Drug & supplement interaction

Astaxanthin + Carbidopa

Carbidopa brand name: Lodosyn.

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 Astaxanthin and Carbidopa 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 Carbidopa

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 Carbidopa 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 Carbidopa and Astaxanthin? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Carbidopa

Interactions in our licensed database are recorded against drug classes, not just single drug names. Carbidopa is filed under 3 classifications — including 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 Carbidopa’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 — Carbidopa 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. Carbidopa)
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 Carbidopa 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

    Carbidopa

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

Effects for Carbidopa come from the ADVERSE REACTIONS section of its FDA label; effects for Astaxanthin come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 52,609 voluntary FDA FAERS reports for Carbidopa 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.

From our Q&A

Questions About Astaxanthin or Carbidopa

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 Carbidopa, 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 Carbidopa

This page covers Astaxanthin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Carbidopa page lists 21 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Magnesium (major), 5-htp (moderate), Coffee Charcoal (moderate) and European Mandrake (moderate).

By severity: 2 major · 10 moderate · 9 minor.

From our pharmacist’s overview on the Carbidopa page

“Carbidopa (Lodosyn) keeps levodopa working in Parkinson's disease, so anything that blocks its absorption can cost real motor control, and two of the 21 supplements on this list do exactly that at a level rated major. Magnesium is the one that surprises people: in a human study it cut carbidopa absorption by 81 percent and levodopa's b…”

Reviewed by 2 · Jul 18, 2026

Open the Carbidopa 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 Carbidopa, 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 Carbidopa 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%

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

29 days ago today
Medication Carbidopa
Top half

#1,203 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 20, 2026. The Astaxanthin and Carbidopa 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 Carbidopa

What Is Carbidopa Used For?

Brand name: Lodosyn

Carbidopa tablets — sold under the brand name Lodosyn and as generic carbidopa — are used together with levodopa or carbidopa-levodopa to manage symptoms of Parkinson's disease, postencephalitic parkinsonism, and symptomatic parkinsonism that can result from carbon monoxide or manganese poisoning. Carbidopa is never used alone; it always works as a partner to levodopa-based therapy.

Lodosyn is specifically used when a patient taking carbidopa-levodopa isn't getting enough daily carbidopa from that combination, or when a patient needs the two drugs individually titrated (adjusted) rather than taken as a fixed combination. Adding carbidopa helps reduce the nausea and vomiting that levodopa often causes and allows lower doses of levodopa to be used.

Most-Reported Side Effects for Carbidopa

From FAERS, the FDA’s public side-effect reporting system (52,609 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fall 4,954 reports
Hallucination 4,554 reports
Tremor 3,533 reports
Dyskinesia 3,174 reports
Dizziness 2,837 reports
See full Carbidopa 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 Carbidopa, 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 Carbidopa Together: Common Questions

Is it safe to take Astaxanthin with Carbidopa?
We do not list a known interaction between Astaxanthin and Carbidopa. 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 Carbidopa 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.
How was the Astaxanthin and Carbidopa combination checked?
Interactions in our licensed database are recorded against drug classes. Carbidopa is filed under 3 classifications, and Astaxanthin has documented interactions with 2 drug classes — none of Carbidopa'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 — Carbidopa 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 Carbidopa interact with any supplements?
Yes. Carbidopa has documented interactions with 21 supplements in our database — Astaxanthin is not one of them. The Carbidopa 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 Carbidopa drug information The full plain-English guide to this medication Carbidopa supplement interactions Every supplement checked against Carbidopa, 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 Carbidopa and Astaxanthin?

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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.