Saw Palmetto for Hair Loss: Does This Natural DHT Blocker Work?
Saw palmetto is the most popular natural DHT blocker for hair loss. Here's what the studies actually say, the right dosage, and how it compares to finasteride.
Saw palmetto is the most talked-about natural alternative to finasteride. It’s cheap, available without a prescription, and claimed to block DHT — the hormone responsible for male pattern baldness.
But does it actually work? And is it worth taking over a proven drug?
Here’s the honest answer, backed by the research.
What Is Saw Palmetto?
Saw palmetto (Serenoa repens) is a small palm plant native to the southeastern United States. Its berries have been used medicinally for centuries.
Its primary active compounds — fatty acids and phytosterols — are believed to inhibit 5-alpha reductase, the enzyme that converts testosterone into DHT (dihydrotestosterone).
Sound familiar? That’s exactly how finasteride works. The difference: finasteride is a pharmaceutical drug with a precise mechanism and strong clinical data. Saw palmetto is a plant extract with weaker but real evidence.
How DHT Causes Hair Loss
Male pattern baldness is driven primarily by DHT binding to androgen receptors in hair follicles. In genetically susceptible men, this causes follicles to progressively miniaturise — producing finer, shorter hairs until they stop producing hair entirely.
Block DHT (or reduce its production), and you slow or stop this process. That’s the logic behind finasteride, dutasteride, and — in a gentler way — saw palmetto.
What Does the Research Say?
The evidence for saw palmetto isn’t as strong as for finasteride, but it’s not nothing either.
Key studies:
2002 — Journal of Alternative and Complementary Medicine: A small study found that 60% of men taking saw palmetto showed improvement in hair loss scores over 21 weeks, compared to 11% in the placebo group. Small sample (26 men), but results were encouraging.
2012 — International Journal of Immunopathology and Pharmacology: This is the most cited study. 100 men with mild-to-moderate androgenetic alopecia took either saw palmetto (320mg/day) or finasteride (1mg/day) for 24 months. Results:
- 38% of saw palmetto users showed improvement
- 68% of finasteride users showed improvement
Finasteride outperformed significantly — but saw palmetto wasn’t useless. More than a third of users saw real improvement.
2020 — Skin Appendage Disorders: A review of multiple studies concluded saw palmetto shows “promising results” for androgenetic alopecia, with a favourable safety profile compared to pharmaceuticals.
2021 — Dermatology and Therapy: A systematic review found saw palmetto to be “mildly effective” for hair loss, particularly in early-stage androgenetic alopecia.
Bottom line from research: Saw palmetto works — but roughly half as effectively as finasteride.
Saw Palmetto vs Finasteride
| Factor | Saw Palmetto | Finasteride |
|---|---|---|
| DHT reduction | ~32% | ~70% |
| Evidence strength | Moderate | Very strong |
| Effectiveness | Mild-moderate | Strong |
| Side effects | Minimal | Sexual side effects in ~2–5% |
| Prescription needed | No | Yes (UK) |
| Monthly cost | £10–25 | £15–25 |
| Form | Supplement (capsule/softgel) | Tablet |
The key takeaway: finasteride is significantly more effective, but saw palmetto has a much more favourable side effect profile. For men who’ve tried finasteride and can’t tolerate the side effects — or men who want a more natural approach — saw palmetto is a legitimate option.
Dosage: How Much Should You Take?
The clinical studies that showed positive results typically used 320mg per day, often split as 160mg twice daily.
Look for products standardised to contain 85–95% fatty acids and sterols — this is the active component. Many cheap supplements use low-quality extracts with inconsistent potency.
Don’t expect results in 4 weeks. Hair growth cycles are long. Give it at least 6 months before deciding whether it’s working.
The Best Saw Palmetto Supplements: UK Picks
NOW Foods Saw Palmetto Extract 160mg
★★★★★ 4.6/5One of the most trusted supplement brands globally. Standardised 160mg extract — take two for the 320mg clinical dose. Excellent quality control, great value. NOW Foods is the gold standard for no-frills, reliable supplementation.
✅ Pros
- Most trusted supplement brand globally
- Standardised extract — consistent potency
- Excellent value per dose
- Take 2 capsules for clinical 320mg dose
❌ Cons
- Requires 2 capsules per day for full dose
- Results take 6+ months to assess
1. Nutricost Saw Palmetto 500mg
High-dose, standardised extract. Good value for the quality.
Nutricost Saw Palmetto 500mg
★★★★☆ 4.3/5High-dose 500mg standardised extract — a single capsule gives you above the clinical dose. Good value for a quality standardised product.
✅ Pros
- High 500mg dose per capsule
- Standardised extract
- Good value for the quality
❌ Cons
- Less established brand than NOW or Solgar
- Higher dose may exceed what's needed
2. Solgar Saw Palmetto Berry Extract
Solgar is a well-established supplement brand with consistent quality control. Slightly pricier but reliable.
Solgar Saw Palmetto Berry Extract
★★★★★ 4.5/5Premium Solgar brand with excellent quality control — one of the most trusted names in professional supplements. Slightly pricier but worth it for brand reliability.
✅ Pros
- Solgar — premium trusted brand
- Consistent quality and potency
- Widely available in UK health stores
❌ Cons
- Pricier than budget alternatives
- Smaller capsule count per bottle
3. NOW Foods Saw Palmetto Extract 160mg
NOW Foods is one of the most trusted supplement brands globally. 160mg standardised extract — take two for the clinical dose.
NOW Foods Saw Palmetto Extract 160mg
★★★★★ 4.6/5The best value saw palmetto from the world's most trusted supplement brand. Standardised extract, excellent quality control, and very affordable. Take 2 per day for the 320mg clinical dose.
✅ Pros
- Most trusted supplement brand globally
- Standardised extract consistency
- Best value per dose
❌ Cons
- Need 2 capsules for clinical dose
- Results won't appear for 6+ months
4. Viviscal Man Hair Growth Supplements
Not purely saw palmetto, but includes it alongside biotin, zinc, and a proprietary marine complex. Designed specifically for hair loss and has its own clinical studies.
Viviscal Man Hair Growth Supplements
★★★★☆ 4.2/5A comprehensive hair growth supplement designed specifically for men — saw palmetto plus biotin, zinc, and a proprietary marine complex (AminoMar). Has its own clinical studies supporting hair thickness and density improvements.
✅ Pros
- Multi-ingredient approach
- Has clinical studies specific to this product
- Designed specifically for men's hair
❌ Cons
- Expensive for a supplement
- Marine complex may not suit everyone
- Contains fish — not suitable for vegans
Topical Saw Palmetto: Is It Worth It?
Some shampoos and serums contain saw palmetto extract, claiming to block DHT at the scalp level without systemic absorption.
The evidence here is even thinner — most topical products don’t have the concentration or formulation needed to penetrate deeply enough to affect follicle DHT. A few products show some benefit, but it’s not comparable to oral supplementation.
If you want topical DHT blocking, minoxidil remains the gold standard. Saw palmetto works better as an oral supplement.
Side Effects: Is It Safe?
Saw palmetto has an excellent safety profile. Reported side effects are rare and mild:
- Occasional mild stomach upset (take with food to avoid this)
- Rare headaches
- Very rare reports of reduced libido (far less common than with finasteride)
Importantly: saw palmetto does not appear to significantly affect PSA levels the way finasteride does, making it a safer option for older men being monitored for prostate issues (though always check with your doctor).
Not recommended for: Women who are pregnant or planning to become pregnant (anti-androgenic effects).
Should You Stack It With Other Treatments?
Many men use saw palmetto as part of a broader hair loss stack:
- Saw palmetto + minoxidil: A sensible combination. Saw palmetto addresses the hormonal side (DHT) while minoxidil directly stimulates follicle growth. Good evidence for this pairing.
- Saw palmetto + finasteride: Not usually recommended — stacking two DHT blockers with different strengths adds complexity without clear benefit.
- Saw palmetto + biotin/zinc: Complementary. Zinc also has mild 5-alpha reductase inhibiting properties. Check our guide to hair loss supplements here.
Bottom Line
Saw palmetto works — mildly. For men in the early stages of male pattern baldness, it can slow progression meaningfully. For men who can’t or won’t take finasteride, it’s the best natural alternative available.
But go in with realistic expectations. It’s not as powerful as finasteride, and it won’t reverse significant hair loss. Think of it as a speed reducer, not a reversal.
Recommendation: If you’re in early-stage thinning and want a conservative, prescription-free approach, start with 320mg/day of a standardised extract alongside minoxidil. Give it 6–9 months and assess.
If you’re losing ground faster than that, have the conversation with your GP about finasteride. Saw palmetto is good. Finasteride, for most men, is better.
