herb · for acne
Saw Palmetto
Meant to block the hormone signal that drives oil production in the skin.
Say that in clinical terms
Blocks androgen receptors and 5-alpha reductase, reducing sebum production and sebaceous gland activity.
How strong is the research?
1 paper read.
Who was studied: Adult women with acne, which is a good match — but the cited study could not be confirmed.
No human clinical trial, RCT, cohort study, or case report series has tested Serenoa repens (saw palmetto) specifically for acne treatment or sebum reduction. PubMed searches for 'Serenoa repens sebum' and 'saw palmetto acne clinical trial' each return zero results. We cannot stand behind this claim on the evidence we have, so it carries no rating.
How much to take
daily
160–320 mg
May take 4-6 weeks to see effects. More effective in hormonal acne.
Before you take it
- No Tolerable Upper Intake Level (UL) has been established by NIH ODS for saw palmetto (Serenoa repens) — it is a botanical extract, not a nutrient with a defined UL.
- Contraindicated in pregnancy and lactation: 5-alpha reductase (5-AR) inhibition may disrupt androgen-dependent fetal development; saw palmetto is effectively Category X in pregnancy.
- Case reports document increased bleeding risk in patients co-administering anticoagulants (warfarin) or antiplatelet agents; the proposed mechanism is antiplatelet activity from fatty acid constituents. Clinical significance is debated but co-administration warrants caution.
- May reduce efficacy of exogenous hormonal therapies — including oral contraceptives, testosterone replacement, HRT, and co-prescribed anti-androgens (spironolactone, cyproterone) — by competing for the same androgenic pathway.
- 5-AR inhibition suppresses PSA values; men taking saw palmetto may show false-low PSA results, potentially obscuring early prostate cancer detection.
- Rare case reports of cholestatic hepatitis have been associated with saw palmetto; the causal relationship is unconfirmed but hepatotoxicity is a recognized rare adverse event.
- Most common adverse effects are GI-related (nausea, diarrhea, constipation, abdominal discomfort); generally mild and transient at standard doses.
- In vitro inhibition of CYP2C9, CYP2C19, and CYP3A4 has been observed at supratherapeutic concentrations; no clinically confirmed pharmacokinetic drug-drug interactions have been demonstrated at standard doses (160–320 mg/day).
- The primary demographic for hormonal acne treatment (women of reproductive age) substantially overlaps with the pregnancy contraindication for saw palmetto — this clinical overlap is particularly salient for this indication and warrants explicit disclosure at point of recommendation.
When to take it
Best taken: with food
What we make of it
The paper we cite is about hair-pulling disorder and has nothing to do with saw palmetto.
The detail
The citation resolves to a 2019 paper on trichotillomania — a hair-pulling disorder. It contains no saw palmetto, no acne and no hormone content whatsoever. This needs a real source before anything can be said.