid itself of ammonia, a by-product of intense exercise. This clearing enables the body to recover after a workout, and it frees ATP energy for enhanced uses such as respiration and signal transduction.

Storage

Store in a cool, dry place.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Brand IP Statement(s)

Copyright SOURCE NATURALS, INC.

See for yourself

L-Citrulline 500 mg by Source Naturals label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in L-Citrulline 500 mg by Source Naturals

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size4 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

L-Citrulline

Interacts with
178 drugs
2 Gram(s) per serving

L-citrulline is an amino acid that the body turns into L-arginine to help make nitric oxide, which relaxes blood vessels and may improve blood flow. I...

L-Citrulline monograph & interactions

Other (inactive) ingredients: Gelatin, Microcrystalline Cellulose, Silica, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Citrulline 500 mg by Source Naturals Drug Interactions

Want to check YOUR meds against L-Citrulline 500 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
178Drugs
178 Moderate

Ingredients driving the most interactions

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Citrulline 500 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

L-Citrulline2 drug types · 178 drugs

Antihypertensive Drugs

Theoretically, concomitant use of L-citrulline with antihypertensive drugs might have additive effects and increase the chance of hypotension.
L-citrulline is converted to L-arginine, which can increase nitric oxide and cause vasodilation. However, a meta-analysis of 5 small clinical studies suggests that taking L-citrulline 3-6 grams daily for 1-8 weeks does not lower blood pressure when compared with control.

Likelihood Possible Evidence B
Phosphodiesterase-5 Inhibitors

Theoretically, concurrent use of phosphodiesterase-5 (PDE-5) inhibitors and L-citrulline might result in additive vasodilation.
L-citrulline is converted to L-arginine, which can increase nitric oxide and cause vasodilation. Theoretically, taking L-arginine with PDE-5 inhibitors might have additive vasodilatory and hypotensive effects. However, in studies evaluating the combined use of L-arginine and sildenafil for erectile dysfunction, hypotension was not reported.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for L-Citrulline 500 mg, from the product label.

Source Naturals

Name
Source Naturals, Inc.
Street Address
P. O. Box 2118
City
Santa Cruz
State
CA
ZipCode
95062
Web Address
www.sourcenaturals.com
Pharmacist Counseling Corner

L-Citrulline 500 mg by Source Naturals: Common Questions

Does L-Citrulline 500 mg by Source Naturals interact with any medications?
Yes. Based on its ingredients, L-Citrulline 500 mg has a known interaction with 178 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Citrulline 500 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
What does L-Citrulline actually do in my body?
Your body converts L-Citrulline to L-arginine, which increases nitric oxide and widens your blood vessels. That's why it's being studied for athletic performance and heart health.
Can I take this for muscle building?
The evidence shows L-Citrulline is possibly effective for athletic performance. For sarcopenia (age-related muscle loss), it's rated possibly ineffective — so it's not a proven tool for that specific problem.
What are the most common side effects?
Gastrointestinal discomfort and heartburn are the most common complaints. A small number of people reported cough, and general stomach upset has been noted.
Is it safe to take if I'm pregnant or breastfeeding?
There isn't enough safety data either way. It's best to avoid it during pregnancy and breastfeeding — talk with your doctor or pharmacist about whether it's right for your situation.
How long has this supplement been studied for safety?
L-Citrulline is generally well tolerated in healthy adults, but long-term safety hasn't been fully studied. We just don't have enough long-term data yet.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if L-Citrulline 500 mg is safe with your meds?

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Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

L-Citrulline 500 mg label
Sources

Sources & How We Checked

L-Citrulline 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 8 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

L-citrulline 8 references
  1. Cheng JW, Balwin SN. L-arginine in the management of cardiovascular diseases. Ann Pharmacother 2001;35:755-64. PubMed
  2. Schwedhelm E, Maas R, Freese R, et al. Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism. Br J Clin Pharmacol 2008;65:51-9. PubMed
  3. Romero MJ, Platt DH, Caldwell RB, Caldwell RW. Therapeutic use of citrulline in cardiovascular disease. Cardiovasc Drug Rev 2006;24:275-90. PubMed
  4. Balderas-Munoz K, Castillo-Martínez L, Orea-Tejeda A, et al. Improvement of ventricular function in systolic heart failure patients with oral L-citrulline supplementation. Cardiol J 2012;19:612-7. PubMed
  5. Sharif Kashani B, Tahmaseb Pour P, Malekmohammad M, et al. Oral l-citrulline malate in patients with idiopathic pulmonary arterial hypertension and Eisenmenger Syndrome: a clinical trial. J Cardiol 2014;64:231-5. PubMed
  6. Pérez-Guisado J, Jakeman PM. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res 2010;24:1215-22. PubMed
  7. Mirenayat MS, Moradi S, Mohammadi H, Rouhani MH. Effect of L-citrulline supplementation on blood pressure: a systematic review and meta-analysis of clinical trials. Curr Hypertens Rep. 2018;20(11):98. PubMed
  8. Xu Z, Liu C, Liu S, Zhou Z. Comparison of efficacy and safety of daily oral L-arginine and PDE5Is alone or combination in treating erectile dysfunction: A systematic review and meta-analysis of randomised controlled trials. Andrologia. 2021:e14007. PubMed

See these in context on the L-citrulline monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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