Quick answer: finasteride is the more powerful option — it lowers DHT by roughly 60–70% and is backed by large clinical trials, but it's prescription-only in the UK and carries a known risk of side effects. Saw palmetto is gentler and available without prescription, with smaller studies suggesting a more modest effect. Which suits you depends on how you weigh strength against side-effect risk.
Full disclosure before we go further: HerbiCure sells a saw palmetto and pumpkin seed oil supplement, so we clearly have a horse in this race. That's exactly why this guide cites the research for both options, including the parts that don't flatter us.
How they both work: the DHT connection
Both approaches target the same mechanism. Dihydrotestosterone (DHT) is a hormone linked to the gradual miniaturisation of hair follicles in pattern hair loss. Your body converts testosterone into DHT using an enzyme called 5-alpha reductase. Finasteride and saw palmetto both aim to inhibit that enzyme — they just do it with very different force.
What the research says about finasteride
Finasteride (1mg daily) is a licensed medicine for male pattern hair loss with decades of trial data behind it. Studies show it reduces serum DHT by around 60–70%, and long-term trials report that most men maintain or improve their hair count on it. In a two-year Italian study comparing the two head-to-head (Rossi et al., 2012), 68% of men taking finasteride saw improvement, versus 38% of those taking 320mg of saw palmetto daily.
That's the honest headline: in the only direct comparison we have, finasteride won. It is the stronger intervention, and any supplement company that tells you otherwise is not being straight with you.
What the research says about saw palmetto
Saw palmetto is a berry extract that appears to partially inhibit the same 5-alpha reductase enzyme, with estimates suggesting a DHT reduction in the region of 30–40% — roughly half of finasteride's effect. A 2020 systematic review in the journal Skin Appendage Disorders (Evron et al.) looked at seven studies of oral and topical saw palmetto in people with androgenetic alopecia and telogen effluvium. It reported a 60% improvement in overall hair quality, a 27% improvement in total hair count, and stabilised progression in 52% of participants.
Worth knowing: the studies are smaller and shorter than finasteride's, and saw palmetto is not endorsed by NICE or any major UK hair loss guideline. The evidence is promising rather than proven.
The side-effect picture
This is where the comparison flips. Finasteride's strength comes with documented risks: a minority of men report sexual side effects (reduced libido, erectile difficulties), and some report low mood. Most men tolerate it fine, but the risk is real enough that it's a prescription-only medicine in the UK, and women of childbearing age are advised not to handle crushed tablets at all.
Saw palmetto's side-effect profile in studies has been mild — occasional digestive upset is the most commonly reported issue. That gentler profile, and the fact that it has also been studied in women, is the main reason people choose the natural route despite the weaker effect.
Head to head
| Finasteride | Saw palmetto | |
|---|---|---|
| DHT reduction | ~60–70% | ~30–40% (estimated) |
| Evidence base | Large, long-term licensed-medicine trials | Smaller studies and one systematic review |
| UK access | Prescription only | Available as a food supplement |
| Reported side effects | Sexual side effects and mood changes in a minority | Generally mild (occasional digestive upset) |
| Studied in women | Not licensed for women in the UK | Yes, in mixed-sex studies |
So which should you choose?
If your hair loss is progressing quickly and you want the strongest evidence-backed option, talk to your GP or a pharmacist prescriber about finasteride. That's the medically established path, and no supplement honestly replaces it.
If your shedding is milder, you're not comfortable with finasteride's side-effect profile, or you're a woman (for whom finasteride isn't licensed in the UK), a saw palmetto supplement is the most-studied natural alternative. Some people also pair saw palmetto with pumpkin seed oil, another botanical with its own randomised trial — we've broken that down in our pumpkin seed oil vs saw palmetto guide and our review of the pumpkin seed oil research.
Whichever route you take, commit to it properly: hair cycles are slow, and the studies above ran for six months to two years. Judging anything at week four tells you nothing.
FAQs
Can I take saw palmetto and finasteride together?
They act on the same enzyme, so combining them is a question for your prescriber — don't stack them on your own initiative.
Does saw palmetto have the same sexual side effects as finasteride?
Studies to date report a milder profile, with digestive upset the most common complaint. Absence of evidence isn't proof of absence, but the reported rates are lower.
How long does saw palmetto take to show anything?
The studies in the 2020 review typically ran 12–24 weeks minimum. Consistency matters more than dose-chasing.
Is saw palmetto safe for women?
It has been studied in women with thinning hair, unlike finasteride. Avoid it if pregnant or breastfeeding, and check with your GP if you take hormonal medication.
This article is for information only and is not medical advice. Saw palmetto is a food supplement, not a medicine — it is not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the MHRA. Individual results vary. Speak to your GP or pharmacist before starting any supplement or medicine, particularly if you have a medical condition or take medication.