Drug & supplement interaction

Duckweed + Sevelamer

Sevelamer brand name: Renagel.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Duckweed and Sevelamer 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 label for Sevelamer states a food rule worth keeping to.

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Interaction report

Duckweed and Sevelamer

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 Sevelamer and Duckweed 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Duckweed at all — not against Sevelamer, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Duckweed safety at a glance

Duckweed overall Use caution Generally considered a food in some cultures, but supplement quality and water contamination are real concerns.
Pregnancy Avoid There is not enough reliable safety information, so avoidance is the safer choice.
Breastfeeding Avoid Safety during breastfeeding has not been established, so avoid it.

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

Still wondering about combining Sevelamer and Duckweed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Sevelamer’s Own FDA Label Lists

This is not an interaction — none of it involves Duckweed. These are the most notable effects listed in the ADVERSE REACTIONS section of Sevelamer’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 3 of them are worth acting on rather than waiting out — marked below.

  • A bowel blockage Worth acting on
  • Bleeding or bruising Worth acting on
  • An allergic reaction Worth acting on
  • Bloating or gas
  • Stomach upset
  • Constipation
  • Itching
  • Stomach pain
  • Diarrhea
  • A skin rash

Showing the 10 most notable of 12 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Sevelamer. Read the label on DailyMed › Duckweed’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Duckweed side to compare — that is a limit of the record, not a statement that Duckweed has no side effects.

How to take them

Some Sevelamer Products Have a Food Rule — Duckweed Should Not Break It

At least one FDA label for a product containing Sevelamer says to take it with food. If you take Duckweed on an empty stomach out of habit, keep them separate — and take Sevelamer with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Sevelamer products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

2 DOSAGE AND ADMINISTRATION Starting dose of Renvela is 0.8 or 1.6 grams administered orally three times per day with meals based on serum phosphorus levels for adult patients and based on body surface area (BSA) category for pediatric patients.

From the Dosage and Administration section of the FDA label we read for Sevelamer — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Sevelamer

This page covers Duckweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sevelamer page lists 18 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 · 10 minor.

From our pharmacist’s overview on the Sevelamer page

“Kidney patients who take sevelamer (Renagel) to control phosphorus have a real reason to pause over this page, and activated charcoal is why. It carries the only major rating here because it can trap medicines in the gut and sharply cut the amount the body actually gets.”

Reviewed by 2 · Jul 18, 2026

Open the Sevelamer interaction page

One more smart check

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

We hold 6 real supplement products containing Duckweed, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Duckweed. Even though Duckweed itself has no known interaction with Sevelamer, 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 Duckweed and Sevelamer 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 Duckweed
Steady interest

#1,165 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Sevelamer
Steady interest

#2,021 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. Duckweed is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Duckweed reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Duckweed and Sevelamer records this page draws on were last updated June 22, 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 Duckweed

What is Duckweed?

  • Plant-based protein source
  • Source of vitamins and minerals
  • Traditional remedy for fever and inflammation
  • Skin conditions and rashes
  • General nutrition and wellness

Duckweed is a tiny floating water plant being studied as a nutrient-dense, plant-based protein and food source. Human evidence for any specific health benefit is very limited, and safety depends heavily on the plant being grown in clean, uncontaminated water. Talk to a pharmacist or doctor before using it as a supplement.

Lemnaceae · Whole plant (fronds) · Powder, capsules, tablets, dried whole plant, protein supplements, traditional decoctions

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

Duckweed: dosing

There is no official, standardized dose for duckweed supplements. The right amount has not been established in clinical research, and products vary widely in concentration and form.If you choose to use a duckweed product, follow the directions on the label and do not exceed the recommended amount.

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

Read the full Duckweed monograph & all interactions
Medication

About Sevelamer

What Is Sevelamer Used For?

Brand name: Renagel

Sevelamer is used to control serum phosphorus (the level of phosphorus in your blood) in people with chronic kidney disease (CKD) who are on dialysis. High phosphorus is a serious problem for dialysis patients and needs to be managed with medication and diet.

Sevelamer carbonate tablets and Renvela® (sevelamer carbonate) oral suspension are approved for adults and children 6 years of age and older. Sevelamer hydrochloride tablets are indicated for adults with CKD on dialysis; their safety and effectiveness in CKD patients not on dialysis have not been studied.

See full Sevelamer drug information
Keep checking

Other Drugs & Duckweed

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Duckweed list.

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

Duckweed References

The 2 sources that drive our Duckweed monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Duckweed is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Dietary Supplements: What You Need to Know — NIH Office of Dietary Supplements Source
  2. Using Dietary Supplements Wisely — NIH NCCIH Source

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 Duckweed and Sevelamer Together: Common Questions

Is it safe to take Duckweed with Sevelamer?
We do not list a known interaction between Duckweed and Sevelamer. 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.
Should I take Duckweed and Sevelamer at the same time of day?
At least one FDA label for a product containing Sevelamer says to take it with food. If you take Duckweed on an empty stomach out of habit, keep them separate and take Sevelamer with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Sevelamer products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Sevelamer interact with any supplements?
Yes. Sevelamer has documented interactions with 18 supplements in our database — Duckweed is not one of them. The Sevelamer 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

Duckweed monograph Uses, safety profile, and every drug interaction in one place Sevelamer drug information The full plain-English guide to this medication Sevelamer supplement interactions Every supplement checked against Sevelamer, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Sevelamer and Duckweed?

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.