Drug & supplement interaction

1,3-dmaa + Tamoxifen Citrate

Tamoxifen Citrate brand names: Nolvadex, Soltamox.

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

1,3-dmaa has a moderate interaction with Tamoxifen Citrate. 1,3-DMAA strongly inhibits cytochrome P450 2D6 (CYP2D6) enzymes in vitro.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

1,3-dmaa and Tamoxifen Citrate

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Tamoxifen Citrate

Tamoxifen Citrate falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group 1,3-dmaa interacts with.

1,3-DMAA strongly inhibits cytochrome P450 2D6 (CYP2D6) enzymes in vitro. Theoretically, 1,3-DMAA can increase levels of CYP2D6 substrates. Some of drugs that are CYP2D6 substrates include amitriptyline (Elavil), clozapine (Clozaril), codeine, desipramine (Norpramin), donepezil (Aricept), fentanyl (Duragesic), flecainide (Tambocor), fluoxetine (Prozac), meperidine (Demerol), methadone (Dolophine), metoprolol (Lopressor, Toprol XL), olanzapine (Zyprexa), ondansetron (Zofran), tramadol (Ultram), trazodone (Desyrel), and others.
Severity Moderate 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 an important wrinkle with tamoxifen: it's really a prodrug. Your body has to convert it into its active form, called endoxifen, and the enzyme CYP2D6 does most of that work. That's the same enzyme lab studies suggest 1,3-DMAA can block. So unlike most interactions where a blocker makes a drug build up, here blocking CYP2D6 could mean less active endoxifen, which may weaken the cancer protection tamoxifen is meant to give you.

I want to be honest about the evidence though: this is based only on test-tube data, not real people, so it's theoretical. But since DMAA itself is banned and unsafe (heart and blood pressure risks), the simplest answer is to avoid it. Please talk with your oncologist or pharmacist before combining anything with tamoxifen.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu Y, Santillo MF. Cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants in dietary supplements. Drug Test Anal. 2016;8(3-4):307-10. 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

1,3-dmaa Also Interacts With Other Medications

1,3-dmaa has 320 moderate known drug interactions in our database — the Tamoxifen Citrate one above is one of them. If you take anything else, check it against the full list below.

Moderate 320 No known interaction 2,510 (incl. Tamoxifen Citrate)
Taking anything else?

Check Another of Your Medications Against 1,3-dmaa

Covers the 2,830 medications we’ve checked against 1,3-dmaa. Pick one to open its full report.

From our Q&A

Questions About 1,3-dmaa or Tamoxifen Citrate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers 1,3-dmaa or Tamoxifen Citrate, 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 Tamoxifen Citrate

This page covers 1,3-dmaa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tamoxifen Citrate page lists 210 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 166 moderate · 33 minor.

From our pharmacist’s overview on the Tamoxifen Citrate page

“Tamoxifen (Nolvadex, Soltamox) often stands between a breast cancer patient and a recurrence, so the stakes on this page run higher than usual. Eleven of the 210 supplements and herbs on file carry a major rating, and those eleven deserve your attention ahead of everything else.”

Reviewed by 2 · Jul 18, 2026

Open the Tamoxifen Citrate interaction page

One more smart check

Taking 1,3-dmaa as Part of a Dietary Supplement Product? Check It for Interactions

We hold 94 real supplement products containing 1,3-dmaa, each one broken down to its full ingredient list — and combination products often carry several ingredients besides 1,3-dmaa. Your product may carry other ingredients that interact with Tamoxifen Citrate too, on top of 1,3-dmaa — 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 1,3-dmaa and Tamoxifen Citrate 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 1,3-dmaa
Top half

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

29 days ago today
Medication Tamoxifen Citrate
Top 25%

#335 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 1,3-dmaa

What is 1,3-dmaa?

1,3-dmaa
  • Energy and stimulation
  • Pre-workout performance
  • Weight loss
  • Appetite suppression
  • Focus and concentration

DMAA (1,3-dimethylamylamine) is a synthetic stimulant that was sold in pre-workout and weight-loss supplements but has been linked to serious harm, including high blood pressure, heart problems, strokes, and deaths. The U.S. FDA and regulators in many countries have declared it illegal and unsafe in dietary supplements, so it should be avoided.

Read the full 1,3-dmaa monograph & all interactions
Medication

About Tamoxifen

What Is Tamoxifen Used For?

Brand names: Nolvadex, Soltamox

Tamoxifen is used to treat estrogen receptor-positive metastatic breast cancer in both women and men, and as follow-up (adjuvant) therapy after surgery for early-stage breast cancer in women. It also reduces the occurrence of cancer in the opposite breast when used as adjuvant therapy.

In women with ductal carcinoma in situ (DCIS — an early, non-invasive breast change) following surgery and radiation, tamoxifen lowers the risk of developing invasive breast cancer. It is also approved to reduce the risk of breast cancer in women who are at high risk but have not yet been diagnosed. Both Tamoxifen Citrate tablets and Soltamox oral solution share these indications.

See full Tamoxifen drug information
Keep checking

Other Drugs & 1,3-dmaa

Browse every other medication we’ve checked against 1,3-dmaa — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
320Moderate
0Minor
2,509No known interaction
320 Moderate 2,509 No interaction
Moderate

320 interactions

Showing 60 of 320 moderate interactions — see all 320 on the 1,3-dmaa page.

No interaction 2,509 drugs checked — show the list

We also checked 1,3-dmaa against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,509 medications checked with no known interaction — see the full 1,3-dmaa list.

See the full 1,3-dmaa interactions page
See every supplement checked against Tamoxifen Citrate, 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
1,3-dmaa monograph › Uses, safety, and every drug interaction in one place Tamoxifen Citrate supplement interactions › Every supplement checked against Tamoxifen Citrate, ranked by severity Tamoxifen 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 1,3-dmaa and Tamoxifen Citrate Together: Common Questions

Can you take 1,3-dmaa with Tamoxifen Citrate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the 1,3-dmaa and Tamoxifen Citrate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Tamoxifen Citrate and 1,3-dmaa?

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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.