Drug & supplement interaction

Saw Palmetto + Mannitol

Mannitol brand names: Osmitrol, Bronchitol.

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 Saw Palmetto and Mannitol 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Saw Palmetto and Mannitol

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 Mannitol and Saw Palmetto 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.

Saw Palmetto safety at a glance

Saw Palmetto overall Use caution Generally well tolerated in adults but should be used under guidance, especially for prostate or urinary symptoms.
Pregnancy Likely Unsafe When used orally. Saw palmetto has hormonal activity; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally. Saw palmetto has hormonal activity; avoid using. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Pharmacist analysis

-----

On the whole, saw palmetto has very few reported drug interactions due to its lack of effects on liver metabolizing enzymes (e.g., CYP P450 enzymes).

There have been some reports of minor interactions with anticoagulants, estrogens, and contraceptives due to saw palmetto's purported effects on blood clotting and various hormones in the body. However, these interactions have generally only been seen in lab studies and for most individuals, are not considered clinically significant.

As always, however, be sure to talk to your doctor before starting any new medications or supplements so you can be appropriately monitored.

Comprehensive analysis does not indicate a significant interaction.

—

Still wondering about combining Mannitol and Saw Palmetto? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Mannitol

Interactions in our licensed database are recorded against drug classes, not just single drug names. Mannitol is filed under 3 classifications — diuretic drugs, antihypertensive drugs, oral drugs. Saw Palmetto has documented interactions with 3 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), contraceptive drugs (moderate) and estrogens (moderate) — and none of Mannitol’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

Saw Palmetto Does Interact With Other Medications

Saw Palmetto has 174 moderate known drug interactions in our database — Mannitol isn’t one of them. If you take anything else, check it against the full list below.

Moderate 174 No known interaction 2,656 (incl. Mannitol)
Taking anything else?

Check Another of Your Medications Against Saw Palmetto

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

What to actually watch for

No Interaction Found — But Data Suggests Saw Palmetto and Mannitol 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Chest pain Worth acting on Additional detail

    Saw Palmetto

    “Occasionally, cases of hypertension, postural hypotension, tachycardia, angina pectoris, arrhythmia, extrasystole, angiopathy, myocardial infarction, and congestive heart failure have been reported in patients using saw palmetto orally. One case of severe bradycardia and second degree heart block was reported in a 64 year-old male taking an unknown amount of saw palmetto for a few weeks.”

    Saw Palmetto · Natural Medicines adverse-effect record, reported in angina.

    1 source cited
    1. 96413. Jipescu D, Patel A, Bohra H, Pientka A. Rare case of saw palmetto induced heart block. JACC 2017;69(11) supplement:2310.

    Mannitol

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

  • Shortness of breath Worth acting on Additional detail

    Saw Palmetto

    “Rhinitis is one of the more commonly reported adverse effects of saw palmetto. One patient taking saw palmetto extract 160 mg twice daily reported "breathlessness". Two cases of respiratory depression have been reported in patients using saw palmetto extract (Permixon) 320 mg.”

    Saw Palmetto · Natural Medicines adverse-effect record, reported in depression.

    3 sources cited
    1. 73348. Agbabiaka, T. B., Pittler, M. H., Wider, B., and Ernst, E. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf 2009;32(8):637-647. PubMed
    2. 73388. Braeckman J. The extract of Serenoa repens in the treatment of benign prostatic hyperplasia: a multicenter open study. Current Therapeutic Research 1994;55(7):776-785. DOI
    3. 6772. Stepanov VN, Siniakova LA, Sarrazin B, Raynaud JP. Efficacy and tolerability of the lipidosterolic extract of Serenoa repens (Permixon) in benign prostatic hyperplasia: a double-blind comparison of two dosage regimens. Adv Ther 1999;16:231-41.

    Mannitol

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

  • Dizziness / Headache Additional detail

    Saw Palmetto

    “Orally, saw palmetto can cause headaches, dizziness, insomnia, and fatigue.”

    Saw Palmetto · Natural Medicines adverse-effect record, reported in fatigue.

    Mannitol

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

  • Vomiting / Nausea Additional detail

    Saw Palmetto

    “Gastrointestinal complaints such as nausea, vomiting, constipation, diarrhea, gastralgia, and halitosis are the most frequently reported adverse effects associated with saw palmetto. Less often, cases of duodenal ulcer, dyspepsia, or heartburn have been reported. Meteorism (intestinal gas accumulation) has also been reported with saw palmetto, although causality was unclear.”

    Saw Palmetto · Natural Medicines adverse-effect record, reported in constipation.

    4 sources cited
    1. 6772. Stepanov VN, Siniakova LA, Sarrazin B, Raynaud JP. Efficacy and tolerability of the lipidosterolic extract of Serenoa repens (Permixon) in benign prostatic hyperplasia: a double-blind comparison of two dosage regimens. Adv Ther 1999;16:231-41.
    2. 73329. Aliaev, IuG, Vinarov, A. Z., Lokshin, K. L., and Spivak, L. G. [Efficiency and safety of prostamol-Uno in patients with chronic abacterial prostatitis]. Urologiia. 2006;(1):47-50.
    3. 73354. Mantovani, F. Serenoa repens in benign prostatic hypertrophy: analysis of 2 Italian studies. Minerva Urol.Nefrol. 2010;62(4):335-340.
    4. 60442. Morgia, G., Mucciardi, G., Gali, A., Madonia, M., Marchese, F., Di, Benedetto A., Romano, G., Bonvissuto, G., Castelli, T., Macchione, L., and Magno, C. Treatment of chronic prostatitis/chronic pelvic pain syndrome category IIIA with Serenoa repens plus

    Mannitol

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

Reported for Saw Palmetto but not commonly for Mannitol: heart failure, a heart attack, low blood pressure and erection problems.

Effects for Mannitol come from the ADVERSE REACTIONS section of its FDA label; effects for Saw Palmetto come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 4,912 voluntary FDA FAERS reports for Mannitol 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.

Special populations

Saw Palmetto in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally. Saw palmetto has hormonal activity; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Saw Palmetto or Mannitol

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

This page covers Saw Palmetto only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mannitol page lists 200 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Lithium (major) and Oleander (major).

By severity: 7 major · 169 moderate · 24 minor.

From our pharmacist’s overview on the Mannitol page

“American hellebore tops my worry list for anyone on mannitol (Osmitrol, Bronchitol), an osmotic diuretic used to draw fluid off the brain or, when inhaled, to clear mucus in cystic fibrosis. The plant's alkaloids drop blood pressure and slow the heart, a dangerous match for a drug that already shifts fluid and pressure quickly.”

Reviewed by 2 · Jul 18, 2026

Open the Mannitol interaction page

One more smart check

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

We hold 3,466 real supplement products containing Saw Palmetto, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Saw Palmetto. Even though Saw Palmetto itself has no known interaction with Mannitol, 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 Saw Palmetto and Mannitol 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 Saw Palmetto
Top 10%

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

29 days ago today
Medication Mannitol
Top 25%

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

What is Saw Palmetto?

Saw Palmetto
  • Benign prostatic hyperplasia (BPH) symptoms
  • Urinary problems
  • Hair loss
  • Prostate health
  • Inflammation

Saw palmetto is a plant extract most often used for urinary symptoms linked to an enlarged prostate (BPH). The best research suggests it works no better than a placebo for most men, though it is generally well tolerated. Talk to your doctor or pharmacist before using it, especially for prostate or urinary problems that need proper evaluation.

Serenoa repens · Arecaceae · Fruit (berries) · Capsules, softgels, tablets, liquid extracts, dried berries, tea

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

Saw Palmetto: dosing

There is no official, agreed-upon dose for saw palmetto. Products vary in strength and how they are prepared, and many are standardized to a certain percentage of fatty acids.The safest approach is to follow the dosing directions on the product label and not exceed them. They can help you decide whether it is appropriate and what dose is reasonable for you.

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

Read the full Saw Palmetto monograph & all interactions
Medication

About Mannitol

Most-Reported Side Effects for Mannitol

From FAERS, the FDA’s public side-effect reporting system (4,912 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Renal failure 592 reports
Anxiety 505 reports
Injury 495 reports
Unevaluable event 470 reports
Stress 463 reports
Keep checking

Other Drugs & Saw Palmetto

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

0Major
174Moderate
0Minor
2,655No known interaction
174 Moderate 2,655 No interaction
Moderate

174 interactions

Showing 60 of 174 moderate interactions — see all 174 on the Saw Palmetto page.

No interaction 2,655 drugs checked — show the list

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

Showing the 60 most looked-up of 2,655 medications checked with no known interaction — see the full Saw Palmetto list.

See the full Saw Palmetto interactions page
See every supplement checked against Mannitol, ranked by severity
Evidence & sources

Saw Palmetto References

The 22 references that drive our Saw Palmetto 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. Wilt TJ, Ishani A, Stark G, et al. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA 1998;280:1604-9. PubMed
  2. Carraro JC, Raynaud JP, Koch G, et al. Comparison of phytotherapy (Permixon) with finasteride in the treatment of benign prostate hyperplasia: a randomized international study of 1,098 patients. Prostate 1996;29:231-40. DOI
  3. Di Silverio F, D'Eramo G, Lubrano C, et al. Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients. Eur Urol 1992;21:309-14. PubMed
  4. Stepanov VN, Siniakova LA, Sarrazin B, Raynaud JP. Efficacy and tolerability of the lipidosterolic extract of Serenoa repens (Permixon) in benign prostatic hyperplasia: a double-blind comparison of two dosage regimens. Adv Ther 1999;16:231-41.
  5. Cheema P, El-Mefty O, Jazieh AR. Intraoperative haemorrhage associated with the use of extract of Saw Palmetto herb: a case report and review of literature. J Intern Med 2001;250:167-9. PubMed
  6. Jibrin I, Erinle A, Saidi A, Aliyu ZY. Saw palmetto-induced pancreatitis. South Med J 2006;99:611-2. PubMed
  7. Prager N, Bickett K, French N, Marcovici G. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. J Altern Complement Med 2002
  8. Avins AL, Bent S, Staccone S, et al. A detailed safety assessment of a saw palmetto extract. Complement Ther Med 2008;16:147-54. PubMed
  9. Morgia, G., Mucciardi, G., Gali, A., Madonia, M., Marchese, F., Di, Benedetto A., Romano, G., Bonvissuto, G., Castelli, T., Macchione, L., and Magno, C. Treatment of chronic prostatitis/chronic pelvic pain syndrome category IIIA with Serenoa repens plus
  10. Aliaev, IuG, Vinarov, A. Z., Lokshin, K. L., and Spivak, L. G. [Efficiency and safety of prostamol-Uno in patients with chronic abacterial prostatitis]. Urologiia. 2006;(1):47-50.
  11. Agbabiaka, T. B., Pittler, M. H., Wider, B., and Ernst, E. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf 2009;32(8):637-647. PubMed
  12. Wargo, K. A., Allman, E., and Ibrahim, F. A possible case of saw palmetto-induced pancreatitis. South.Med.J. 2010;103(7):683-685. PubMed
  13. Lapi, F., Gallo, E., Giocaliere, E., Vietri, M., Baronti, R., Pieraccini, G., Tafi, A., Menniti-Ippolito, F., Mugelli, A., Firenzuoli, F., and Vannacci, A. Acute liver damage due to Serenoa repens: a case report. Br.J.Clin.Pharmacol. 2010;69(5):558-560.
  14. Mantovani, F. Serenoa repens in benign prostatic hypertrophy: analysis of 2 Italian studies. Minerva Urol.Nefrol. 2010;62(4):335-340.
  15. Hanaka, M., Yoshii, C., Yatera, K., Ito, C., Chojin, Y., Nagata, S., Yamasaki, K., Nishida, C., Kawanami, T., Kawanami, Y., Ishimoto, H., and Mukae, H. [A case of rhabdomyolysis caused by saw palmetto of healthy foods]. J.UOEH. 6-1-2012;34(2):193-199. 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 Saw Palmetto and Mannitol Together: Common Questions

Is it safe to take Saw Palmetto with Mannitol?
We do not list a known interaction between Saw Palmetto and Mannitol. 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 Saw Palmetto and Mannitol have any of the same side effects?
Yes — our sources link each of them separately to 6 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 Saw Palmetto and Mannitol combination checked?
Interactions in our licensed database are recorded against drug classes. Mannitol is filed under 3 classifications, and Saw Palmetto has documented interactions with 3 drug classes — none of Mannitol'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 Saw Palmetto interact with any other medications?
Yes. Saw Palmetto has 174 documented drug interactions in our database — Mannitol 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 Mannitol interact with any supplements?
Yes. Mannitol has documented interactions with 200 supplements in our database — Saw Palmetto is not one of them. The Mannitol 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

Saw Palmetto monograph Uses, safety profile, and every drug interaction in one place Mannitol supplement interactions Every supplement checked against Mannitol, 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 22 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Mannitol and Saw Palmetto?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.