What are the side effects of Serenoa repens (saw palmetto)?

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Last updated: March 13, 2025View editorial policy

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From the Guidelines

Saw palmetto supplements may cause bleeding complications due to their potential effect on hemostasis, although the evidence is conflicting 1. The side effects of Serenoa repens, commonly known as saw palmetto, can vary and may include:

  • Gastrointestinal symptoms such as nausea, vomiting, constipation, and diarrhea
  • Hormonal effects, including decreased libido or erectile dysfunction, and potential breast tenderness or enlargement in men due to its impact on DHT levels
  • Interactions with certain medications, particularly those affecting hormone levels or blood thinners like warfarin Key considerations for saw palmetto use include:
  • Discontinuing the supplement 1 to 2 weeks before surgery to minimize the risk of bleeding complications, as recommended by the American Society of Anesthesiology 1
  • Avoiding use in people with hormone-sensitive conditions, those scheduled for surgery, pregnant or breastfeeding women, and children
  • Monitoring for potential interactions with other medications, especially blood thinners and oral contraceptives It is essential to note that the evidence on saw palmetto's side effects, particularly regarding bleeding complications, is conflicting, and more research is needed to fully understand its effects 1. However, as a precautionary measure, it is recommended to discontinue saw palmetto supplements before surgery and to consult a healthcare provider if any side effects occur.

From the Research

Side Effects of Serenoa Repens (Saw Palmetto)

The side effects of Serenoa repens (saw palmetto) have been studied in various research papers. Some of the reported side effects include:

  • Abdominal pain 2
  • Diarrhea 2
  • Nausea 2, 3
  • Fatigue 2
  • Headache 2
  • Decreased libido 2
  • Rhinitis 2
  • Acute pancreatitis 3, 4

Serious Adverse Events

Some studies have reported serious adverse events associated with the use of saw palmetto, including:

  • Acute pancreatitis 3, 4
  • Cerebral haemorrhage 2
  • Death 2

Drug Interactions

There is limited evidence on drug interactions with saw palmetto. One study found no evidence for drug interactions with saw palmetto 2.

Safety Assessment

A detailed safety assessment of a saw palmetto extract found no significant differences in the risk of suffering at least one serious adverse event or non-serious symptomatic adverse event compared to a placebo 5. Another study found that saw palmetto at 960 mg may be a safe herbal supplement, but its efficacy in managing lower urinary tract symptoms during radiation therapy needs further investigation 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acute pancreatitis with saw palmetto use: a case report.

Journal of medical case reports, 2011

Research

A possible case of saw palmetto-induced pancreatitis.

Southern medical journal, 2010

Research

A detailed safety assessment of a saw palmetto extract.

Complementary therapies in medicine, 2008

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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