Drug & supplement interaction

L-arginine + Testosterone

Testosterone brand names: Intrinsa, Testim, Androgel, Andropatch, Testogel, and others.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

L-arginine has a minor interaction with Testosterone. Theoretically, concomitant use of L-arginine and testosterone might have additive effects.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

L-arginine and Testosterone

Here is the interaction we found between these two, with the evidence behind it.

Minor

TESTOSTERONE

Theoretically, concomitant use of L-arginine and testosterone might have additive effects.
In clinical research, L-arginine increases the level of testosterone in male patients with erectile dysfunction. The clinical significance of this finding is unclear.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: this is a very mild, mostly theoretical pairing. Some research has shown that L-arginine can nudge testosterone levels up a little in men with erectile dysfunction. So the thought is that adding it on top of your prescribed testosterone (like AndroGel, Testim, or Nebido) could have a slight additive effect, meaning your levels might run a touch higher than expected.

In real life, the clinical importance of this is unclear, and we don't have strong evidence that it causes problems. Testosterone is dosed and monitored with blood tests, so if anything shifted, your doctor would catch it. Since your levels are tracked carefully, it's still worth telling your pharmacist or doctor before adding L-arginine so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. El Taieb M, Hegazy E, Ibrahim A. Daily oral l-arginine plus tadalafil in diabetic patients with erectile dysfunction: A double-blinded, randomized, controlled clinical trial. J Sex Med. 2019;16(9):1390-1397.
  2. Abu El-Hamd M, Hegazy EM. Comparison of the clinical efficacy of daily use of L-arginine, tadalafil and combined L-arginine with tadalafil in the treatment of elderly patients with erectile dysfunction. Andrologia. 2020;52(7):e13640. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

L-arginine Also Interacts With Other Medications

L-arginine has 395 moderate, 7 minor known drug interactions in our database — the Testosterone one above is one of them. If you take anything else, check it against the full list below.

Moderate 395 Minor 7 No known interaction 2,428 (incl. Testosterone)
Taking anything else?

Check Another of Your Medications Against L-arginine

Covers the 2,830 medications we’ve checked against L-arginine. Pick one to open its full report.

From our Q&A

Questions About L-arginine or Testosterone

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers L-arginine or Testosterone, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Testosterone

This page covers L-arginine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Testosterone page lists 170 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Beer (major), Grapefruit (major), Siberian Cocklebur (major), St. John's Wort (major) and Wine (major).

By severity: 5 major · 129 moderate · 36 minor.

From our pharmacist’s overview on the Testosterone page

“The supplement list for testosterone therapy (Androgel, Testim, Nebido, and others) deserves real attention, mainly because five of its 170 entries are rated major and four of those are everyday items: grapefruit, St. John's wort, and alcohol in the form of beer or wine.”

Reviewed by 2 · Jul 18, 2026

Open the Testosterone interaction page

One more smart check

Taking L-arginine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 26 real supplement products containing L-arginine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides L-arginine. Your product may carry other ingredients that interact with Testosterone too, on top of L-arginine — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where L-arginine and Testosterone Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement L-arginine
Steady interest

#831 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Testosterone
Top 1%

#15 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About L-arginine

What is L-arginine?

L-arginine
  • High blood pressure
  • Erectile dysfunction
  • Athletic performance
  • Chest pain (angina)
  • Improving blood flow

L-arginine is an amino acid that the body uses to make nitric oxide, a substance that helps blood vessels relax and widen. It is popularly used for blood pressure, erectile dysfunction, and exercise, but the evidence is mixed and stronger for some uses than others. It is generally well tolerated in healthy adults, but talk with a pharmacist or doctor before using it, especially if you have heart problems or take other medicines.

Read the full L-arginine monograph & all interactions
Medication

About Testosterone

What Is Testosterone Used For?

Brand names: Intrinsa, Testim, Androgel, Andropatch, Testogel, Nebido, Delatestryl, Natesto, Vogelxo

Testosterone replacement therapy is used in adult males whose bodies do not produce enough of their own testosterone. This includes primary hypogonadism — where the testes themselves fail due to causes such as Klinefelter's syndrome, injury, chemotherapy, or surgical removal — and hypogonadotropic hypogonadism, where the brain's signaling system (the hypothalamus or pituitary gland) fails to trigger testosterone production.

Testopel (subcutaneous pellets) may also be used to stimulate puberty in carefully selected males with clearly delayed puberty. The safety and efficacy of testosterone for age-related (late-onset) hypogonadism have not been established for most products, including AndroGel, Testim, Jatenzo, Kyzatrex, Natesto, Depo-Testosterone, Testosterone Cypionate, and Xyosted.

See full Testosterone drug information
Keep checking

Other Drugs & L-arginine

Browse every other medication we’ve checked against L-arginine — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
395Moderate
7Minor
2,427No known interaction
395 Moderate 7 Minor 2,427 No interaction
Moderate

395 interactions

Showing 60 of 395 moderate interactions — see all 395 on the L-arginine page.

Minor

7 interactions

No interaction 2,427 drugs checked — show the list

We also checked L-arginine against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,427 medications checked with no known interaction — see the full L-arginine list.

See the full L-arginine interactions page
See every supplement checked against Testosterone, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

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

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

Keep exploring
L-arginine monograph › Uses, safety, and every drug interaction in one place Testosterone supplement interactions › Every supplement checked against Testosterone, ranked by severity Testosterone drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking L-arginine and Testosterone Together: Common Questions

Can you take L-arginine with Testosterone?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the L-arginine and Testosterone interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Testosterone and L-arginine?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.