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ingestible · for hair thinning & hair loss

Saw Palmetto

Reviewed by the Nimbera editorial team · Last updated May 2026

A 2020 systematic review (PMC7706486) of 9 studies (n=381) found saw palmetto at 100-320 mg/day produced 27% improvement in hair count and 60% improvement in hair quality across trials. In a head-to-head RCT vs finasteride 1 mg/day over 2 years, 38% of saw palmetto users showed improved hair density vs 68% with finasteride - saw palmetto is inferior to prescription therapy but shows meaningful activity.$15-$35 per month for a quality standardized extract

How to use

Take 160-320 mg of saw palmetto extract (standardized to 85-95% fatty acids and sterols) twice daily with food. Lipophilic extracts in softgel form are better absorbed than powdered forms. Allow a minimum of 3-6 months of consistent daily use before assessing results. Available as oral capsules and as topical scalp serums.

How it works

Saw palmetto (Serenoa repens) inhibits 5-alpha-reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT). DHT binds to androgen receptors in scalp hair follicles and progressively miniaturizes them in pattern hair loss. By reducing DHT conversion, saw palmetto works through the same primary mechanism as prescription finasteride (Propecia), but with weaker inhibitory potency and without the systemic hormonal side effects associated with finasteride.

Where to buy

Pharmacies, health food stores, and online. Look for standardized lipophilic extract (85-95% fatty acids). Brands: Jarrow Formulas Saw Palmetto, Nature's Way Standardized Saw Palmetto. Ensure the product specifies fatty acid content rather than just raw berry powder.

Typical cost: $15-$35 per month for a quality standardized extract

Safety notes

Saw palmetto may interact with anticoagulant and antiplatelet medications (warfarin, aspirin, clopidogrel) by inhibiting platelet aggregation - monitor for increased bleeding risk and inform your prescriber. May interfere with hormone therapies including estrogen, oral contraceptives, and testosterone replacement - consult your physician if you are on any hormonal treatment. Gastrointestinal side effects (nausea, diarrhea, headache) occur in some users. Do not use during pregnancy or breastfeeding. Although saw palmetto and finasteride share the same mechanism (5AR inhibition), concurrent use is not well studied; discuss with a physician.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Evron E et al. Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia. Skin Appendage Disord. 2020.

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.