Saw Palmetto vs Finasteride

June 3, 2025/Andrew Le

Two well-known hair loss treatments, saw palmetto and finasteride, both focus on lowering DHT, a hormone that shrinks hair follicles and causes hair loss.

Saw palmetto reduces DHT and blocks it from attaching to cells, while finasteride mainly stops DHT from being made. Because of this, they help slow hair loss and, in some cases, improve hair growth.

But which one works better, and what should you expect when using them? 

In this article, we’ll explain how each works, compare their results, guide you on how they’re used, and highlight possible side effects.

🔑 Key Takeaways

➤ Saw palmetto works by lowering DHT and also by keeping it from sticking to hair cells, which can help protect hair roots.

➤ Finasteride stops the body from making most of the DHT, cutting levels by about 70–90%, which makes it very strong at slowing hair loss.

➤ You need to take saw palmetto every day, usually 200–320 mg in a pill, and it may help more in mild cases but often takes longer to show results.

➤ Finasteride comes as a 1 mg tablet you take each day, and most people see a difference in hair thickness after about three months of use.

➤ Studies show saw palmetto can improve hair quality by around 60% and hair count by 27%, but finasteride often leads to more hair growth and stops hair loss in over 80% of users after two years.

➤ Finasteride can cause side effects like lower sex drive, mood changes, or rare breast issues, while saw palmetto usually only leads to mild headaches or stomach upset and rarely serious problems.

Mechanism of Action

Saw palmetto and finasteride both lower DHT to help with hair loss, but saw palmetto also blocks DHT from attaching to cells while finasteride only stops DHT from being made.

Saw Palmetto 

Saw palmetto, or Serenoa repens, has been studied for its possible effects on hair loss, particularly in men. 

According to a study, saw palmetto inhibits both type I and type II 5α-reductase enzymes in a noncompetitive way. This is important because these enzymes convert testosterone into dihydrotestosterone (DHT), a hormone that can shrink hair follicles and lead to hair loss. 

Another study also found that saw palmetto interfered with DHT by preventing it from binding to androgen receptors inside cells. They noted that saw palmetto had a stronger affinity for cytosolic receptors (those inside the cell fluid) compared to nuclear receptors (those inside the cell’s nucleus). 

In another report, rat prostate cells showed that saw palmetto competitively blocked the binding of [3H]methyltrienolone to androgen receptors. These findings suggest saw palmetto acts both by lowering DHT levels and by stopping DHT from attaching to its receptors. 

So why does blocking DHT matter so much? Well, DHT is one of the main drivers of hair follicle miniaturization, a key factor in hair thinning.

Finasteride 

Finasteride takes a different but related path. Finasteride is a competitive inhibitor of the type II and III 5α-reductase enzymes, meaning it blocks the enzyme’s action by directly competing with its usual target. This blockage stops the conversion of testosterone to DHT. Finasteride can reduce DHT levels in the prostate by about 90% and lower serum DHT levels by 70%. That’s a major drop, which explains why finasteride is so effective in treating hair loss. 

Interestingly, finasteride has minimal effect on the type I enzyme, which is found in the skin and scalp, yet it still significantly improves hair count over about 12 months of use.

Unlike saw palmetto, finasteride works only on enzyme activity and not on DHT receptor binding. But the result is a powerful reduction of DHT, which helps slow hair loss and improve hair density. If finasteride treatment stops, DHT levels bounce back to normal within 14 days, and prostate volume returns to baseline in about three months. This quick reversal highlights the need for ongoing treatment to maintain hair regrowth.

Dosage and Administration

Saw palmetto and finasteride are both taken daily for hair loss, but finasteride usually works faster and needs to be taken long-term to keep results.

Saw Palmetto 

Saw palmetto is usually taken by mouth as a supplement for hair loss. The most common daily dose is between 200 mg and 320 mg. You can take it with or without food, and it’s often taken once a day. 

Some products also come as lotions or topical treatments, but it’s hard to tell if the lotion works because it usually contains other ingredients. When taken as a capsule or tablet, consistency is key—you need to take it every day to possibly see benefits over time. 

But keep in mind, even with regular use, saw palmetto tends to be less effective compared to standard hair loss medications. 

Finasteride 

Finasteride is usually taken as a 1 mg tablet once a day. You can take it with or without food, but it’s best to take it at the same time every day. To see noticeable results, daily use for at least three months is needed, and continued use is important because stopping treatment will usually cause hair loss to return within a year. 

Finasteride can also come as a topical solution, though it’s not widely approved yet. The pill should be swallowed whole with water—don’t break or crush it. 

Efficacy

Saw palmetto can modestly improve hair loss, especially in mild cases, while finasteride has been shown to work much better in stopping hair loss and boosting hair growth over time.

Saw Palmetto 

According to a metanalysis study, several clinical studies show promising but limited results for saw palmetto in treating hair loss. 

Five randomized clinical trials and two cohort studies showed that saw palmetto supplements, taken either orally or topically in doses of 100–320 mg, led to a 60% improvement in overall hair quality and a 27% increase in total hair count. Even more impressive, 83.3% of patients showed increased hair density, while 52% had their hair loss progression stabilized. These numbers suggest that saw palmetto may help improve hair appearance and slow down hair loss. 

However, the researchers emphasized that more large-scale studies are needed to fully understand how well saw palmetto works, especially when used alone. So, while saw palmetto seems helpful for some, we still don’t know if it’s the best solution for everyone.

In a 2012 study, researchers followed 100 men with mild-to-moderate androgenetic alopecia over two years. One group took 320 mg of saw palmetto daily, while another group took 1 mg of finasteride. By the end, 38% of men taking saw palmetto had hair improvement. This suggests that saw palmetto had a real but modest effect, especially in milder cases. Interestingly, the study also noted that the more severe the hair loss, the less saw palmetto helped, making it less effective in advanced stages. 

This raises an important question: Should saw palmetto only be recommended early on?

In a more recent 2023 study, the researchers tested VISPO™, a standardized saw palmetto oil, in 80 men and women with mild-to-moderate androgenetic alopecia over 16 weeks. Participants either took 400 mg oral capsules or used a topical product with 20% VISPO. Both forms worked well: oral VISPO reduced hair fall by 29%, while topical reduced it by 22.2%. Hair density increased by 5.2% with oral and 7.6% with topical treatment. Plus, oral VISPO lowered DHT levels in the blood significantly. Importantly, no major side effects were reported. This study adds strong evidence that saw palmetto, especially in well-prepared products, can meaningfully reduce hair loss and improve hair growth.

Finasteride 

According to a study, finasteride, a 5-alpha-reductase inhibitor, stops testosterone from turning into DHT, the hormone that causes male pattern baldness. Phase III studies in 1,879 men showed that taking 1 mg/day of finasteride led to better hair growth and stopped further hair loss in many men. After one year, global photos showed hair improvement in 48% of men, and by two years, 66% showed improvement. 

In comparison, only 7% of men taking a placebo improved at both time points. Even more, hair counts showed that after two years, 83% of finasteride users had no further hair loss, while only 28% of placebo users kept their baseline hair.

Another study reported results from two one-year trials with 1,553 men aged 18–41 who took 1 mg/day of finasteride or placebo. Among 1,215 men who continued into a second year, scalp hair counts improved significantly. In a 1-inch circular area of balding scalp, finasteride users gained 107 hairs after one year and 138 hairs after two years, while the placebo group continued to lose hair. Patients said that finasteride slowed hair loss, boosted hair growth, and improved hair appearance. Investigators and expert panels agreed, based on photos. The side effects were minimal.

Finasteride slowed hair loss and increased hair growth over two years, as confirmed by different assessment methods. 

Side Effects 

Finasteride can cause sexual problems, mood changes, breast changes, and allergic reactions, while saw palmetto usually has mild side effects like headache or nausea, but may rarely cause serious issues.

Finasteride 

Finasteride can cause a variety of side effects. These include:

  • Problems getting an erection and less interest in sex (happens in more than 1 in 100 people).
  • Problems with ejaculating, such as little or no semen.
  • Low mood or depression, and if taken for hair loss, people are advised to stop it right away if this occurs.
  • Lumps, pain, or swelling in the chest area, or nipple discharge — which may be signs of a serious condition like breast cancer.
  • Serious allergic reactions like swelling of lips, mouth, throat, or tongue; difficulty breathing; tight throat; pale or bluish skin; confusion, dizziness, fainting, or children becoming limp or floppy.
  • Breast changes such as clear or bloody discharge, dimpling of the skin, inverted nipple, breast lumps, redness or swelling, or sores on the skin of the breast that do not heal.
  • Other possible side effects include chills, cold sweats, dizziness, lightheadedness when standing up, bloating or swelling in the face, arms, hands, lower legs, or feet, rapid weight gain, tingling in the hands or feet, back pain, diarrhea, headache, stomach pain, runny or stuffy nose, sneezing, sleepiness, and testicular pain.

These side effects can sometimes continue even after stopping the medication, which is an important consideration.

Saw Palmetto 

Saw palmetto is generally considered safe when used as directed, but some mild side effects have been reported. These include:

  • Headache
  • Nausea
  • Diarrhea
  • Dizziness

In rare cases, saw palmetto has been linked to:

  • Significant bleeding during surgery (so it’s advised to stop at least two weeks before surgery)
  • Two reports of liver damage
  • One report of pancreas damage

However, it’s not clear whether saw palmetto directly caused these rare problems.

Wrap Up

Saw palmetto may work better in mild cases, especially if taken early. Finasteride, on the other hand, gives stronger and more consistent results, especially for long-term use.

However, not all treatments suit everyone. Some people may prefer saw palmetto because the side effects are usually mild. Others may go with finasteride for its proven power, despite the possible risks. It all depends on your needs, how severe the hair loss is, and how your body reacts.

So, what matters most—a natural option or stronger results? The answer depends on what you’re comfortable with and what your hair really needs.

Frequently Asked Questions

Can I use saw palmetto and finasteride together?

Yes, you can. Some people combine them, but always check with a doctor first to make sure it’s right for you.

Can women use finasteride or saw palmetto?

Finasteride is generally not used for women, especially those who are or may become pregnant. Saw palmetto is sometimes used by women, but talk to a doctor first.

Do I need a prescription for finasteride?

Yes, finasteride is a prescription medicine. You’ll need to talk to a doctor before starting it.

Is saw palmetto FDA-approved for hair loss?

No, saw palmetto is not FDA-approved for hair loss. It’s a supplement, so it’s sold without a prescription.

Sources

  • Di Silverio, F., Monti, S., Sciarra, A., Varasano, P. A., Martini, C., Lanzara, S., D’Eramo, G., Di Nicola, S., & Toscano, V. (1998). Effects of long-term treatment with Serenoa repens (Permixon) on the concentrations and regional distribution of androgens and epidermal growth factor in benign prostatic hyperplasia. Prostate, 37(2), 77–83. https://doi.org/10.1002/(sici)1097-0045(19981001)37:2
  • Sultan, C., Terraza, A., Devillier, C., Carilla, E., Briley, M., Loire, C., & Descomps, B. (1984). Inhibition of androgen metabolism and binding by a liposterolic extract of Serenoa repens B in human foreskin fibroblasts. Journal of Steroid Biochemistry, 20(1), 515–519. https://doi.org/10.1016/0022-4731(84)90264-4.
  • Carilla, E., Briley, M., Fauran, F., Sultan, C., & Duvilliers, C. (1984). Binding of Permixon, a new treatment for prostatic benign hyperplasia, to the cytosolic androgen receptor in the rat prostate. Journal of Steroid Biochemistry, 20(1), 521–523. https://doi.org/10.1016/0022-4731(84)90265-6.
  • Evron, E., Juhasz, M., Babadjouni, A., & Atanaskova Mesinkovska, N. (2020). Natural hair supplement: Friend or foe? Saw palmetto, a systematic review in alopecia. Skin Appendage Disorders, 6(6), 329–337. https://doi.org/10.1159/000509905.
  • Rossi, A., Mari, E., Scarno, M., Garelli, V., Maxia, C., Scali, E., Iorio, A., & Carlesimo, M. (2012). Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: A two-year study. International Journal of Immunopathology and Pharmacology, 25(4), 1167–1173. https://doi.org/10.1177/039463201202500435.
  • Sudeep, H. V., Rashmi, S., Jestin, T. V., & Richards, A. (2023). Oral and topical administration of a standardized saw palmetto oil reduces hair fall and improves hair growth in androgenetic alopecia subjects: A 16-week randomized, placebo-controlled study. Clinical, Cosmetic and Investigational Dermatology, 16, 3251–3266. https://doi.org/10.2147/CCID.S435795.
  • Kaufman, K. D., Olsen, E. A., Whiting, D., Savin, R., DeVillez, R., Bergfeld, W., Price, V. H., Van Neste, D., Roberts, J. L., Hordinsky, M., Shapiro, J., Binkowitz, B., & Gormley, G. J. (1998). Finasteride in the treatment of men with androgenetic alopecia. Journal of the American Academy of Dermatology, 39(4 Pt 1), 578–589. https://doi.org/10.1016/s0190-9622(98)70007-6.
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