Ashwagandha raises testosterone. Here's why I don't take it.

This wonder supplement does so many things that it's no wonder some feel its a lifesaver while others experience debilitating side effects.

In this article, we’ll do a deep dive on:
・What ashwagandha does
・Unexpected side effects from it
・Dosing
・Cycling
・Why the individual responses to it are so different
・How exactly ashwagandha works
・Recommended brands if you want to experiment anyway

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Ashwagandha at a glance

Reasonable expectation: approx 54 ng/dL increase in testosterone over 60 days.¹
Starting Dose: 240mg once a day (ashwagandha extract).²
Timing: Avoid mornings.
Cycling: 2 weeks on 2 weeks off.
Side effects: Relatively low chance, but potentially dramatic. Risk increases the longer you take it.

Do I take it? No.

Have I taken it? Yes. It made me feel …strange - jittery and slightly nauseous.

△Given the potential risks and the fact that it acts on so many different systems, I personally wouldn’t take it regularly as a testosterone booster. I may try it for a very short period of time if I am having trouble with anxiety or sleeping due to some acute stressor.

What does it do?

• Increases testosterone (by potentially 45-90 ng/dL)

• Reduces cortisol (by up to 28%)³

• Improves subjective anxiety, depression and stress (One study found it to reduce the score on a depression-anxiety stress scale by 71.6% and perceived stress by 44%.)

• Improves sleep (up to 50 minute increase in sleep time, 12 minute decrease in time to fall asleep)⁴

• May improve endurance (vo2max)

Sounds great enough to just hop on amazon and drop $30 bucks on a bottle real quick, right?

Debilitating side effects

While the overall occurrence of side effects appears to be quite rare, many users online have reported debilitating side effects from using ashwagandha. One reddit user claimed it worsened his depression after just 10 days of taking it and another user claimed they felt ‘so fucken empty and sad’ after just taking it once. While small, the potential for side effects illustrates highlights the things worth understanding about ashwagandha:

・Why you should be careful with the dose
・Why you should cycle it
・Why you should pay close attention as the individual responses can be dramatically different.

Let’s do a dive into the why on each of these.

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Dosing

There are a bunch of products on the market provided in various doses. This KSM-66 Ashwagandha Root Powder Extract is dosed at 1000mg twice per day - this is anywhere from 3-8 times the effective dosed used in many trials. Denmark banned ashwagandha in April 2023, claiming that it is impossible to find a safe dose given the current data. Given the potential for side effects and the apparent diminishing returns on benefits from higher doses, it would be wise to start with the lowest effective dose. Personally I’m unimpressed with Bryan Johnson’s longevity mix containing 600mg of ashwagandha with no warning to cycle it.

💪Testosterone

In the two randomized, double-blind trials on healthy adults, 240mg of ashwagandha extract achieved an increase of 54ng/dL of testosterone. The other trial used more than twice that dose (300mg ashwagandha root extract twice daily) to achieve only another +24ng/dL of testosterone (+78ng/dL total).

😬Stress Reduction

Further, a trial investigating the cortisol lowering effect of ashwagandha found 125mg of root leaf extract twice daily for 60 days to be almost as good as 250mg twice daily (-24.2% vs. -30.5%)

😴Sleep

Another study in healthy adults found sleep quality to improve significantly with 250mg of ashwagandha extract a day with better improvements from 600mg per day.

△Based on this, 250mg of ashwagandha extract seems to be the prudent dose as these had a significant effect on testosterone, stress reduction and sleep improvement.

However, you should keep an eye on the type of product you’re getting. Where some trials used ashwagandha extract, others trials use root powder. With root powder they generally use much higher doses - one trial was using 5 grams of it (which exceeds the maximum of 3g of root powder set by polish authorities). Then, depending on the brand you get you’re going to have different concentrations of the different bioactive compounds. There are extracts with no particular specifics but there’s also extracts that are standardized to 3.5% withanolides or KSM-66 ashwagandha extract which apparently ‘maintains the balance of the active components found naturally in the herb.’ Further, there are different varieties of ashwagandha plants themselves with varying amounts of active compounds.

Simply put, you may respond very differently to one brand compared to another.

Cycling

Cycling is where you take the supplement for a certain period of time, then stop it for a certain period of time before restarting. This is to mitigate side effects and maintain beneficial effects.

To my knowledge, there are no trials investigating what cycling protocol is best for ashwagandha. The trials investigating the effects of ashwagandha in humans have been over 4-12 weeks.

Andrew Huberman has recommended 2 weeks on 2 weeks off as well as 2-3 weeks on, 1-2 weeks off. Nicole M. Avena, an assistant professor of neuroscience at Mount Sinai School of Medicine has said that stopping using the supplement after 3 months will reduce the risk of severe side effects. She is likely basing this on the fact that there are no human trials that lasted longer than 3 months.

・　Given the potential for side effects, I would at least go for the more prudent 2 weeks on, 2 weeks off approach.

One case report found that where 10 weeks of ashwagandha supplementation lead to excessively suppressed function of the adrenals, a 2 week break was enough to reverse this.

Now there’s going to be a lot of individual variability. You see anecdotes of people saying they feel like crap on it after just 10 days. If we’re to put any stock into such anecdotes, perhaps going off after as little as 10 days would be a good idea.

Ashwagandha contains both water-soluble and fat-soluble compounds⁵, which means that some compounds in ashwagandha may remain in your system for up to a month, depending on how much you’ve been taking and for how long. In a case report where a woman experienced a ‘thyroid storm’ after taking 1950mg of ashwagandha root extract for 2 months, her thyroid levels were still abnormal at 20 days. Since they weren’t testing her blood frequently, we don’t know the exact point at which everything returned to normal. Perhaps a month (or more) break every now and then would be wise.

Why is the response so different from person to person?

If you look on the comments section of the Good Morning America video about the potential side effects of ashwagandha, you will see plenty of comments from people talking about how it changed their life.

So why do you have on one hand people warning others about debilitating side effects while others are so impressed by its effects that they view any warnings against it as a ploy from the pharmaceutical industry?

Ashwagandha is doing a lot

△ Perhaps if you don’t have ‘enough’ GABA, serotonin and thyroid activity and you have too much cortisol, then ashwagandha may be valuable.

I understand all these mechanistic details may feel like an annoying foray into the weeds, but at least do a glance-over to get an idea of just how complicated the action of ashwagandha is.⁶

The evidence suggest that ashwagandha may:

・Stimulate GnRH neurons.(S)
・Increase serotonin levels.(S)⁷
・Increase dopamine levels and a dopamine metabolite.(S)⁸
・Act as a GABA mimetic.
・Increase GABA_A, GABA_B1, and serotonin (5HT_1A) receptors
・Enhance the functional sensitivity of 5HT₂ receptors and 5HT_1A receptors.(S, S2)
・(due to its withanolide content) reduce cortisol indirectly by reducing inflammation.(S)
・ Reduce cortisol by reducing HPA axis activation through its effect on GABA and serotonergic pathways.(S)⁹
・Significantly increase the thyroid hormones T3 and T4 which seems to have the effect of reducing your body’s production of TSH.(S, S2)¹⁰

What the hell does all that mean?

・The stimulation of GnRH would raise testosterone.
・The increase in serotonin would have many effects but according to the serotonin theory of depression, it should have an antidepressant effect. At the same time, the serotonin increasing effect of ashwagandha may explain why some people experience an emotional blunting similar to that experienced with SSRI usage.
・An increase in dopamine levels would increase subjective motivation as well as motivation to act.
・The GABA mimetic activity would increase relaxation and aid in sleep.
・An increase in GABA_A& GABA_B1 receptor activity may have a sedative effect and the GABA_B1 receptor may be responsible for reduced emotional intensity/emotional blunting from ashwagandha.
・The effect on 5HT₂ and 5HT_1A receptors may be involved in the antidepressant effects of ashwagandha.
・Reduction in cortisol would lead to a reduction in stress and may contribute to the increase in testosterone. Cholesterol can either be turned into cortisol or testosterone. Less cortisol may make more precursors available for testosterone production.
・An increase in the thyroid hormones T3 and T4 would have a stimulating effect.

You might have noticed that some of these are quite contradictory. We typically associate testosterone, dopamine and thyroid hormones with more ‘vigor’ in general yet at the same time, ashwagandha is supposed to calm you down and help you sleep. In fact, the latin name of ashwagandha is withania somnifera. Somnifera means ‘sleep-inducing’ in latin.

By looking at the mechanisms we can take some guesses about how to approach ashwagandha use. For example, you might not want to combine it with other compounds like kava which also stimulates GABA_A as you may exacerbate your risk for the drowsy, sedated feeling people have complained about.

https://dutchtest.com/blog/recovering-from-stress-after-the-holidays/

While we don’t like stress, it is very useful. If you had absolutely no stress you might not have any motivation to actually do anything because what’s the point? If you don’t feel an issue with anything then why try and do any work to change anything. People with Addison’s disease, a disease characterized by abnormally low cortisol, experience a lack of energy and motivation as well as abnormal drowsiness. The Cortisol Awakening Response (CAR) refers to a normal, natural elevation in cortisol in the morning. The idea is that it will wake you up and enhance your motivation to go out and tackle the day. For this reason it is probably better to avoid taking ashwagandha in the morning as ashwagandha’s potent cortisol-lowering effect may interfere with the cortisol awakening response and blunt your body’s built-in cup of coffee.

Further, ashwagandha might be helpful if you are having trouble sleeping from drinking too much caffeine as one study in mice found that it ‘effectively relieved caffeine-induced insomnia symptoms.’ In this study, a dose of ashwagandha was given just 40 minutes before inducing sleep in the mice. They found that in the mice hopped up on caffeine, more ashwagandha lead to longer sleep duration. Further, another rodent study found that it protected the brain against some of the negative effects of sleep deprivation.

The various contradictory results in the literature also reveals the importance of acknowledging the individual variation in response to ashwagandha. At least one study found that patients on SSRI’s fared better with 1000mg of ashwagandha extract per day. Yet at the same time, another study warns that clinicians need to be aware of the adverse events associated with using antidepressant drugs in combination with adaptogens like ashwagandha. Ashwagandha seems to increase the concentration of and risk for side effects with the antidepressants Reboxetine, Sertraline, Escitalopram, Parotexine.(S)

Ashwagandha seems to be so powerful in stimulating thyroid hormones that one man experienced a ‘thyroid storm’ (a life threatening complication of hyperthyroidism) after taking ashwagandha for 2 years in order to treat his hypothyroidism. This is at least the third report of thyroid storm from ashwagandha.

The ashwagandha lowered his TSH to where it was barely detectable but it returned to the normal range after 2 weeks and was still increasing at 5 weeks.

Here is another contradictory point about ashwagandha. I mentioned that you might want to avoid taking it mornings because it may dampen your motivation, but if it stimulates your thyroid hormones more than you can tolerate, then that may interfere with your sleep.

So, with all these different things going on, I’m not surprised that it made me feel weird. I first tried it out because I liked the idea of boosting my testosterone a little bit. I didn’t get debilitating side effects or anhedonia or anything like that, I just felt mildly uneasy, hot and slightly queasy. I didn’t really see the point in pushing through this and continuing to take it considering I don’t have an issue with stress, sleep and I don’t have low testosterone.

If you’re a generally healthy person who doesn’t have trouble with stress, sleeping or thyroid production and you’d just like a little boost in testosterone, I would still avoid ashwagandha. If you do decide to experiment with it, I hope this post at least allows you to be more vigilant about side effects.

We can also surmise that people taking say benzodiazepines or SSRIs should be extra cautious with ashwagandha and people with hyperthyroid conditions like Graves disease, people with low cortisol like Addison’s disease and pregnant women (may carry a risk of spontaneous abortion) should not take it.

If you are taking other supplements or medications, it would be wise to investigate whether these interact with or have effects similar to ashwangandha that might compound the effect.

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I don’t care, I want to experiment. Brands?

KSM-66 ashwagandha is the most studied form of ashwagandha on the market so you at least have the confidence that the compound you’re getting is very similar* to what these people in the trials received.

*I say very similar because as mentioned earlier, the plants themselves could have slightly different amounts of bioactive compounds depending on growing conditions, time of harvest etc.

For example this 2013 study found that men with a low sperm count receiving 675mg of KSM-66 ashwagandha root extract experienced a +77ng/dL increase in testosterone after 90 days as well as a 167% increase in sperm count. There are also at least 20 other studies evaluating KSM-66 on various other outcomes like respiratory endurance, muscle strength, stress and weight management, memory and cognition, and quality of sleep.

It is also low in withanolide A which is cytotoxic.

So if I were going to take ashwagandha I would pick one of the brands listed on the website for ksm-66. (Jarrow labs, Thorne and Nootropics depot are three brands I trust. However, I would prefer to be able to dose it by itself so I would skip on Thorne as they only have it as part of formulations.) I would take 250-300mg for 2 weeks and if the effects were completely unnoticeable I would then cycle off for 2 weeks then do another 2 weeks on at about 600mg.

1. Two randomized, double-blind trials have been done on healthy adults.(S, S2) There are at least 5 other studies in infertile or overweight men showing that ashwagandha raises testosterone.(S,S2,S3,S4,S5) Infertile or not, the testosterone raising effect was similar: +45 to approximately +90ng/dL after taking it for 2-3 months.

2. This is based on the fact that in the two randomized, double-blind trials on healthy adults, 240mg of ashwagandha extract achieved an increase of 54ng/dL of testosterone. The other trial used more than twice that dose (300mg ashwagandha root extract twice daily) to achieve only another +24ng/dL of testosterone (+78ng/dL total). Given the potential for side effects and the apparent diminishing returns, it would be wise to start with this lower dose that has been shown to be effective. Further, a trial investigating the cortisol lowering effect of ashwagandha found 125mg of root leaf extract twice daily for 60 days to be almost as good as 250mg twice daily (-24.2% vs. -30.5%)

3. One study found that 125mg of ashwagandha root leaf extract over 60 days reduced cortisol by about 25% in chronically stressed individuals. It also dramatically lowered their rating on an anxiety scale. It took them from a score of about 28 to 8. Double the dose (250mg twice daily) took people from about 28 to about 6. Another study on 64 subjects with a history of chronic stress found that 300 mg of high-concentration full-spectrum extract from ashwagandha root twice a day lowered cortisol by 27.9%, score on a depression-anxiety stress scale by 71.6% and perceived stress by 44%. Another study on overweight, aging men found no significant changes in cortisol.

In one trial looking at 3 groups of men, the non-smokers, smokers and psychologically stressed mens’ cortisol was elevated by 22%, 88% and 129% from the start. 5 grams of ashwagandha root powder for 3 months reduced nonsmokers’ cortisol by 11%, smokers’ by 28% and psychologically stressed mens’ by 32%. So the total reduction in cortisol was greater the greater the stress level.

4. A 2019 study on people with insomnia found that 300mg of ‘capsule containing highest concentration full-spectrum Ashwagandha root extract’ twice daily in 40 subjects to improve total sleep time increased by 50 minutes and reduced time to fall asleep decreased by 12 minutes after 10 weeks of treatment. Another study in healthy adults found sleep quality to improve with 250mg of ashwagandha extract a day with better improvements from 600mg per day.

5. Bioactive compounds in ashwagandha are: Withaferin A, Withanolide A, Withanolide B, Withanolide C, Withanolide D, Withanone, Withanoside IV, Withanoside V

6. Ashwagandha also includes: alkaloids, steroidal lactones, β-sitosterol, scopoletin, sitoindosides, somniferiene, somniferinine, pseudotropine, anaferine, anahygrine, chlorogenic acid, cuscohygrine, withanine, withaferine, withanolides, withananine, tropanol, 6,7β-Epoxywithanon, 14-α-hydroxywithanone, etc.

7. One study titled A Standardized Withania somnifera (Linn.) Root Extract with Piperine Alleviates the Symptoms of Anxiety and Depression by Increasing Serotonin Levels: A Double-Blind, Randomized, Placebo-Controlled Study surmised that the reduction in anxiety and depression achieved with 90 days of 500mg ashwagandha root extract daily (with 5mg piperine) may have been thanks to its increasing serotonin 1.52x.

8. Ashwagandha has even been shown some promise for (a rodent model of) Parkinson’s, which is a disease of impaired dopamine function.(S) Ashwagandha increases the functional sensitivity of serotonin (5-HT2) receptors. There is evidence that stimulation of serotonin (5-HT2A) receptors increases the release of dopamine.(S) Other research suggests ashwagandha may have some promise for another dopamine related disorder - Huntington’s disease.

9. While several studies have presented a robust cortisol-lowering effect, other evidence suggests it has a cortisol-raising effect in certain circumstances.

10. Nutrition Library (great channel) surmised that one pathway through which ashwagandha raises testosterone may be by reducing TRH and TSH which then would reduce prolactin levels (prolactin antagonizes testosterone). However, this particular study found that ashwagandha didn’t affect prolactin levels. Authors of another study finding decreased sexual performance in rats suggested that ashwagandha has a prolactin-increasing effect.