Drug & supplement interaction

Astaxanthin + Phendimetrazine

Phendimetrazine brand names: Plegine, Metra, Weightrol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Astaxanthin and Phendimetrazine 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.

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Interaction report

Astaxanthin and Phendimetrazine

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 Phendimetrazine and Astaxanthin 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.

Astaxanthin safety at a glance

Astaxanthin overall Use caution Generally well tolerated in studies, but long-term safety data are limited.
Pregnancy Avoid Not enough safety data, so it is best to avoid during pregnancy.
Breastfeeding Avoid Not enough safety data, so it is best to avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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

Why No Interaction Is Listed for Phendimetrazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phendimetrazine is filed under a single classification — oral drugs. Astaxanthin has documented interactions with 2 drug classes — the most serious being cytochrome p450 2b6 (cyp2b6) substrates (moderate) and cytochrome p450 3a4 (cyp3a4) substrates (moderate) — and none of Phendimetrazine’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

Astaxanthin Does Interact With Other Medications

Astaxanthin has 671 moderate known drug interactions in our database — Phendimetrazine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 671 No known interaction 2,159 (incl. Phendimetrazine)
Taking anything else?

Check Another of Your Medications Against Astaxanthin

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

What to actually watch for

No Interaction Found — But Data Suggests Astaxanthin and Phendimetrazine 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.

  • Stomach pain / Diarrhea Additional detail

    Astaxanthin

    “Orally, astaxanthin 6 mg daily has caused two cases of increased bowel movements and two cases of red fecal color. A higher dose of astaxanthin (AstaCarox, AstaReal AB) 40 mg daily has caused severe stomach/abdominal pain in two patients.”

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

    2 sources cited
    1. 91736. Choi HD, Youn YK, Shin WG. Positive effects of astaxanthin on lipid profiles and oxidative stress in overweight subjects. Plant Foods Hum Nutr. 2011;66:363-369. PubMed
    2. 19165. Kupcinskas L, Lafolie P, Lignell A, et al. Efficacy of the natural antioxidant astaxanthin in the treatment of functional dyspepsia in patients with or without Helicobacter pylori infection: A prospective, randomized, double blind, and placebo-controlled

    Phendimetrazine

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

Effects for Phendimetrazine come from the ADVERSE REACTIONS section of its FDA label; effects for Astaxanthin come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Phendimetrazine Is Prescribed For, and What Astaxanthin Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Phendimetrazine is a prescription medicine with approved uses on its FDA label. Astaxanthin is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Phendimetrazine is prescribed for: Phendimetrazine tartrate is used to help manage exogenous obesity (excess body weight from outside causes like diet and lifestyle) as a short-term addition to a calorie-restricted diet. It is intended for adults with a BMI of 30 or higher, or a BMI of 27 or higher when other risk factors — such as high blood pressure, diabetes, or high cholesterol — are also present. It is approved for use as monotherapy only, meaning it must not be combined with other weight-loss drugs or stimulants. Both the tablet form and the extended-release capsule form are approved for this purpose.

Read the rest of what Phendimetrazine is prescribed for

This medication is meant to be used for only a few weeks as part of a broader weight-management plan.

Astaxanthin has been studied for:

  • Obesity studied, not established Astaxanthin has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Astaxanthin for obesity

    Although there is interest in using oral astaxanthin for weight loss, there is insufficient reliable information about the clinical effects of astaxanthin for this purpose.

  • Diabetes studied, not established Astaxanthin has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Astaxanthin for diabetes

    It is unclear if oral astaxanthin is beneficial for diabetes.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Phendimetrazine on your own; if you are taking Astaxanthin for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Astaxanthin or Phendimetrazine

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

This page covers Astaxanthin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phendimetrazine page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Phendimetrazine page

“Of the 17 supplements on file for phendimetrazine, an appetite-suppressant stimulant prescribed short term for weight loss, activated charcoal is the one that demands real caution. Charcoal binds medications in the gut and can sharply cut how much of a drug your body absorbs, leaving you with less appetite control than your prescriptio…”

Reviewed by 2 · Jul 18, 2026

Open the Phendimetrazine interaction page

One more smart check

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

We hold 2,223 real supplement products containing Astaxanthin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Astaxanthin. Even though Astaxanthin itself has no known interaction with Phendimetrazine, 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 Astaxanthin and Phendimetrazine 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 Astaxanthin
Top 10%

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

29 days ago today
Medication Phendimetrazine
Top 25%

#376 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 Astaxanthin reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Astaxanthin and Phendimetrazine 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 Astaxanthin

What is Astaxanthin?

Astaxanthin
  • Antioxidant support
  • Skin health and aging
  • Eye health
  • Exercise recovery
  • Heart and inflammation support

Astaxanthin is a reddish carotenoid pigment with strong antioxidant activity in the lab, and it is widely promoted for skin, eye, heart, and exercise benefits. Early human studies are promising for a few uses, but the overall evidence is still limited and not strong enough to make firm claims. It appears generally well tolerated at typical supplement doses, but talk with your pharmacist or doctor before starting it.

Pigment extracted from microalgae (mainly Haematococcus pluvialis), yeast, and some seafood · Capsules, soft gels, tablets, and as an ingredient in some skin creams

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

Astaxanthin: dosing

There is no official standardized dose for astaxanthin, and amounts used in studies have varied. Because of this, the best approach is to follow the directions on the product label.Astaxanthin is fat-soluble, so it is often taken with a meal that contains some fat to help absorption.

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

Read the full Astaxanthin monograph & all interactions
Medication

About Phendimetrazine

What Is Phendimetrazine Used For?

Brand names: Plegine, Metra, Weightrol

Phendimetrazine tartrate is used to help manage exogenous obesity (excess body weight from outside causes like diet and lifestyle) as a short-term addition to a calorie-restricted diet. It is intended for adults with a BMI of 30 or higher, or a BMI of 27 or higher when other risk factors — such as high blood pressure, diabetes, or high cholesterol — are also present.

It is approved for use as monotherapy only, meaning it must not be combined with other weight-loss drugs or stimulants. Both the tablet form and the extended-release capsule form are approved for this purpose. This medication is meant to be used for only a few weeks as part of a broader weight-management plan.

See full Phendimetrazine drug information
Keep checking

Other Drugs & Astaxanthin

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

0Major
671Moderate
0Minor
2,158No known interaction
671 Moderate 2,158 No interaction
Moderate

671 interactions

Showing 60 of 671 moderate interactions — see all 671 on the Astaxanthin page.

No interaction 2,158 drugs checked — show the list

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

Showing the 60 most looked-up of 2,158 medications checked with no known interaction — see the full Astaxanthin list.

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

Astaxanthin References

The 3 references that drive our Astaxanthin 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. Kupcinskas L, Lafolie P, Lignell A, et al. Efficacy of the natural antioxidant astaxanthin in the treatment of functional dyspepsia in patients with or without Helicobacter pylori infection: A prospective, randomized, double blind, and placebo-controlled
  2. Kistler, A., Liechti, H., Pichard, L., Wolz, E., Oesterhelt, G., Hayes, A., and Maurel, P. Metabolism and CYP-inducer properties of astaxanthin in man and primary human hepatocytes. Arch.Toxicol. 2002;75(11-12):665-675. PubMed
  3. Choi HD, Youn YK, Shin WG. Positive effects of astaxanthin on lipid profiles and oxidative stress in overweight subjects. Plant Foods Hum Nutr. 2011;66:363-369. 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 Astaxanthin and Phendimetrazine Together: Common Questions

Is it safe to take Astaxanthin with Phendimetrazine?
We do not list a known interaction between Astaxanthin and Phendimetrazine. 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 Astaxanthin and Phendimetrazine have any of the same side effects?
Yes — our sources link each of them separately to 2 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.
Are Astaxanthin and Phendimetrazine used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Astaxanthin in each. That is a conversation for your prescriber, especially if Phendimetrazine is being adjusted to a target.
How was the Astaxanthin and Phendimetrazine combination checked?
Interactions in our licensed database are recorded against drug classes. Phendimetrazine is filed under 1 classification, and Astaxanthin has documented interactions with 2 drug classes — none of Phendimetrazine'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 Astaxanthin interact with any other medications?
Yes. Astaxanthin has 671 documented drug interactions in our database — Phendimetrazine 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 Phendimetrazine interact with any supplements?
Yes. Phendimetrazine has documented interactions with 17 supplements in our database — Astaxanthin is not one of them. The Phendimetrazine 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

Astaxanthin monograph Uses, safety profile, and every drug interaction in one place Phendimetrazine drug information The full plain-English guide to this medication Phendimetrazine supplement interactions Every supplement checked against Phendimetrazine, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phendimetrazine and Astaxanthin?

Our pharmacists answer your medication & supplement questions — free.

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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.