Saw palmetto
Herbal products and dietary supplements
Herbal products and dietary supplementsPregnancy: avoid
Avoid in pregnancy. It may be unsafe in pregnancy or breastfeeding.
Berry extract of Serenoa repens, promoted for urinary symptoms of an enlarged prostate. Trials show little or no benefit; it is well tolerated.
Also called: Serenoa repens, Sabalis serrulatae fructus
Quick facts
- Group
- Herbal products and dietary supplements
- Target
- 5-alpha reductase (inhibited in vitro only)
- Used for
- Promoted for urinary symptoms
- Key effects
- Digestive symptoms · Dizziness · Headache
- Monitor
- Urinary symptoms · PSA is not affected
- ATC
- G04CX02
No doses: the clinician sets them by the current guideline.
Mechanism of action
In laboratory studies saw palmetto extract inhibits 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT), the same step blocked by finasteride. Studies in men with benign prostatic hyperplasia have not consistently shown lower DHT or enzyme inhibition, which fits the lack of clinical benefit.
- Berry extract is taken by mouth
- 5-alpha reductase is inhibited in vitro
- In men, DHT and symptoms change little or not at all
Indications
- Promoted for urinary symptoms of benign prostatic hyperplasia: probably not helpful when used alone Benign prostatic hyperplasia →
Adverse effects
Common
- Digestive symptoms
- Dizziness
- Headache
Contraindications
- No established contraindications; see the precautions
Key interactions
- Any regular medicines
- No specific interactions are well documented; product content varies
What is monitored
- Urinary symptoms and standard prostate evaluation
- PSA is not affected, so it remains interpretable
Pregnancy and breastfeeding
Avoid in pregnancy. It may be unsafe in pregnancy or breastfeeding.
Nursing care
- Ask every patient about herbal products and supplements and record them with the medicine list
- Encourage evaluation of new urinary symptoms rather than self-treatment
- Teach that «natural» does not mean safe and that supplements are not approved as medicines before sale
Pharmacokinetics
- Absorption
- Taken by mouth as berry extracts
Test yourself
Think of the answer, then tap the question to see it.
Which enzyme does saw palmetto inhibit in laboratory studies?
5-alpha reductase, the enzyme blocked by finasteride.
What did trials show for saw palmetto in benign prostatic hyperplasia?
Little or no improvement in urinary symptoms when used alone.
Does saw palmetto change PSA results?
No, it does not appear to affect PSA.
Connections
← Back to the class: Herbal products and dietary supplements
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Saw Palmetto: Usefulness and Safety (National Center for Complementary and Integrative Health (NCCIH), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.