Ashwagandha and testosterone: what the trials measured in athletes

In the best known trial, testosterone rose by 96.2 ng/dL on ashwagandha against 18.0 ng/dL on placebo. Converted to the unit Dutch labs use, that is roughly 3.3 nmol/L. It came on top of eight weeks of resistance training, because both groups trained.

That conversion is missing from almost every page quoting this study. And without it you cannot lay the figure next to your own result.

Does ashwagandha raise your testosterone?

In two trials testosterone rose significantly against placebo, but they measured it in different body fluids. In 57 young men doing eight weeks of resistance training, serum testosterone rose by 96.2 ng/dL against 18.0 ng/dL on placebo (Wankhede, 2015).

In men aged 40 to 70, salivary testosterone rose by 14.7 percent (Lopresti, 2019).

Both significant, both real. But they are two different measurements, and that gets confused almost every time.

Why serum and saliva do not add up

Serum testosterone is what your GP or a blood test measures: the total in your blood, in nmol/L. Salivary testosterone approximates the free fraction and is reported in pmol/L. The numbers sit on different scales and do not describe the same thing.

So a 14.7 percent rise in saliva does not predict 14.7 percent on your blood result.

Quoting both studies back to back as evidence for one effect stacks two measurements that do not stack. How total and free testosterone relate is covered in testosterone and muscle mass.

What does 3.3 nmol/L mean on your report?

Take two men both training seriously for 8 weeks: one sits at 15 nmol/L, the other at 22 nmol/L. In both, a shift of 3.3 nmol/L would stay inside the same reference range.

For the first that is a noticeable relative change, roughly a fifth on top.

For the second it largely disappears into the normal variation between two draws. The same rise therefore means something different per person, which is exactly why a percentage without a baseline says little.

You can find your own baseline through total testosterone.

What else the trial measured

Testosterone was not the primary outcome in that trial. The primary measure was muscle strength, and the differences there were larger than in the hormone.

Look at the placebo column. That group also got considerably stronger, because they trained just as hard for eight weeks.

Training did most of the work. That is the context which disappears when an advert shows only the first column.

Does ashwagandha affect your libido?

This is where the picture is weakest. In the crossover study in men aged 40 to 70, sexual wellbeing was asked about explicitly, and there was no significant difference against placebo. The same held for fatigue, vigour and mood.

The hormones moved; the feeling did not.

What users report themselves diverges from that, and the tension is worked through in ashwagandha reviews.

What raises testosterone most?

Judging by the size of the measured effects, a supplement is not at the top. Sleep, body composition and consistent resistance training track your value more strongly than anything in a jar. In this trial both groups trained, and the placebo group saw its testosterone rise too.

That detail is rarely quoted and it is the most important number in the table.

What else has been studied is covered in raising testosterone naturally.

What you can do with this

My own conclusion is sober. The effect was genuinely measured, it is small next to what training itself does, and RIVM advises against the supplement after reports of liver injury.

If you want to know whether anything changes in you, measure before and after. A single result without a starting point says little, because testosterone swings by day and by time of day.

The full picture, thyroid and liver included, is in the ashwagandha overview. Discuss any result that comes back off with your GP.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

References

• RIVM. Advice on products containing Huperzia serrata, Tabernanthe iboga or ashwagandha. 5 March 2024.
• Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. J Int Soc Sports Nutr. 2015 (PMID 26609282).
• Lopresti AL, Drummond PD, Smith SJ. Am J Mens Health. 2019 (PMID 30854916).
• Chandrasekhar K, Kapoor J, Anishetty S. Indian J Psychol Med. 2012 (PMID 23439798).