Drug & supplement interaction

Dimethylhexylamine (dmha) + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

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

Dimethylhexylamine (dmha) has a moderate interaction with Phentermine. Theoretically, combining DMHA with stimulant drugs might increase the risk of adverse cardiovascular effects.

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

Dimethylhexylamine (dmha) and Phentermine

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

Moderate

STIMULANT DRUGS

Why this applies to Phentermine

Phentermine falls under STIMULANT DRUGS — the group Dimethylhexylamine (dmha) interacts with.

Theoretically, combining DMHA with stimulant drugs might increase the risk of adverse cardiovascular effects.
DMHA is thought to have stimulant effects.
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 the simple version: both phentermine and DMHA are stimulants, so stacking them is like pressing the gas pedal twice. Phentermine already nudges up your heart rate and blood pressure and can leave you feeling jittery, restless, or unable to sleep. Adding DMHA on top can pile those effects together, which may raise the chance of a racing or pounding heart, spikes in blood pressure, chest discomfort, anxiety, or trouble sleeping.

To be fair, this concern is theoretical, based on how these two work rather than hard studies in people. But DMHA itself has been flagged by the FDA as an unapproved and risky ingredient, so I'd steer clear of it altogether. Please loop in your pharmacist or doctor before mixing anything with your phentermine.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rasmussen N, Keizers PH. History full circle: 'novel' sympathomimetics in supplements. Drug Test Anal 2016;8(3-4):283-6. PubMed
  2. Monroe RR, Drell HJ. Oral use of stimulants obtained from inhalers. J Am Med Assoc 1947; 135(14):909-15. PubMed
  3. Fellows EJ. The pharmacology of 2-amino-6-methylheptane. J Pharmacol Exp Ther 1947;90(4):351-8. DOI

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

Dimethylhexylamine (dmha) Also Interacts With Other Medications

Dimethylhexylamine (dmha) has 171 moderate known drug interactions in our database — the Phentermine one above is one of them. If you take anything else, check it against the full list below.

Moderate 171 No known interaction 2,659 (incl. Phentermine)
Taking anything else?

Check Another of Your Medications Against Dimethylhexylamine (dmha)

Covers the 2,830 medications we’ve checked against Dimethylhexylamine (dmha). Pick one to open its full report.

From our Q&A

Questions About Dimethylhexylamine (dmha) or Phentermine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Dimethylhexylamine (dmha) or Phentermine, 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 Phentermine

This page covers Dimethylhexylamine (dmha) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

One more smart check

Taking Dimethylhexylamine (dmha) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 72 real supplement products containing Dimethylhexylamine (dmha), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Dimethylhexylamine (dmha). Your product may carry other ingredients that interact with Phentermine too, on top of Dimethylhexylamine (dmha) — 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 Dimethylhexylamine (dmha) and Phentermine 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 Dimethylhexylamine (dmha)
Steady interest

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

29 days ago today
Medication Phentermine
Top 25%

#412 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 Dimethylhexylamine (dmha)

What is Dimethylhexylamine (dmha)?

  • Pre-workout energy
  • Fat loss and weight management
  • Athletic performance
  • Appetite suppression
  • Focus and stimulation

DMHA (dimethylhexylamine, also called octodrine) is a synthetic stimulant added to some pre-workout and weight-loss supplements, often falsely labeled as a natural plant extract. It has not been shown to be safe as a dietary supplement, has been flagged by the FDA as an unapproved and potentially dangerous ingredient, and is best avoided. Talk to a pharmacist or doctor before using any product that contains it.

Read the full Dimethylhexylamine (dmha) monograph & all interactions
Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information
Keep checking

Other Drugs & Dimethylhexylamine (dmha)

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

0Major
171Moderate
0Minor
2,658No known interaction
171 Moderate 2,658 No interaction
Moderate

171 interactions

Showing 60 of 171 moderate interactions — see all 171 on the Dimethylhexylamine (dmha) page.

No interaction 2,658 drugs checked — show the list

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

Showing the 60 most looked-up of 2,658 medications checked with no known interaction — see the full Dimethylhexylamine (dmha) list.

See the full Dimethylhexylamine (dmha) interactions page
See every supplement checked against Phentermine, 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
Dimethylhexylamine (dmha) monograph › Uses, safety, and every drug interaction in one place Phentermine supplement interactions › Every supplement checked against Phentermine, ranked by severity Phentermine 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 Dimethylhexylamine (dmha) and Phentermine Together: Common Questions

Can you take Dimethylhexylamine (dmha) with Phentermine?
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 Dimethylhexylamine (dmha) and Phentermine 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 Phentermine and Dimethylhexylamine (dmha)?

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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.