Penis Extender Results from Clinical Studies

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Updated on March 28, 2020

Here are the before and after photos from men who used a penis extender.

Before and After Photos #1

Extender Used: PhalloGauge Extender

Price: $115

Here are the before and after photos for men that used the PhalloGauge Extender.

image of the best penis extender

Male Lab Subject #3 Verdict: Significant length gain.

Dr. Edward Matsumoto's Review: This is currently 2019's best penis extender which is built by actual doctors.

PhalloGauge Before and After Result

phallogauge before and after picture result 2

Male Lab Subject #9 Verdict: Significant length and girth gain.

phallogauge before and after picture result

Male Lab Subject #3 Verdict: Significant length gain.


15 Male Subjects Gained an Average of 30% in Length Over 3 Months.
size results graph of phallogauge extender male subjects
15 Male subjects that used the PhalloGauge Extender gained an average of 30% in size.

(Data from PhalloGauge Medical Lab Fall 2018 study)

One of our latest participants aged 36, who ordered in October last year. After noticing a gradual reduction of his natural size due to his age, he thought there was nothing he could do.

He first tried pumps, then pills, and realised that they could only give temporary results. Some of them did nothing at all. He spoke to his Doctor about his size shrinkage issue who then recommend he try a penis extender. He reported "solid results" within the first 14 days and says his erection quality is far superior than it has been in recent years. 36 weeks of solid use later, these are his positive results!

Before and After Photos #2

Extender Used: SizeDoctor Extender

Price: $179

Here are the before and after photos for men that used the SizeDoctor Extender.

sizedoctor Penis Extender

Dr. Edward Matsumoto's Review: The best dual-rod extender. Made by actual doctors.

SizeDoctor Before and After Result

sizedoctor before and after picture result

Male Lab Subject #31 Verdict: Large length gain.


15 Male Subjects Gained 25% in Length Over 3 Months.

size results graph of sizedoctor extender male subjects
15 Male subjects that used the SizeDoctor Extender gained an average of 25% in size.

(Data from PG Medical Lab Fall 2018 study)

sizedoctor extender

Before and After Photos #3

Extender Used: SizeGenetics Extender

Price: $200

Here are the before and after photos for men that used the SizeGenetics Extender.

parts of the SizeGenetics Penis Extender

SizeGenetics Before and After Result

sizegenetics before and after picture result

Male Subject #8 Verdict: Small length gain.

15 Male Subjects Gained Only 4% in Length Over 3 Months.

size results graph of Sizegenetics extender male subjects
15 Male subjects that used the SizeGenetics Extender gained an average of 4% in size.

(Data from PhalloGauge Medical Lab Fall 2018 study)

PhalloSan Before and After Picture

Price: $349

Here are the before and after photos for men that used the PhalloSan Forte.

PhalloSan Extender
phallsoan before and after picture

Male Subject #12 Verdict: No significant length gain.

Quick Extender Pro Before and After Picture

Price: $349

Here are the before and after photos for men that used the Quick Extender Pro.

quick extender pro before and after picture

Male Subject #18 Verdict: No significant length gain.

Jes Extender Before and After Picture

Price: $349

Here are the before and after photos for men that used the Jes Extender.

jes extender before and after picture

Male Subject #14 Verdict: No significant length gain.

More Before and After Photos for 3 Male U.S. Subjects

Clearly, penis extenders are effective.

a before and after photo of penis extender results - example 1

Click here to see the uncensored photo above.

a before and after photo of penis extender results - example 1

Click here to see the uncensored photo above.

a before and after photo of penis extender results - example 1

Click here to see the uncensored photo above.

Another way at looking at this penis extender data.

It may be hard to visualize the actual results from just the photos above because both the before and after penis extender results are zoomed in and focusing on the penis and doesn't show the to-scale visual difference.

To solve this problem, we created a proportional bar graph that shows you the penis extender results for these male subjects above.

Resulting Data:

bar graph showing the before and after penis extender results

The penis extender results are:

  • 26% gain for the Los Angeles subject.

  • 48% gain for the New York subject.

  • 45% gain for the Orlando subject.

These percentage penis extender results illustrate an extremely important concept:

You can gain more size if you're smaller rather than starting out large.

This means that the guys who are 5 inches or below have most to gain!

Look at the data.

The subject from LA who started out at 6.9" and ended up at 8,7", he only got a 26% gain!

Don't get me wrong - while that is still a lot, it still doesn't compare to the other subjects from NY and Orlando who got a 48% and 45% gain, respectively!

This conecpt is also known as "Newbie Gains".

That is, a beginner who never trained before, will experience the most size gain in a given period of time, compared to the veteran, who has been training for 10 years.

This is phenomenon that we already see in the "normal" body modification / health industry, so it's not surprising that we see working with penis extenders.

How these numbers work in your favor:

The best thing about these pictures?

Every single one of these men gained size.

Again that's an overlooked fact, that once you understand completely changes your persepective on penis extender effectiveness.

Do the regimen, and you will gain some size.

What does this mean?

It means if you do a penis extender regimen and stick with it, you won't not gain size.

That means you will gain some size.

See, the penis extender result data shows us that each of the three men gained size.

Sure, we can debate and conduct more studies on why men gain more size than others, but the simple fact is all of them gained size.

Now, there's a clear path to permanent size, it takes some committment.

Here are the results from recent studies done on popular penis extenders on the market:

How we filtered these results:

The data points that were thrown out:

  • Any data that showed a length decrease of over 1 inches.

  • Any data that showed a girth decrease of over 1 inches.

  • Any data that showed a length increase of over 4 inches, as this most likely an untrue outlier.

  • Any data that showed a girth increase of over 3 inches, as this most likely an untrue outlier.

Why throw this data out?

The simple fact is that these sort of gains from natural penis enlargement are completely impossible.

Since we know that this is a fact, we can be confident not to trust this data.

Think of it this way:

If these results were real - others would also experience them and penis enlargement would be completely mainstream.

However it's not - they are outliers.

The generally accepted penis extender results for length are .7 inches in 16 weeks.

That's why we're presenting these results to prove that claim.

Typical girth and length gains experienced by the general population.

Here is the first interesting graph from Thunder's.

girth vs length gains scatter plot

It shows that there are many men that experience a non-zero size gain when engaging in penis enlargement.

Why is this so powerful?

Many men overlook this fact and dismiss it as ordinary.

However, those that do are missing out a very powerful truth.

That truth is:

If you even try to do some penis exercises - you will gain at least a small result.

Here's another way of looking at the resulting data above:

What if it were the case that penis enlargement, was in fact, impossible?

Then we would expect men to see 0 girth gains and 0 length gains.

That means the graph above would instead look like this:

It would have all the points overlapped at the 0, 0 point!

In other words, you would have all the thousands of points centered on the 0, 0 mark on the plot, and it wouuld be a really dark blue there!

That just isn't so with the data pressented above!

Yes, it's true that some guys have gained more than others - there's no disputing that.

But the fact that the vast majority gaiend some size is an accomplishment in of itself.

Typical Penis Extender Results by Thunder's Men

Length Results (BPEL)

Here's the Thunder's plot for BPEL length gains that men experienced after using a penis extender.

(If you don't know how to measure BPEL, go here.)

plot of length gain results (BPEL) after penis extender training

This is another interesting plot to analyze.

Let's first take the "zero-case", that is, if literally none of the men were to experience any gains at all.

What would the graph look like?

It would look like a completely flat horizontal line of data points, all algined with the y-axis of BFEL Gains = 0.

It would basically be saying that, "No matter what your starting size, you will have gained zero length or girth gains."

That is simply not the case here.

Looking at the plot, it would be safe to say that a vast majority of the men experienced 0.5 inches of length gain, or more.

One crucial thing to understand about these penis extender results:

Granted, these numbers were reported at some point in time after using a penis extender.

However, the actual time after each report varied from man to man.

In other words, some guys may have reported their increase one month after doing exercises, and some may have reported a few months to a year after using a penis extender.

That would explain the great variance in the data.

So while this data is not the best to learn how much you can gain in x amount of time, it is still reassuring that you will gain penis size if you just try.

That's the point is: There is literally nothing stopping you from accomplishing it (given sufficient motivation to actually want to succeed)!

Typical Penis Girth Gains Experienced by Thunder's Men

Girth Results

Alright, here is the last data plot from Thunder's:

plot of girth gain result after penis enlargement training

Ah, the final crucial measurement when it comes to penis size: girth.

This data wouldn't be complete if it wasn't for this last girth plot.

So let's analyze the penis extender results.

It seems same trend is occuring.

Again, taking the "zero-case" (also known as the "null hypothesis") - if penis enlargement was impossible, then there would be zero gains experineced by the vast majority of the men.

This would be represented as a flat, horizontal line of points aligned with the 0 on the y-axis.

This is simply not the case, again!

Again, just like the length gains, the girth results are varied, but are non-zero.

It seems that at least 75% of the points showed a girth gain of 0.25 inches or greater.

When it comes to girth, seemingly small gains are actually a lot.

Any small girth gains are actually a lot when it comes to sex.

That's because girth represents how wide you can stretch your partner open.

Girth allows you to press on her vaginal walls more and stimulate her harder without trying as hard.

Quite frankly, a girth gain result of 0.25 inches is actually really good and although it seems small, she will definitely notice the difference.

Just ask her.

Again, this is another fantastic, reassuring result for those that are still skeptical about penis extender efficacy.

Some critical points to consider about these penis extender results:

This clinical data does not tell what natural penis enlargememt techniques were used.

While we can be fairly confident that the appropriate length exercises and girth exercises were used, the exact routines weren't disclosed.

Length gains results are typically achieved with both penis extenders and manual stretching.

Girth gains results are typically achieved with jelqing and penis pumps.

This data was not provided in a secure environment.

Again, this is just the penis extender result data that was harvested from Thunder's website.

This includes their articles and forum posts.

The results were provided by random men on the internet, so that makes the data less consistent.

However, the best way to combat the lack of credibility is to have a large sample size, which is exactly what Thunder's has provided here.

This data does not show the time spans used for each male subject.

Most likely, a guy who experienced an inch gain, was doing penis training longer than a guy who was using a penis extender for a couple of weeks.

This is just common sense.

However, Thunder's did not explicitly say how long each subject conducted their penis enlargement routines for.

While it will be interesting to know how long each guy took, such an experiment will probably be reserved for a newer study in the future.

Studies Done on Penis Extender Efficacy Around the World

Here are the widely accepted penis extender results:

You can expect to gain .7 inches in length if you use the penis extender for at least 6 hours a day for 24 weeks (6 months).

Another important point is that it doesn't matter if you use a rod-based extender like the SizeGenetics or a belt-based extender like the PhalloGauge Extender or the PhalloSan.

We know this is true because there were two clinical studies, one for the rod-based extender and one for the belt-like extender and both penis extenders yielded the same result: .7 inches in 6 months

Ok. Now that we have the penis extender results agreed upon by the scientific community, let's take a look at real photos of what this actually looks like.

1. The Clinical Review published by 5 doctors from Moscow, Russia

This review used 50 men as subjects and were instructed to wear a penis extender for 4 hours a day.

The Results:

  • The average erect penis length gain was .7 inches of the course of 16 weeks!

  • The results were officially considered statistically significant.

  • The highest gain a man experienced in this review was 2.55 inches!

The Power of Newbie Gains

If you take the time to follow that link to the review above, you'll learn about something called newbie gains.

In a nutshell, newbie gains are the accelerated growth you experience when you start using a penis extender for the first time.

2. The Clinical Review done at Jiaotong University and the Renji Hospital in Shanghai, China

Now, let's talk about the clinical study done in Shanghai, China.

Jiaotong University School of Medicine Logo

The Key Takeaways

  • The average flaccid penis length gain was a whopping .84 inches!

  • The average erect penis length gain was an even more impressive 1.2 inches!

  • This review also reported that the all men safely used the device, and had no problems when using it.

I'd like to point out the doctor's conclusion on the safety of the penis extender device, because not only does this make it practical for every man to gain size, but that means the barrier to entry is practically non-existent.

Contrast this to something like penis enlargement surgery, which has an abysmal succses and mortality rate, and you've got a real game changer, not only for you, but for all men.

3. The Extender Study done at University of Turin, Italy

Need more proof that penis extenders work?

Here's another study that was done by the University of Turin in Italy.

The results for this study were so insightful that it made it into the British Journal of Urology International publication.

BJUI cover logo

The Key Takeaways

  • The median length gain of the men who participated in the study was .52 inches.

  • This review was interesting because they gave a questionaire to each of the men that completed the study. The postive results are summarized below.

The post-study questionaire:

The questionaire consisted of 5 questions and each were answered with a scale rating of 0-3 or 0-4, depending on the question, where 0 was the worst response, and 3 or 4 being the most postive response.

Question 1 was about penile curvature correction which scored a 1.6 on an average of scale of 0-4.

Question 2 was about satisifaction with penis flaccid length which scored an average of 1.96 "acceptable improvement" on a scale of 0-3.

Question 3 was about satisifaction with penis erect length which scored an average of 1.96 "acceptable improvement" on a scale of 0-3.

Question 4 was about satisifaction with sex life which scored a 1.6 "acceptable improvement" on an average of scale of 0-3.

Question 5 was about satisifaction with the overall result achieved which scored an average of 2 "acceptable" on a scale of 0-4.

About this penis extender review.

This penis extender study was conducted by the Jiaotong University in partner with the Renji Hospital in Shanghai, China.

A complete report of this study can be found here.

Renji Hospital Logo - Shanghai, China Jiaotong University, Shanghai, China - Logo

The experimental setup

30 subjects were used as the data for this review. 30 subjects is a good number because most United States FDA efficacy trials for new medical devices on the market require about 20 subjects. And getting FDA approval is much harder.

Therefore, the number of 30 subjects is a great number for the purposes of proving penis extender effectiveness.

The subjects were also between the ages of 16 and 70 years of age.

The subjects were instructed to wear the penis extender for 9 hours a day.

Subjects were checked and measured once a week. The measurements were done on the dorsal side (top) of the penis shaft.

The Numerical Results of the Penis Extender Study

Ok, now that we know how this review was done, let's take a look at some of the resulting numbers.

Below is a table documenting the size gains for the subjects.

Let's first take a look at the column labeled "Length of flaccid" because we know that penis extenders primarily target length.

The average flaccid length gain after three months was 2.1cm (9.2 - 7.1) - that's a gain of .84 inches!.

Now let's take a look at the column labeled "Length of erect".

The average erect length gain was a 3cm (12.3 - 9.3) - that's a whopping gain of 1.2 inches!.

The Conclusive Results of the Shanghai Review.

For the purposes of this review, they set the following rule:

The penis length of the subject must increase past 0.4 inches (1cm) no later than 3 months.

They found that all subjects succesfully met this criteria after the study was finished, and the success rate was thus, 100%!

This is great news for the general population because the data and statistics prove that if you closely follow a penis extender regimen, you too will experience the same results - there are no outliers.

Alternative Methods

Next are some reports on the safety of penis extender devices. Their findings were quite positive.

This is very good because it is in stark contrast to penis enlargement surgery which has a poor success rate ~50%, and a very real, mortality rate that can't be ignored.

While penis extenders are less risky, they do take longer to achieve results, but if you combine the fact that they are extremely effective (100% success rate as mentioned earlier, for this study), and completely safe (no risk of death or injury), these devices are massively useful tools that will set you up for a lifetime of penis size satisfaction.

Here, we're going to answer the question: "What is penis traction?" and "Can it safely increase my penis size?"

You're in the right place because we are going to report the findings from recent scientific studies.

In this report, you're going to learn everything you need to know about penile traction:

  • How size is added at the cellular level.

  • What penis traction is.

  • How the penis extender applies penis traction principles.

  • Conclusions from medical studies on the effects of penis traction.

Let's get started.

What is Penis Traction?

Clinical penis extenders work by utilizing the "traction principle", also known as "penis traction" or "penile traction therapy (PTT)".

The traction principle, put simply, involves keeping a body part in a "stretched" position for long periods of time.

The result?

The human body has a fascinating ability to adapt to the tension and experiences Cell Hyperplasia: A growth in body tissue size.

Cell hyperplasia means that the body cells (for us, in the penis) split and double, thus increasing the total number of body cells.

This is effect is biological in nature and is theorized to contribute to the survival of the body tissue.

Diagram showing how cells duplicate in response to using a penis extender.
The traction force causes penis cells to divide - resulting in a net increase in penis tissue mass = physical size increase.

The end result is indisputable, permanent size gains simply due to increased net penis tissue mass.

Tribal human with elongated earlobes due to cell hyperplasia.
Similar to earlobe elongation, the same effect happens to the penis during penis traction.

How does it work?

The concept is to gradually stretch the penis such that it becomes bigger in size over time.

Benefits of Penis Traction:

The research results reported by the British Journal Urology International (BJUI) was:

.7 inch length gain in 16 weeks.

That's quite a remarkable result given that even the thought of trying to increase your penis size was thought to be a waste of time.

I don't know about you, but if I found out that I could permanently increase my penis size by nearly an inch with practically no safety risk, I would go for it 100%.

But don't take our word for it.

Penis extender products apply the science of penis traction for growth.

Here are the clinical studies done that contain all the data that back up these results.

In a clinical study published in 2011, conducted by two doctors: Nikoobakht and Shahnazari, they found the following:

  • The average flaccid penile length increased from 8.8 cm to 10.1 cm in the first month of the study.

  • The average flaccid penile length increased from 8.8 cm to 10.5 cm in the third month of the study.

  • The average erect penile length increased from 11.5 cm to 12.4 cm in the third month of the study.

  • The average erect penile length increased from 11.5 cm to 13.2 cm in the third month of the study.

They concluded that these size increases were considered "statistically significant".

In a 2016 study conducted by Department of Urology, Section of Andrology of the Akdeniz University School of Medicine in Antalya, Turkey, in conjunction with the Department of Urology, Başkent University Alanya Research

Hospital, they concluded that penis traction was considered an effective, minimally invasive treatment if the patient was willing to commit to the "relatively long treatment period".

This makes sense given that the recommended penis extender usage is prescribed at 4-6 hours a day for 12 weeks (about 3 months).

Lastly, in a 2013 study conducted by Dr. Eric Chung from the Department of Urology of Princess Alexandra Hospital in Brisbane, QLD, Australia, found that penis traction therapy provided minor length gains, but more

importantly, helped to correct the curvature found in men suffering from Peyronie's Disease.

Exclusive Bonus: Download the UK and Spain penis extender clinical studies that each report how much length each man gained.

Conclusions from the Studies Done From Penile Traction Devices:

Out of numerous studies presented to find out if penis extenders do really work, we can safely conclude that they do work as long as the user carefully follows the manufacturer's instructions for the penis extender device being used.

Penis extenders are the perfect tools that will guarantee your penis lengthening success.

They aid you in your penis training by allowing you to stretch for longer without affecting your day-to-day lifestyle.

They have been clinically proven to work and because all men are the same, there's no reason why it shouldn't work for you as well.

We covered the different types of extender systems (pulling and rod-based) how to use them.

We also covered the common things to expect when wearing it.

By applying these points covered in these studies, you'll practically be on your way to getting a larger penis in no time, just as tens of thousands of guys have done before you.

To check out the PhalloGauge Penis Extender, which was designed for your user experience (results, comfort, stealth), you can learn more about it here.

They reported for the first time that ptt increased the size of the erect penis by 0.5 to 1.0 cm, with the hinge effect improving in four out of four men with advanced narrowing or indentation.

No patient reported significant adverse events such as changes in the feeling of the penis, deterioration in erectile function or skin injuries.

Another important study on the use of PTT in men with Parkinson's was published a year later.

More importantly, the authors reported that even 6 months after ptt, there was no further change in penis curvature or length.

The results of this study suggest that while using a penis extender resulted in minimal improvement in penile curvature, there was adequate patient satisfaction, most likely due to the increased penis length.

Recently, in a non-randomized prospective controlled trial, the researchers specifically evaluated the effectiveness of a penile traction device for treating men in the acute phase of Parkinson's disease.

In this study, 55 patients underwent PTT for 6 months and were compared to 41 patients with acute PD phase who did not receive active therapy.

A total of 40 men who underwent PD surgery (12 men with a graft and 28 men with only a penile splicing) were randomized to penile traction compared to the observation.

The use of a penis extension device was associated with an increased penis length in the range of 1 to 3 cm and appeared to be proportional to the number of hours per month that the patient wore the traction device.

In addition, continued treatment with PTD for 4 months increased the penis length from 1 to 4 cm.

The use of the device was well tolerated and only three patients had to reduce the number of hours of use of the traction device due to mild penis pain.

The elongated penis length and the upright penile curvature were measured using penile ultrasound.

Men who used the device for more than 3 hours a day gained 0.6 cm of stretched penis compared to 0.07 cm if they were used less than 3 hours a day, while men who did not use the device averaged 0,74 cm of stretched penis lost.

In summary, this study showed that a better improvement in curvature and an increase in the elongated penis length was observed in the combination group.

In addition, a multivariate analysis showed that the length improvement was related to the length of time the towing vehicle was used (20).

It seems logical that penile traction therapy (ptt) should offer a similarly effective treatment solution for pd.

The idea of ​​a non-surgical method that creates progressive mechanical traction of the deformed penis by lengthening and correcting abnormal penile curvature is very attractive.

Much attention has been paid to the use of a penis traction device in recent years.Many websites and advertisements proclaim that these non-invasive methods increase penis size and correct penile curvature.

Ptt, which creates gradual mechanical traction of the penis, has been described as an efficient, non-surgical treatment option for men with pd.

The use of PTT has been suggested to lengthen the penis in both an upright and a flaccid form (6,7).

In this article, we would like to review the current literature on the use of PTT in men with Parkinson's and beyond for use in certain patient subgroups, including men with shortened penis, before placing the penile prosthesis.

Studies have reported that penis extenders improve erectile function without side effects in 9 out of 13 users after 9 months of use.

To further explain this, the penis stretcher acts as a training device that makes the tissue of the penis more sensitive to stimulation and more adaptable to blood flow during the erection.

Often, using a traction device turns out to be much more effective for many men than pills, supplements, or even surgical treatments.

For this reason, most men who use penis extenders report harder erections, increased endurance and better sexual performance.

SizeGenetics Results

Sizegenetics has a traction of 2,800 g (98 oz), making it one of the strongest penis straps on the market, which is second only to Quick Extender Pro.

The traction provided by the mechanism offers first-class comfort because it is more comfortable than most other devices along the penis shaft.

In addition, the 3M comfort plaster holds the device in a way that is superior to most other penis extenders.

Since the device ensures a safe, simple and convenient enlargement of the penis, the SizeGenetics penis extender is one of the best options to choose from.

Alternative Methods

One method to make the penis thicker is to take fat from a fleshy part of the body and inject it into the penis shaft.

However, the results can be disappointing as part of the injected fat can be absorbed by the body.

Another technique to increase the width is to graft tissue onto the penis shaft.

None of these procedures have been shown to be safe or effective and may even affect the effectiveness and your ability to achieve an erection.

The most common surgical procedure to lengthen the penis is to cut the suspensory ligament that attaches the penis to the pubic bone and move the skin from the abdomen to the penile shaft.

When this ligament is cut, the penis appears longer because more of it hangs down.

Cutting the suspensory band can, however, cause an erect penis to become unstable.

Penis enlargement procedures are used to increase the size of the cavernous cylinders of the penis or to stimulate blood flow to increase hardness.

Penis enlargement or male enhancement is any technique aimed at increasing the size of a human penis.


The biggest conclusion to gain from these results is:

Do something, and you'll gain something.

The converse is also true:

Do nothing, and you'll stay the same.

Based on the results presented, most guys were able to achieve a .7 inch length gain and a .25 inch girth gain.

So what do you think about this data?

If you're looking for a device that will do the hours of stretching exercises for you, you may be interested in our extender that thousands of men already use.

FTC Disclosure: Results discussed on this website are understood to be "generally expected results" in compliance with all FTC requirements. Any extraordinary results experienced by any individual is specified explicitly. Results may vary from individual to individual. Customer testimonials are remunerated and do not claim specific results. Any results mentioned are assumed to be based on average customer results and are not based on extraordinary claims. If you should find any advertisements or claims to be unrealistic or extreme, please contact us and we will immediately review the content. Statements on this website have not been evaluated by the Food and Drug Administration. Discusssed products are not intended to diagnose, treat, cure or prevent any disease.

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