Drug & supplement interaction

Testolone + Diltiazem

Diltiazem brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Testolone and Diltiazem in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Testolone and Diltiazem

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Diltiazem and Testolone in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Testolone safety at a glance

Testolone overall Avoid Testolone is an unapproved experimental drug with reported serious risks and should not be used.
Pregnancy Possibly Unsafe When used orally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androgen receptor modul... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androgen receptor modul... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Diltiazem and Testolone? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Diltiazem

Interactions in our licensed database are recorded against drug classes, not just single drug names. Diltiazem is filed under 9 classifications — including calcium channel blockers, cytochrome p450 1a2 (cyp1a2) inhibitors, cytochrome p450 3a4 (cyp3a4) inhibitors. Testolone has documented interactions with 1 drug class — the most serious being hepatotoxic drugs (moderate) — and none of Diltiazem’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Testolone Does Interact With Other Medications

Testolone has 370 moderate known drug interactions in our database — Diltiazem isn’t one of them. If you take anything else, check it against the full list below.

Moderate 370 No known interaction 2,460 (incl. Diltiazem)
Taking anything else?

Check Another of Your Medications Against Testolone

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

What to actually watch for

No Interaction Found — But Data Suggests Testolone and Diltiazem May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Shortness of breath Worth acting on reported in 9.6% of FDA reports for Diltiazem Additional detail

    Testolone

    “Acute myocarditis presumably associated with testolone has been reported in a 32-year-old male who used the product for athletic performance enhancement. The patient presented with shortness of breath and a mild fever, with elevations in troponin I, B-type natriuretic peptide, erythrocyte sedimentation rate, C-reactive protein, and D-dimer and received treatment with aspirin, atorvastatin, carvedilol, and furosemide,…”

    Testolone · Natural Medicines adverse-effect record, reported in athletic performance.

    5 sources cited
    1. 108161. Padappayil RP, Chandini Arjun A, Vivar Acosta J, Ghali W, Mughal MS. Acute myocarditis from the use of selective androgen receptor modulator (SARM) RAD-140 (Testolone). Cureus. 2022;14(1):e21663. PubMed
    2. 94879. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
    3. 94880. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
    4. 94881. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017
    5. 108159. LoRusso P, Hamilton E, Ma C, et al. A first-in-human phase 1 study of a novel selective androgen receptor modulator (SARM), RAD140, in ER+/HER2- metastatic breast cancer. Clin Breast Cancer 2022;22(1):67-77. PubMed

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A fast or pounding heartbeat / Fever Additional detail

    Testolone

    Recorded for Testolone in the same Natural Medicines adverse-effect record shown under Shortness of breath above.

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed ›

  • Reduced appetite / Vomiting Additional detail

    Testolone

    “Orally, vomiting and decreased appetite were reported to be some of the most common adverse effects in a dose escalation study of testolone 50-150 mg daily for about 8 weeks.”

    Testolone · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    1 source cited
    1. 108159. LoRusso P, Hamilton E, Ma C, et al. A first-in-human phase 1 study of a novel selective androgen receptor modulator (SARM), RAD140, in ER+/HER2- metastatic breast cancer. Clin Breast Cancer 2022;22(1):67-77. PubMed

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed ›

  • Itching / Diarrhea reported in 6.1% of FDA reports for Diltiazem Additional detail

    Testolone

    “A dose escalation study of testolone 50-150 mg daily for about 8 weeks found that the most common treatment-emergent adverse events included moderate elevations in aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin.”

    Testolone · Natural Medicines adverse-effect record, reported in diarrhea.

    5 sources cited
    1. 108159. LoRusso P, Hamilton E, Ma C, et al. A first-in-human phase 1 study of a novel selective androgen receptor modulator (SARM), RAD140, in ER+/HER2- metastatic breast cancer. Clin Breast Cancer 2022;22(1):67-77. PubMed
    2. 108160. Barbara M, Dhingra S, Mindikoglu AL. Drug-induced liver injury associated with alpha bolic (RAD-140) and alpha elite (RAD-140 and LGD-4033). ACG Case Rep J 2020;7(6):e00409. PubMed
    3. 94879. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
    4. 94880. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
    5. 94881. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Testolone but not commonly for Diltiazem: liver problems, a heart attack, weight loss and weight gain.

Effects for Diltiazem come from the ADVERSE REACTIONS section of its FDA label; effects for Testolone come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 34,400 voluntary FDA FAERS reports for Diltiazem that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Testolone in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selective androgen receptor modulators (SARMs) are dangerous. Avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Testolone or Diltiazem

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Testolone or Diltiazem, 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 Diltiazem

This page covers Testolone only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem page lists 260 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Coleus (major) and Grapefruit (major).

By severity: 7 major · 214 moderate · 39 minor.

From our pharmacist’s overview on the Diltiazem page

“Someone on diltiazem (Cardizem, Tiazac) is usually managing blood pressure, angina, or a fast heart rhythm, so this list deserves genuine care. Seven of the 260 ingredients on file carry a major rating, and two of those are things people actually buy: grapefruit, which blocks the enzyme that clears diltiazem and can push its blood leve…”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem interaction page

One more smart check

Taking Testolone as Part of a Dietary Supplement Product? Check It for Interactions

We hold 9 real supplement products containing Testolone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Testolone. Even though Testolone itself has no known interaction with Diltiazem, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Testolone and Diltiazem 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 Testolone
Steady interest

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

29 days ago today
Medication Diltiazem
Top 25%

#303 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Testolone reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Testolone and Diltiazem records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Testolone

What is Testolone?

  • Muscle building
  • Athletic performance and bodybuilding
  • Strength gains
  • Body recomposition (fat loss with muscle gain)

Testolone (RAD-140) is a synthetic experimental drug called a selective androgen receptor modulator (SARM), not a dietary supplement or herb, and it is not approved or proven safe for human use. It is illegally sold for muscle building, has been linked to serious harms including liver injury, and is banned in sports — it should not be taken outside of supervised clinical research.

Synthetic compound (not a plant); supplied as a chemical powder or liquid · Capsules, tablets, liquids, and powders sold as 'research chemicals'

An interaction check asks whether these two react with each other — it does not ask whether Testolone is a good idea for someone in your situation. Here is what our Testolone record says about it on its own.

Testolone: dosing

There is no established safe or approved dose of Testolone. It has not gone through the testing needed to set safe dosing guidelines for people.Doses listed on illegally sold products are not verified, and the actual content of these products is often unreliable. For these reasons, we do not provide dosing information.The safest choice is not to use Testolone.

From our Testolone monograph — the full record covers uses, side effects and every documented interaction.

Read the full Testolone monograph & all interactions
Medication

About Diltiazem

What Is Diltiazem Used For?

Brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, Diltiaz XT, Diltiaz CD, Dilacor, Diltiaz, Cardizem LA, Dilacor XR, Cartia XT, Tiamate, Adizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Dilcardia SR, Dilzem SR, Dilzem XL, Slozem, Tildiem LA, Tildiem Retard, Viazem XL, Zemtard 120XL, Zemtard 180XL, Zemtard 240XL, Zemtard 300XL

Oral extended-release forms of diltiazem — including Matzim LA, Cardizem LA, Cartia, Cartia XT, Tiadylt ER, and various generic capsules and tablets — are used to treat high blood pressure (hypertension) and chronic stable angina (chest pain brought on by activity). Some capsule formulations, including Cartia, Cartia XT, and certain generics, are also approved for angina due to coronary artery spasm (sudden chest pain caused by a sudden tightening of a coronary artery).

Injectable forms of diltiazem are used in hospital settings to temporarily slow a dangerously fast heart rate in atrial fibrillation or atrial flutter (rapid, irregular heart rhythms), and to restore a normal heart rhythm in paroxysmal supraventricular tachycardia (PSVT) — sudden episodes of a very fast but regular heartbeat originating above the heart's lower chambers.

Most-Reported Side Effects for Diltiazem

From FAERS, the FDA’s public side-effect reporting system (34,400 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 3,309 reports
Fatigue 2,733 reports
Nausea 2,454 reports
Dizziness 2,174 reports
Diarrhea 2,113 reports
See full Diltiazem drug information
Keep checking

Other Drugs & Testolone

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

0Major
370Moderate
0Minor
2,459No known interaction
370 Moderate 2,459 No interaction
Moderate

370 interactions

Showing 60 of 370 moderate interactions — see all 370 on the Testolone page.

No interaction 2,459 drugs checked — show the list

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

Showing the 60 most looked-up of 2,459 medications checked with no known interaction — see the full Testolone list.

See the full Testolone interactions page
See every supplement checked against Diltiazem, ranked by severity
Evidence & sources

Testolone References

The 7 references that drive our Testolone monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Joseph JF, Parr MK. Synthetic androgens as designer supplements. Curr Neuropharmacol. 2015;13(1):89-100. PubMed
  2. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
  3. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
  4. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017
  5. LoRusso P, Hamilton E, Ma C, et al. A first-in-human phase 1 study of a novel selective androgen receptor modulator (SARM), RAD140, in ER+/HER2- metastatic breast cancer. Clin Breast Cancer 2022;22(1):67-77. PubMed
  6. Barbara M, Dhingra S, Mindikoglu AL. Drug-induced liver injury associated with alpha bolic (RAD-140) and alpha elite (RAD-140 and LGD-4033). ACG Case Rep J 2020;7(6):e00409. PubMed
  7. Padappayil RP, Chandini Arjun A, Vivar Acosta J, Ghali W, Mughal MS. Acute myocarditis from the use of selective androgen receptor modulator (SARM) RAD-140 (Testolone). Cureus. 2022;14(1):e21663. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Testolone and Diltiazem Together: Common Questions

Is it safe to take Testolone with Diltiazem?
We do not list a known interaction between Testolone and Diltiazem. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Testolone and Diltiazem have any of the same side effects?
Yes — our sources link each of them separately to 7 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Testolone and Diltiazem combination checked?
Interactions in our licensed database are recorded against drug classes. Diltiazem is filed under 9 classifications, and Testolone has documented interactions with 1 drug class — none of Diltiazem's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Testolone interact with any other medications?
Yes. Testolone has 370 documented drug interactions in our database — Diltiazem is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Diltiazem interact with any supplements?
Yes. Diltiazem has documented interactions with 260 supplements in our database — Testolone is not one of them. The Diltiazem interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Testolone monograph Uses, safety profile, and every drug interaction in one place Diltiazem drug information The full plain-English guide to this medication Diltiazem supplement interactions Every supplement checked against Diltiazem, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Diltiazem and Testolone?

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.