Drug & supplement interaction

1,3-dmba + Timolol

Timolol brand names: Blocadren, Timol, Timoptic.

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

1,3-dmba has a minor interaction with Timolol. Theoretically, 1,3-DMBA might modestly increase the levels of CYP2D6 substrates.

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

1,3-dmba and Timolol

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

Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Timolol

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

Theoretically, 1,3-DMBA might modestly increase the levels of CYP2D6 substrates.
In vitro research shows that 1,3-DMBA weakly inhibits CYP2D6 enzymes.
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 gist for timolol. Your liver uses an enzyme called CYP2D6 to help clear oral timolol from your body. Lab studies suggest 1,3-DMBA may weakly block that enzyme, so in theory a bit more timolol could hang around. That could mean a slightly stronger effect, like a lower heart rate, more dizziness, or feeling extra tired.

But honestly, this is the smaller worry here. The bigger concern is that 1,3-DMBA is a banned, unsafe stimulant that raises heart rate and blood pressure, working directly against what timolol is doing for you. The enzyme part is theoretical (only lab data so far). I'd steer clear of 1,3-DMBA entirely and chat with your pharmacist or doctor before using any product containing it.

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-dmba Also Interacts With Other Medications

1,3-dmba has 172 moderate, 148 minor known drug interactions in our database — the Timolol one above is one of them. If you take anything else, check it against the full list below.

Moderate 172 Minor 148 No known interaction 2,510 (incl. Timolol)
Taking anything else?

Check Another of Your Medications Against 1,3-dmba

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

From our Q&A

Questions About 1,3-dmba or Timolol

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-dmba or Timolol, 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 Timolol

This page covers 1,3-dmba only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Timolol page lists 183 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), Indian Snakeroot (major) and Tyramine (major).

By severity: 5 major · 151 moderate · 27 minor.

From our pharmacist’s overview on the Timolol page

“The supplement list for timolol (Blocadren, Timoptic) calls for genuine care, starting with its five major-rated entries. Timolol is a beta-blocker that slows the heart and lowers blood pressure, and even the eye-drop form absorbs enough to matter.”

Reviewed by 2 · Jul 18, 2026

Open the Timolol interaction page

How much people look this up

Where 1,3-dmba and Timolol 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-dmba
Steady interest

#1,035 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Timolol
Steady interest

#1,639 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-dmba

What is 1,3-dmba?

  • Athletic and workout performance
  • Energy and stimulation
  • Weight loss and fat burning
  • Appetite suppression
  • Focus and concentration

1,3-DMBA is a synthetic stimulant chemically similar to the banned stimulant DMAA, and it is not a proven or safe dietary ingredient. The U.S. FDA considers supplements containing it adulterated, and it is banned in sports. Because of serious heart and stroke risks, it is best to avoid products that contain it.

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

About Timolol

What Is Timolol Used For?

Brand names: Blocadren, Timol, Timoptic

Timolol is available in ophthalmic (eye) forms and as an oral tablet, and each form has its own approved uses. Ophthalmic formulations — including Betimol, Istalol, Timolol GFS, Timolol hemihydrate, Timolol Maleate eye drops, and Timolol Maleate Ophthalmic Gel Forming Solution — are used to lower elevated intraocular pressure (pressure inside the eye) in people with ocular hypertension or open-angle glaucoma.

Timolol Maleate tablets are used orally for three separate conditions: treating high blood pressure (alone or combined with other blood pressure medicines), reducing the risk of death and repeat heart attack in people who have survived a heart attack and are clinically stable, and preventing migraine headaches.

See full Timolol drug information
Keep checking

Other Drugs & 1,3-dmba

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

0Major
172Moderate
148Minor
2,509No known interaction
172 Moderate 148 Minor 2,509 No interaction
Moderate

172 interactions

Showing 60 of 172 moderate interactions — see all 172 on the 1,3-dmba page.

Minor

148 interactions

Showing 60 of 148 minor interactions — see all 148 on the 1,3-dmba page.

No interaction 2,509 drugs checked — show the list

We also checked 1,3-dmba 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-dmba list.

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

Can you take 1,3-dmba with Timolol?
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 1,3-dmba and Timolol 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 Timolol and 1,3-dmba?

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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.