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Dietary supplement

Astaxanthin 4 mg Ingredients & Drug Interactions

by NOW

Astaxanthin 4 mg label
See full label image
Softgel Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Oct 7, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Astaxanthin 4 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Astaxanthin 4 mg is a dietary supplement by NOW with 1 active ingredient. Its ingredients are commonly taken for antioxidant support, skin health and aging, eye health.Based on those ingredients, 673 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Zanthin. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Astaxanthin 4 mg by NOW

Ask about any prescription or over-the-counter medication and we check it for interactions with Astaxanthin 4 mg by NOW — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Astaxanthin 4 mg by NOW

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: astaxanthin (Zanthin brand), a natural carotenoid pigment. The remaining ingredients are inactive excipients—corn starch, glycerin, carrageenan, water, extra virgin olive oil, mixed tocopherols, and rosemary leaf extract—which serve as softgel capsule material and preservatives.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Astaxanthin's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: Eye health and free radical scavenging support.
  • We looked for evidence on: Age-related macular degeneration (AMD), Dry eye, Ocular antioxidant protection, Retinal health.
  • The closest evidence on file: Astaxanthin is rated "Insufficient Reliable Evidence To Rate" for Age-related macular degeneration (AMD) (Natural Medicines).
  • Also on file: Astaxanthin is rated "Insufficient Reliable Evidence To Rate" for Dry eye.

The evidence we hold on astaxanthin doesn't establish its effectiveness for any condition. Astaxanthin has been studied for age-related cognitive decline, age-related macular degeneration (AMD), aging skin, Alzheimer disease, athletic performance, and carpal tunnel syndrome, but in each case the data are rated insufficient to say whether it works.

If effectiveness for a specific use matters to you, talk with your pharmacist about what the broader research shows.

The evidence, ingredient by ingredient Astaxanthin

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Astaxanthin is generally well tolerated in studies, though long-term safety data are limited. The most common side effects are abdominal pain, diarrhea, and red-colored stools.

A small number of trial participants taking higher doses (40 mg daily) reported severe stomach pain, and a few taking 6 mg daily experienced increased bowel movements or red stools. The safety data available advise against use during pregnancy and while breastfeeding; talk with your doctor or pharmacist if either applies to you.

Side effects, ingredient by ingredient Astaxanthin

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Astaxanthin.
  • The most serious interaction on file is rated Moderate.
  • For scale: 674 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check these medication types before starting astaxanthin: drugs metabolized by CYP3A4 (Moderate) and CYP2B6 (Moderate). These are broad categories covering many medications—statins, some blood pressure drugs, antihistamines, and others.

Your pharmacist can tell you whether any of yours are affected.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

Astaxanthin may be worth considering if you're interested in general antioxidant support, but the evidence for any specific health benefit isn't established in the data we hold. Before you start, check your medications with your pharmacist—the ingredient interacts theoretically with a large number of drugs through liver metabolism.

Pregnancy and breastfeeding: talk with your doctor first.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Mar 22, 2024.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Astaxanthin 4 mg, straight from the product label.

Brand NOW
Barcode (UPC) 733739032515
Net contents 60 Veggie Softgel(s)
Market status On market
Date entered into DSLD Mar 22, 2024
DSLD ID 307920
Product type Non-nutrient/non-botanical
Supplement form Softgel Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Kosher, Halal, Gluten Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Astaxanthin 4 mg by NOW, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Veggie Softgel(s)
Maximum serving Sizes:
1 Veggie Softgel(s)
Servings per container
60
UPC/BARCODE
733739032515
IngredientAmount% DV
Zanthin4 mg--

Other ingredients: Corn Starch, Modified, Glycerin, Carrageenan, Water, Extra Virgin Olive Oil, Mixed Tocopherols, Rosemary Leaf Extract

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested usage: Take 1 softgel 1 to 2 times daily with food.

Formula

Astaxanthin is a naturally occurring carotenoid with a unique structure that is known to be a potent free radical scavenger. Because astaxanthin freely crosses the blood-brain and blood-retina barriers, it can neutralize free radicals in the eye and central nervous system. Scientific studies also demonstrate that astaxanthin can support the body's healthy and balanced immune system responses. This NOW product features Zanthin, which can help to support overall ocular health and promote a healthy nervous system.

Triangle K (Kosher)

Crescent H (Halal)

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only. Keep out of reach of children.

Consult physician if pregnant/nursing, taking medication, or have a medical condition.

Mixed tocopherols from non-GMO soy.

Not manufactured with wheat, gluten, milk, egg, fish, shellfish or sesame ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Formulation

Natural color variation may occur in this product

Supports eye health Potent free radical scavenger Healthy immune system response

Non-GMO

Vegetarian/Vegan

Made and quality tested in the USA with globally sourced ingredients.

Not manufactured with wheat, gluten, milk, egg, fish, shellfish or sesame ingredients.

General Statements

This bottle is made from 100% PCR (post-consumer recycled) resin.

General health Family owned since 1968.

FDA Statement of Identity

A Dietary Supplement

Seals/Symbols

Triangle K (Kosher)

Crescent H (Halal) GMP Quality Assured

Brand IP Statement(s)

Zanthin is a registered trademark of Valensa International.

Storage

Store in a cool, dry place after opening.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Astaxanthin 4 mg by NOW label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Astaxanthin 4 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Astaxanthin 4 mg by NOW

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Veggie Softgel(s) Dosage formSoftgel Capsule Servings per container60 Amounts shown are per serving.

Zanthin

Interacts with
673 drugs
4 mg per serving Form: Astaxanthin

Astaxanthin is a reddish carotenoid pigment with strong antioxidant activity in the lab, and it is widely promoted for skin, eye, heart, and exercise...

Zanthin monograph & interactions

Other (inactive) ingredients: Corn Starch, Modified, Glycerin, Carrageenan, Water, Extra Virgin Olive Oil, Mixed Tocopherols, Rosemary Leaf Extract. These complete the product’s ingredient list but are not active constituents.

Interaction report

Astaxanthin 4 mg by NOW Drug Interactions

Want to check YOUR meds against Astaxanthin 4 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
673Drugs
673 Moderate

Ingredients driving the most interactions

Zanthin 673

Individual Drug Interactions

The ingredients in Astaxanthin 4 mg interact with 673 drugs. Click any drug to see the details.

1 of the 1 ingredient in Astaxanthin 4 mg interact with drugs. Each result below shows which ingredient is responsible. Zanthin

Each ingredient & the kinds of drugs it affects

For each ingredient in Astaxanthin 4 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Zanthin2 drug types · 673 drugs

Cytochrome P450 2B6 (Cyp2B6) Substrates

Theoretically, astaxanthin may decrease levels of drugs metabolized by CYP2B6.
In vitro research shows that astaxanthin induces cytochrome CYP2B6 enzyme activity in human hepatocytes. This effect has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, astaxanthin may decrease levels of drugs metabolized by CYP3A4.
In vitro research shows that astaxanthin induces CYP3A4 enzyme activity in human hepatocytes. This effect has not been reported in humans.

Likelihood Possible Evidence D
Zanthin full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Astaxanthin 4 mg, from the product label.

NOW

See all NOW products
Name
NOW Foods
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

Astaxanthin 4 mg by NOW: Common Questions

Does Astaxanthin 4 mg by NOW interact with any medications?
Yes. Based on its ingredients, Astaxanthin 4 mg has a known interaction with 673 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Astaxanthin 4 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
What's astaxanthin, and where does it come from?
Astaxanthin is a natural carotenoid pigment—the same compound that gives salmon and shrimp their pink color. In this product, the ingredient goes by the brand name Zanthin.
Will astaxanthin help with my age-related macular degeneration or cognitive decline?
The evidence we hold doesn't establish whether astaxanthin works for those conditions. Both have been studied, but the data aren't yet reliable enough to say. Talk with your doctor about what the broader research shows.
What side effects should I watch for?
Most people tolerate it well. The most common side effects are abdominal pain, diarrhea, and red-colored stools. If you notice severe stomach pain or frequent bowel changes, stop and tell your pharmacist.
Is astaxanthin safe if I'm pregnant or breastfeeding?
There isn't enough safety data to know either way. The available evidence advises against it during pregnancy and while breastfeeding. Talk with your doctor or pharmacist for personalized advice if you're in either situation.
Why does the product say it might affect 661 medications?
Astaxanthin may slow down two liver enzymes (CYP3A4 and CYP2B6) that break down many common drugs—statins, blood pressure medications, antihistamines, and others. That's why the number is large. Your exact medications may or may not be affected; check with your pharmacist.
Has this astaxanthin effect on my medications actually been proven in people?
No—it's only been shown in test-tube studies of human liver cells so far. It hasn't yet been reported in actual patients. That's why the interactions are rated Moderate rather than Major, and why it's important to check your specific medications.

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

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Astaxanthin 4 mg label
Go deeper

The Full Monographs Behind Astaxanthin 4 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Astaxanthin

Interacts with 673 drugs

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 promis...

Read the full Astaxanthin monograph →
Sources

Sources & How We Checked

Astaxanthin 4 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 3 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Astaxanthin 3 references
  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

See these in context on the Astaxanthin monograph →

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

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