Aswagandha in male fertility, testosterone, stress, exercise performance & recovery

In the previous article, we looked at the benefits of Aswagandha (Withania Somnifera) for mental health, insomnia and cognitive performance. This time we will look at some of the interesting research on men’s health, including fertility, testosterone levels, exercise performance and post-workout recovery. In this part, I want to reiterate that findings in this article are based on a very limited amount of research, and so it is too early to say if these finds can easily be replicated and whether they are really true or just based on coincidence or random chance. As always, more research in herbal medicines is needed, but for now, this is what we go 😊


In this article I will be referring to Aswagandha as "WS"


Aswagandha & Male Fertility

To this date, a few studies have investigated the effects of WS on male fertility. Here is a quick review and findings from all of them:

  • In a study from India on 46 oligospermic (low sperm count) men divided randomly into two groups (WS group & placebo group), those taking WS extract had a dramatic improvement in sperm count, sperm motility and semen volume. The blood levels of an important sex hormone called Luteinising Hormone have also increased. The dosage used was 225 mg used three times a day.

  • Another study on 72 men with diagnosed erectile dysfunction divided into WS & placebo group found that men taking WS 4*500mg extract 3 times a day (6 grams total) for 8 weeks had some benefits; however, similar benefits were found in the placebo group hence, it was possible that improvements in both groups were due to factors other than the herbal extract.

  • 3 more studies (75, 180 and 75 participants) on men with medically diagnosed infertility who took 5g WS extract for 3 months found improved sperm production, improved sperm quality, reduced sperm destruction through oxidative stress in the seminal vesicles ( where sperm is made) and improved semen volume. WS has also been shown to upregulate markers of detoxification in the body and so it may be used in removing spermatotoxic components.


[for curious reader] What does male ejaculate consist of?

The ejaculate is not made of only sperm; in fact, sperm is less than 5% of the total ejaculated content. The content consists of the 4 crucial elements

  • Sperm (<5% ejaculate volume) made in testis (testicles). This is what carries 1/2 of the DNA of future offspring and a copy of our entire genome.

  • Seminal Fluid (up to 65% ejaculate volume) made in seminal vesicles containing amino acids and essential nutrients to ensure sperm survival inside the slightly acidic female vagina

  • Prostatic fluid (about 25% volume) is made in the prostate gland adding zinc and specific enzymes that help break down the outer layer of the female egg and allow sperm penetration. The prostate gland also helps to increase the ejaculatory force through a physical contraction during orgasm.

  • Bulbourethral fluid (about 5%) most of this is made to lubricate the final part of the urethra (peeing canal) and neutralise any leftover acidic urine (this is also commonly referred to as pre-cum).

Aswagandha & testosterone in men

Probably the most information on social media in relation to Aswagandha are claims on testosterone. Everything from “Aswagandha helps men grow bigger penis” to “Aswagandha boosts testosterone, muscle growth and causes weight loss” have been shared on Instagram, Tic Tock and Youtube.


But how much do we really know from human data? Not mice. Not in-vitro. Not other animals. Human data. There are currently only 3 human clinical studies in existence that looked at testosterone in relation to Aswagandha either directly or indirectly. Let’s break them apart.


Study 1 (Lopresi et al. 2019.)

Double-blind, randomised placebo study from India.

60 men & women were randomly divided into WS group (250mg/d) or the placebo group for 60 days. Doctors wanted to see the effect of WS on stress and major stress markers. As a secondary marker, they also looked at DHEA & Testosterone, two major sex hormones in men.


Before we begin, there are a few essential things to bear in mind here:

1. The study participants were people with an already ongoing degree of pre-existing depression and anxiety (these were not your typical chilled gym-goers).

2. The second thing to bear in mind is that the aim of the study was to assess the impact of WS on stress and mental health, not on testosterone; hence the primary design was to investigate the earlier, not the latter.

3. And the final thing to bear in mind is that people who are depressed or chronically stressed often have decreased (below optimal) levels of testosterone.


What were the results of study 1

1. Depression, anxiety and self-perceived stress have improved dramatically in the WS group compared to little-to-no improvement in placebo

2. Compared to placebo, a significant 23% reduction in cortisol was seen in the group group taking WS extract

3. DHEA, an important hormone that serves as a precursor of testosterone, has been reduced. In this case, the increased baseline DHEA could have indicated high-stress levels as cortisol often also increases DHEA along with it when people experience chronic stress or anxieties.

4. Testosterone in men has increased by 11%, but not in women. However, the increase was not statistically significant, which means the results might have happened by chance rather than as an effect of WS. This is possibly due to the small study size. While this result is promising, more research is needed


Summary of study 1

WS has shown significant improvement of mood and stress, mild improvement of levels of cortisol and DHEA and statistically insignificant increase of testosterone in men.


Study 2 (Lopresti et al. 2019 – same author, same year)

57 overweight men experiencing fatigue and stress were randomly divided into the experimental group (WS group) and placebo. Halfway through, they switched, experimental became placebo and placebo became experimental.


Study Results

Experimental group taking WS had improvement in fatigue and in vigour. They also had mild improvement in testosterone. But this study had many limitations. First of all, overweight men are already at an increased risk of reduced testosterone due to excess fat tissue that peripherally converts testosterone into oestrogens through a process called aromatisation (more on this in future posts)


Secondly, participants were recruited through social media, which could have been an important bias factor. Thirdly it was impossible to control for lifestyle & dietary factors, and so changes could have been caused by something else (for example, if one knows they are taking something that may increase testosterone, they will be likely to google and do other things that will increase it to maximise the potential benefit such as exercising more, taking other performance-enhancing supplements, changing diet etc).


Despite all of that, this study shows a promising effect of WS for overweight men who experience a decline in libido, mood and energy but more research is needed to be able to tell for sure.


Study 3 (Wankhede et al. 2015)

Behold the trial that shook the internet. 57 healthy adult males recruited from local gyms in Kolkata, India, were randomly divided into experimental group and placebo group. Participants in the experimental group took 300mg capsule of WS root extract called KSM-66 twice a day.


Both groups were asked to perform a specific routine of resistance training, including both compound and isolated lifts guided by trained professionals. They trained 3 times a week for 8 weeks. The aim was to progressively increase overload by gradually aiming for higher and higher weights and fewer repetitions. Researchers were looking at:

  • changes in strength

  • changes in muscle mass

  • changes in body fat

  • changes in post-workout recovery efficiency

What happened after 8 weeks?

  • Both groups had a significant increase in muscle strength but the experimental group taking WS extract had significantly higher improved their bench-press and leg-extension performance.

  • Both groups experienced hypertrophy of the chest, tights and arms, but the WS group experienced slightly more gains than the placebo

  • Both groups experienced weight loss, but there was no significant difference between experimental and placebo

  • Both groups experienced an increase in testosterone. But where placebo only had a little increase, the WS group had a significant testosterone spike going from 630 ng/dL on average all the way to 730 ng/dL.

  • Post-workout recovery was much greater in both groups but a bit better in WS group.


The results were super exciting, but there are a few limitations to bear in mind:

  • The participants in this study were new to the gym. When newbie embarks on a radical protocol supervised by a qualified trainer, their strength and muscles grow exponentially during the first six months. For example, the average 1-rep-max for bench press in both groups was around 33 kilos. This is a performance we would expect of an untrained adult who has never bench-pressed in his life.

  • It is possible that if the study was longer (>8 weeks) we would see a gradual halt of the results in both groups. Maybe what saw was mainly the period of major hypertrophy induced by rapid adaptation to a high level of mechanical stimulation, and then over time, this would be halted in both groups.

  • It would be interesting to see another study where KSM-66 was given to trained athletes. So far, all the studies to see if there would be a between-group difference there.

  • Note also that the age of individuals varied from 18-50, which would present radically different levels of strength, body fat and baseline testosterone levels. Averaging all of these data out has, in a way, removed the individual intra-group differences. For example, if it turned out that young people more than older benefit from WS, we wouldn’t have seen the effect here.



So what to we make of all this?

Based on the data presented, it is possible that men experiencing fertility problems may benefit from taking up to 1000mgh per day in split doses. Furthermore, while this approach is not guaranteed to do anything, it may help some people. We do not yet know what the mechanism for this is, but WS appears to normalise the function of the HPO (hypothalamic-pituitary-gonadal) axis, the key regulator of sex hormone balance.


Additionally, as shown in Part 1, WS also helps people reduce levels of the stress hormone cortisol and normalise anxiety levels. Men who are chronically stressed often experience a lack of libido and erectile problems, and if the stress can be removed, sexual desire and performance may come back


In terms of testosterone, the amount of data is still meagre, and it would be haste to make any major assumptions. But unsurprisingly, it hasn’t taken long for the market to catch up, and the supplement stores are now flooded with Aswagandha KSM-66 claiming anything from hyper-metabolic effects to super-human levels of testosterone and masculinity.


Let's take a step back and critically assess these 3 articles one more time:


1. Only one of those 3 studies was done on people who were otherwise healthy. The other two were done on chronically anxious and overweight individuals, both conditions are already confounders (can mix results) for low testosterone


2. All those studies are tiny, and that may cause an issue with the statistical significance. This means that there is always a chance that results were achieved by causes other than the intervention (Aswagandha supplementation)


3. All of them were pretty short in terms of time and we would need to see long term data. Perhaps two months later, those values would come back to normal