Saw Palmetto for Hair Growth: Does it Block DHT?

  • Medically reviewed by: Dr. Anil Simhadri
  • Written by: William Hartfield
  • Last updated: 25/01/2024

While prescription drugs like Propecia can be used to combat hair loss, they also have systemic side effects. For many people, the drawbacks outweigh the benefits.

But what about natural alternatives, like saw palmetto?

This post will cover all you need to know about saw palmetto and its use for treating hair loss. That includes:

  • What saw palmetto is and how it works.
  • The scientific evidence backing the use of saw palmetto for treating hair loss.
  • The correct dosage for saw palmetto.
  • How long until you can expect to see positive results.
  • The side effects to consider before beginning use.
  • How to use saw palmetto most effectively for hair growth.

Does Saw Palmetto Work?

This herbal supplement works in much the same way as the drug Propecia does, except that obviously it’s 100% natural so there are fewer side effects generally associated with its use.

The mechanism of action is inhibiting the enzyme 5-alpha-reductase. 5-alpha-reductase converts testosterone to DHT, which is generally accepted as the hormone responsible for male pattern baldness (MPB).

There is still debate about how effective saw palmetto is at preventing further hair loss and no conclusive studies have been undertaken. A small study did show positive results in six out of 10 subjects.

The caveat of this study is that the men were asked to rate how their hair loss had improved after a few months of taking the herb orally. No empirical checks were taken, such as a hair count.

Is There Any Medical Evidence?

It is more difficult to conduct reliable studies on the effectiveness of saw palmetto for MPB, one of the reasons is that no one in particular wants to fund the studies.

Merck (the company that makes Propecia) will happily fund a study on the drug, since they have a patent on the drug, so proving its effectiveness will certainly have a return on investment for them.

However, proving saw palmetto’s effectiveness won’t benefit any one company in particular.

That’s not to say that there aren’t available studies to consider, though.

University of Naples, Italy (2004)

A (brief) study was performed on this topic in 2004 by researchers at the University of Naples. Its goal was to determine whether Serona Repens (saw palmetto) had any effect on AGA hair loss.

To carry out this study, 34 men and 28 women were recruited and split into three groups:

  1. Used three products (shampoo, lotion, and supplements) enriched with saw palmetto;
  2. Used three products (shampoo, lotion, and supplements) without saw palmetto; and
  3. Used two products (shampoo and lotion) enriched with saw palmetto and a placebo supplement.

The study took place over a three-month period, and researchers tracked the results using trichograms, phototrichograms, and computerized analysis of the scalps.

As suspected, Group 2 (the placebo group) saw no significant results in either hair growth or sebum production.

Group 1 received the best results, with a 35% increase in hair number and mass, and a 67% decrease in sebum production.

Group 3 received relatively positive results, with a 20% increase in hair count and a 35% decrease in sebum production.

What do these results tell us?

Overall, they’re quite promising as it relates to saw palmetto in the treatment of AGA-related hair loss.

Rome, Italy (1998)

A more in-depth study was carried out in 1998, which sought to determine whether saw palmetto and gelatin-cystine could make a positive impact on hair growth.

This study included 48 volunteers (24 male and 24 female) who were instructed to apply the lotion (either active, or placebo) over a period of 50 weeks. Some participants (12 in total) were also given an oral supplement (which did not contain saw palmetto).

All 48 patients were diagnosed with AGA (Stages III to IV on the Norwood-Hamilton scale).

The study consisted of five groups, and here is the breakdown:

  1. Group 1: Active lotion A;
  2. Group 2: Inactive (placebo) lotion B;
  3. Group 3: Active diet supplement C;
  4. Group 4: Inactive (placebo) diet supplement D; and
  5. Group 5: Active lotion A and active diet supplement.

The lotion was applied twice daily, and the volunteers also received a mild shampoo which they were instructed to use throughout the study.

The mean percentage variation of hair number per squared centimeter of scalp was recorded throughout the study, and these were the results:

Saw palmetto hair growth study results

As to be expected, the placebo groups performed quite poorly, but the active groups (lotion, diet, and lotion + diet) all performed quite well. In fact, an increase of almost 40% was seen in the lotion + diet group, and the other two active groups saw increases of between 25% and 30%.

As saw palmetto wasn’t the only active component in this study, it’s hard to tell exactly how much of a role it played. However, the results are enlightening and can help to guide further research.

Rome, Italy (2012)

Finasteride is a popular drug treatment for AGA, as it works to inhibit 5AR and reduce DHT levels. It’s used by many men throughout the hair loss community, and its results can be quite amazing.

However, finasteride does have some side effects associated with its use.

This next study will be of interest to finasteride users and non-users alike, as it directly compares the efficacy of saw palmetto with finasteride.

The 2012 study consisted of 100 men total, all of which were diagnosed with AGA (mild to moderate). The participants were split into two groups.

The first group received 320mg of saw palmetto per day, while the second group was prescribed 1mg of finasteride per day. Both groups continued treatment for 24 months.

The participants were studied throughout the trial, and global photographs were taken at each stage and studied by three experts (two dermatologists and one junior dermatologist). These photographs were ranked using a 7-point scale.

These were the total scores, as tallied, by the end of the 24-week study:

A chart comparing the efficacy of saw palmetto and finasteride

Overall, results show that 38% of patients treated with saw palmetto saw hair growth while 68% of those treated with finasteride saw hair growth.

Does this mean that saw palmetto doesn’t work? Of course not!

While the results aren’t that impressive, they still do show that saw palmetto plays a role in hair growth. This is likely via the inhibition of 5-alpha-reductase, though further studies should be carried out.

And, while finasteride may prove to be more effective in this study, this may not be true if various concentrations of saw palmetto were tested or if different measurement techniques were utilized.

The main point I think from these studies is that the herb can be effective for hair growth, but one needs to take a double-pronged approach to solving the problem.

Saw Palmetto Dosage

Saw palmetto comes in many different forms, and considering the point above you may want to consider a few of the options:

  • powder capsules
  • dried whole berries
  • tablets
  • liquid extracts

In the first study mentioned the subjects took 200 milligrams twice daily, which is quite a large dosage. Something that I think it very important to remember when taking supplements is that everybody’s digestive system will absorb the herb differently.

For example, many of us have guts that are coated in undigested matter. This comes from a modern diet lacking in fiber, and the over-consumption of processed foods that are devoid of enzymes.

Dairy, grains (which irritate the lining of the GI tract), and red meats all contribute to a gut that will have difficulty processing foods and extracting active ingredients from any supplements you take.

How Long Will It Take to Work?

It’s important to remember that saw palmetto will not work for everyone. But even for those who it does work for, it won’t do so right away.

So, how long can you expect for this natural hair loss treatment to work?

Let’s take a look back at the studies we outlined above.

The first study was done over three months, the second study was done over 50 weeks, and the third study was done over 24 weeks.

While we can’t compare these studies directly, it’s safe to say that at least three months of use is necessary for results to be visible.

What should you look for exactly, though?

In the first study, they looked at hair number and mass, as well as sebum production to track efficacy.

That’s not to say that you’ll see significant hair growth in three months, or even in six months. But you’ll likely be able to tell in that amount of time if it’s the right treatment for you.

Saw Palmetto Side Effects

Although saw palmetto is generally considered to be safe, people have reported a few side effects of taking it. The most commonly heard one is that it can cause an upset stomach or even diarrhea.

This isn’t something you should worry about since it either happens or it doesn’t and can be avoided by taking it with food.

Saw palmetto does interact with your body on a hormonal level (albeit naturally, unlike finasteride) so you should pay attention to how your body feels in the following few days and weeks when you start. Always consult a doctor if you do decide to take it.

Interestingly, saw palmetto does not seem to cause the same erectile side effects as Propecia. This may be because saw palmetto helps benign prostatic hypertrophy (BPH) as well. Many hair loss sufferers suffer from BPH as well as androgenetic alopecia. Treating BPH can help improve erections. So in many ways saw palmetto is a superior option to Propecia.

Saw palmetto may reduce the effectiveness of oral contraceptives.

The tannins in the supplement can supposedly affect iron absorption, leading to iron (ferritin) deficiency, so you might consider taking an iron supplement as well. As an alternative to iron supplements, you can eat foods high in iron such as liver, sunflower seeds, nuts, beef, lamb, beans, whole grains, clams, and dark leafy greens to counteract the lack of absorption.

When using saw palmetto, make sure you eat plenty of iron-rich food due to the lowered absorption of iron that can be caused by the herb. The extra iron will also help with hair strength and thickness.

How to Use Saw Palmetto to Promote Hair Growth

There are two ways to utilize saw palmetto for hair growth – internally and externally. Let’s take a look at a few ways to do so.

Take a Saw Palmetto Supplement

With the popularity of saw palmetto on the rise, you may notice there are quite a few variants of saw palmetto available on the market.

These include dried berries (which are most often found in health food stores), powder capsules, tablets, and liquid extracts.

While there’s still much debate over how effective internal saw palmetto is when it comes to hair growth, as well as how much to take, you can take a supplement as part of your hair care routine.

There’s no ‘best’ type of supplement. As long as you take it consistently, that’s all that matters.

As such, you should choose the supplement type that appeals to you most. The capsules and tablets are the most convenient, as you can easily take those with a glass of water after a meal. However, the dried berries and liquid extracts can easily be added to teas, smoothies, and cereals.

Create Your Own Saw Palmetto Extract

Perhaps the most effective way to reap the benefits of saw palmetto is to apply it directly to the scalp. This was shown in the various studies above.

One way to do so is by making your own saw palmetto extract.

What You’ll Need:

  • Four dried saw palmetto berries
  • Two teaspoons of warm water


Place the dried berries in a bowl, and gently mash using a fork or the backside of a spoon.

Heat water in the microwave or using a kettle, and pour two teaspoons of the heated water over the berries.

Stir the mashed berries and water until they combine.

Once the mixture has cooled enough to touch, use your fingertips to scoop up the mixture and apply directly to your scalp.

Massage the extract into your scalp for two to three minutes.

Leave the extract on your scalp for at least 20 minutes, and then rinse away with lukewarm water.

Make a Saw Palmetto Conditioner

If you’re suffering from hair loss, it’s not uncommon to also suffer from dry, brittle hair. This makes it important to condition your hair regularly to prevent breakage and promote strong, healthy growth.

And while you can certainly get creative with your conditioner recipes, this recipe contains only two ingredients and takes just minutes to make.

What You’ll Need:

  • One tablespoon of aloe vera
  • Two – three tablespoons ground saw palmetto


If using dried saw palmetto berries, place the berries in a mortar and use a pestle to mash the berries until they’re finely ground.

If using tablets, crush the tablets with a mortar and pestle, or the backside of a spoon.

Place two to three tablespoons of ground saw palmetto into the container of your choose, and add in one tablespoon of aloe vera gel.

Mix the ingredients until well combined.

While in the shower and after shampooing, apply the mixture to your scalp and hair.

Massage into the scalp using your fingertips, and slowly disperse the mixture throughout your hair strands. Be careful not to tug on your hair to prevent breakage.

Leave in for five minutes, and then rinse in lukewarm water.

Are There Any Alternatives?

Are there complimentary supplements for saw palmetto? Yes, there are certainly other supplements that you should take as well, and other things you should be doing to help with hair loss.

In fact, that’s why this website is here. I teach you how I personally cured my hair loss using natural methods and how you can do the same.

As a side note, I wrote an in-depth article about the best natural DHT blocker here, although it’s probably not what you’re expecting, the overall approach is incredibly effective.

How Much Does It Cost?

You can find saw palmetto relatively cheaply on Amazon. I would recommend browsing the reviews and picking one that you like. I could give my own recommendation but it may change by the time you read this so it’s better to do have a look yourself.


Saw palmetto isn’t a hair loss breakthrough, but it may help to reduce DHT both orally and topically when used consistently. There are studies that show it is no more effective than a placebo, and studies that have promising results.

Whatever you decide to do, remember that supplements should only form a small part of the defense against pattern baldness.

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