NutriStack
Finasteride and Saw Palmetto, a caution.
Saw palmetto (Serenoa repens) has antiandrogenic and 5-alpha-reductase-related activity, overlapping with finasteride therapy for BPH or androgenetic alopecia. A prostate tissue study compared saw palmetto and finasteride effects on prostatic androgens, and a PubMed-indexed case series described persistent sexual and psychiatric symptoms after Serenoa exposure, including combined Serenoa therapies such as finasteride. The concern is additive sexual, mood, or PSA/DHT interpretation effects rather than an acute toxicity syndrome.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Finasteride and Saw Palmetto
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. Saw palmetto (Serenoa repens) has antiandrogenic and 5-alpha-reductase-related activity, overlapping with finasteride therapy for BPH or androgenetic alopecia. A prostate tissue study compared saw palmetto and finasteride effects on prostatic androgens, and a PubMed-indexed case series described persistent sexual and psychiatric symptoms after Serenoa exposure, including combined Serenoa therapies such as finasteride. The concern is additive sexual, mood, or PSA/DHT interpretation effects rather than an acute toxicity syndrome.
Mechanism. Finasteride inhibits type II 5-alpha reductase and lowers dihydrotestosterone. Saw palmetto extracts have been studied for BPH with proposed 5-alpha-reductase and antiandrogenic effects, creating overlapping endocrine and symptom-monitoring effects.
Recommendation. Avoid adding saw palmetto to finasteride unless the prescriber knows you are using both. Tell the clinician interpreting PSA, urinary symptoms, hair-loss response, libido, erectile function, mood, or persistent sexual adverse effects if saw palmetto is started or stopped.
Sources (2)
- Marks LS, Hess DL, Dorey FJ, Macairan ML, Cruz Santos PB, Tyler VE. Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens. Urology. 2001;57(5):999-1005. PMID 11337315
- Can we identify a post-Serenoa syndrome (PSS)? A case series on sexual and psychiatric side effects of Serenoa repens. Br J Clin Pharmacol. 2026 Apr. PMID 41507085
Stack Score
How this pair moves the number.
Effect on the composite score
If both Finasteride and Saw Palmetto are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.