Drug & supplement interaction

Agar + Progesterone

Progesterone brand name: Milprosa.

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 Agar and Progesterone 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.

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Interaction report

Agar and Progesterone

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 Progesterone and Agar 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.

Agar safety at a glance

Agar overall Use caution Generally safe as a food, but supplement doses should be taken with plenty of water to avoid blockage.
Pregnancy Use caution Likely fine in normal food amounts, but avoid concentrated supplement doses unless your doctor approves.
Breastfeeding Use caution Food amounts are likely fine, but there is little safety data on supplement doses.

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

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

Why No Interaction Is Listed for Progesterone

Interactions in our licensed database are recorded against drug classes, not just single drug names. Progesterone is filed under 3 classifications — including topical drugs, cytochrome p450 3a4 (cyp3a4) substrates. Agar has documented interactions with 1 drug class — the most serious being oral drugs (minor) — and none of Progesterone’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

Agar Does Interact With Other Medications

Agar has 2,022 minor known drug interactions in our database — Progesterone isn’t one of them. If you take anything else, check it against the full list below.

Minor 2,022 No known interaction 808 (incl. Progesterone)
Taking anything else?

Check Another of Your Medications Against Agar

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

What to actually watch for

What Agar Itself Has Been Linked To

This is not an interaction — nothing below involves Progesterone. It is the side-effect record for Agar on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Agar, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • A bowel blockage Worth acting on Additional detail

    “Orally, no adverse effects have been reported; however, a thorough evaluation of safety outcomes has not been conducted. Rarely, phytobezoars and esophageal or bowel obstruction have been reported after ingestion of high-fiber foods, such as agar (12,30500).”

    Agar · Natural Medicines adverse-effect record, reported in bowel obstruction.

    2 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 30500. Osada, T., Shibuya, T., Kodani, T., Beppu, K., Sakamoto, N., Nagahara, A., Ohkusa, T., Ogihara, T., and Watanabe, S. Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy. Intern.Med 2008;47(7):617-620. PubMed

    “Orally, phytobezoars, which are concentrations of fruit and vegetable fibers in the gastrointestinal tract, have been rarely reported following ingestion of high-fiber foods, such as agar. Esophageal or bowel obstruction has also been reported when agar is consumed without sufficient fluid intake (12).”

    Agar · Natural Medicines adverse-effect record, reported in bowel obstruction.

    2 sources cited
    1. 30500. Osada, T., Shibuya, T., Kodani, T., Beppu, K., Sakamoto, N., Nagahara, A., Ohkusa, T., Ogihara, T., and Watanabe, S. Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy. Intern.Med 2008;47(7):617-620. PubMed
    2. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.

Everything above comes from the Natural Medicines adverse-effect record for Agar — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Progesterone’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Progesterone column appears here.

From our Q&A

Questions About Agar or Progesterone

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

This page covers Agar only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Progesterone page lists 126 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 91 moderate · 33 minor.

From our pharmacist’s overview on the Progesterone page

“Many people take progesterone (Milprosa) to support a pregnancy during fertility treatment or as part of hormone therapy, which is exactly when St. John's wort for mood or a morning glass of grapefruit juice can feel harmless.”

Reviewed by 2 · Jul 18, 2026

Open the Progesterone interaction page

One more smart check

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

We hold 23 real supplement products containing Agar, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Agar. Even though Agar itself has no known interaction with Progesterone, 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 Agar and Progesterone 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 Agar
Top half

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

29 days ago today
Medication Progesterone
Top 10%

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

What is Agar?

Agar
  • Constipation
  • Weight loss
  • Vegetarian gelatin substitute
  • Source of dietary fiber
  • Appetite control

Agar is a plant-based gel made from red seaweed that is widely used as a vegetarian alternative to gelatin and as a source of dietary fiber. It is sometimes taken as a bulk-forming laxative or weight-loss aid, but solid human evidence for these health uses is limited. It is generally considered safe as a food, but you should drink plenty of water with it and check with your pharmacist before using it as a supplement.

Cell wall extract of red algae (seaweed) · Powder, flakes, bars, capsules, food-grade gel

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

Agar: dosing

There is no official, well-established medical dose of agar. The amount used in cooking depends on the recipe, and supplement products vary widely.If you use an agar supplement, follow the directions on the product label and take it with plenty of water.

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

Read the full Agar monograph & all interactions
Medication

About Progesterone

What Is Progesterone Used For?

Brand name: Milprosa

Progesterone capsules (including Prometrium) are used to prevent endometrial hyperplasia (abnormal thickening of the uterine lining) in postmenopausal women with a uterus who are taking estrogen, and to treat secondary amenorrhea (missed periods not caused by pregnancy).

Progesterone injection is indicated for amenorrhea and abnormal uterine bleeding caused by a hormonal imbalance. Crinone vaginal gel is used as part of Assisted Reproductive Technology (ART) for progesterone supplementation or replacement, and Crinone 4% is also indicated for secondary amenorrhea. Vaginal inserts — including Endometrin and other progesterone vaginal insert products — are used to support embryo implantation and early pregnancy as part of an ART treatment program for infertile women.

Most-Reported Side Effects for Progesterone

From FAERS, the FDA’s public side-effect reporting system (22,803 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Headache 2,094 reports
Fatigue 1,795 reports
Nausea 1,475 reports
Rash 984 reports
Dizziness 941 reports
See full Progesterone drug information
Keep checking

Other Drugs & Agar

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

0Major
0Moderate
2,022Minor
807No known interaction
2,022 Minor 807 No interaction
Minor

2,022 interactions

Showing 60 of 2,022 minor interactions — see all 2,022 on the Agar page.

No interaction 807 drugs checked — show the list

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

Showing the 60 most looked-up of 807 medications checked with no known interaction — see the full Agar list.

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

Agar References

The 13 references that drive our Agar 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Kondo H, Osada A. Influence of dietary fiber on the bioavailability of zinc in rats. Biomed Environ Sci. 1996 Sept;9(2-3):204-8.
  4. Romagnoli, C., Polidori, G., Foschini, M., Cataldi, L., De, Turris P., Tortorolo, G., and Mastrangelo, R. Agar in the management of hyperbilirubinaemia in the premature baby. Arch.Dis.Child 1975;50(3):202-204. PubMed
  5. Windorfer, A., Jr., Kunzer, W., Bolze, H., Ascher, K., Wilcken, F., and Hoehne, K. Studies on the effect of orally administered agar on the serum bilirubin level of premature infants and mature newborns. Acta Paediatr.Scand. 1975;64(5):699-702. PubMed
  6. Maeda, H., Yamamoto, R., Hirao, K., and Tochikubo, O. Effects of agar (kanten) diet on obese patients with impaired glucose tolerance and type 2 diabetes. Diabetes Obes.Metab 2005;7(1):40-46.
  7. Osada, T., Shibuya, T., Kodani, T., Beppu, K., Sakamoto, N., Nagahara, A., Ohkusa, T., Ogihara, T., and Watanabe, S. Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy. Intern.Med 2008;47(7):617-620. PubMed
  8. Kemper, K., Horwitz, R. I., and McCarthy, P. Decreased neonatal serum bilirubin with plain agar: a meta-analysis. Pediatrics 1988;82(4):631-638. DOI
  9. Meloni, T., Costa, S., Corti, R., and Cutillo, S. Agar in control of hyperbilirubinemia of full-term newborn infants with erythrocyte G-6-PD deficiency. Biol.Neonate 1978;34(5-6):295-298. PubMed
  10. Maurer, H. M., Shumway, C. N., Draper, D. A., and Hossaini, A. A. Controlled trial comparing agar, intermittent phototherapy, and continuous phototherapy for reducing neonatal hyperbilirubinemia. J Pediatr. 1973;82(1):73-76.
  11. Caglayan, S., Candemir, H., Aksit, S., Kansoy, S., Asik, S., and Yaprak, I. Superiority of oral agar and phototherapy combination in the treatment of neonatal hyperbilirubinemia. Pediatrics 1993;92(1):86-89. DOI
  12. Harmuth-Hoene, A. E. and Schelenz, R. Effect of dietary fiber on mineral absorption in growing rats. J Nutr 1980;110(9):1774-1784. PubMed
  13. Abdel-Aziz Ali SMA, Mansour Galal S, Sror SM, Hussein O, Abd-El-Haseeb Ahmed AO, Hamed EA. Efficacy of oral agar in management of indirect hyperbilirubinemia in full-term neonates. J Matern Fetal Neonatal Med. 2020:1-6. 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 Agar and Progesterone Together: Common Questions

Is it safe to take Agar with Progesterone?
We do not list a known interaction between Agar and Progesterone. 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.
How was the Agar and Progesterone combination checked?
Interactions in our licensed database are recorded against drug classes. Progesterone is filed under 3 classifications, and Agar has documented interactions with 1 drug class — none of Progesterone'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 Agar interact with any other medications?
Yes. Agar has 2,022 documented drug interactions in our database — Progesterone 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 Progesterone interact with any supplements?
Yes. Progesterone has documented interactions with 126 supplements in our database — Agar is not one of them. The Progesterone 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

Agar monograph Uses, safety profile, and every drug interaction in one place Progesterone drug information The full plain-English guide to this medication Progesterone supplement interactions Every supplement checked against Progesterone, 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 13 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Progesterone and Agar?

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.