Ashwagandha and Shilajit, Compared on What Was Measured

Ashwagandha and shilajit are sold together so often, including in one of our own capsules, that people assume they do the same thing. They do not. Ashwagandha is a root extract of Withania somnifera whose trials measured perceived stress, anxiety scores, sleep and morning cortisol over six to ten weeks. Shilajit is a humic resin from mountain rock whose trials measured androgens in middle-aged men, strength retention after fatigue in young men and bone density in postmenopausal women. The two literatures barely touch, and no trial has ever tested the combination. That is the honest basis for a comparison, and everything below follows from it.

“Adaptogen” is the word that makes the pairing feel natural, so it is worth saying up front what the word is and is not. It is a category, not a mechanism, and in the EU it is not a regulatory category at all.

What “adaptogen” means, and what it does not license

The term was coined by the Soviet toxicologist N. V. Lazarev in 1947 for a substance claimed to raise “non-specific” resistance to adverse influences and stress, and it was given a working definition by Brekhman and Dardymov two decades later. The European Medicines Agency’s 2008 reflection paper on the adaptogenic concept sets out that definition in four parts: an adaptogen is almost non-toxic; it is non-specific, raising resistance to a broad range of biological, chemical and physical stressors; it tends to normalise rather than push in one direction; and its effect is greater the more disturbed the organism is. The agency’s conclusion is the part nobody quotes: “the term is not accepted in pharmacological and clinical terminology that is commonly used in the EU”, and the clinical data behind the concept have “a number of shortcomings”.

So two things can be adaptogens in the marketing sense and have been studied for completely different outcomes, which is exactly the case here. What are adaptogens ranks eight of them by the weight of evidence; this article takes two and puts them side by side.

The comparison, on what was actually measured

	Ashwagandha	Shilajit
What it is	Root extract of Withania somnifera, a nightshade	Humic resin exuded from high-altitude rock, mostly fulvic and humic acid
Named extracts in trials	KSM-66, Sensoril, Shoden, unbranded high-concentration root extracts	PrimaVie standardised extract in several trials; purified resin in others
Doses in trials	240 mg to 600 mg per day of extract	250 mg to 1,000 mg per day
Trial lengths	6 to 10 weeks typically; one 12 month observational study	28 days to 48 weeks
Populations	Stressed healthy adults, adults with insomnia	Men aged 45 to 55; young trained men; postmenopausal women with osteopenia
Outcomes measured	Perceived stress scale, anxiety scales, sleep onset and efficiency, serum and salivary cortisol	Total and free testosterone, DHEAS, strength decline after fatigue, collagen marker, bone mineral density
Combination trialled	Never, together	Never, together
Regulatory position	German BfR advises against use; restricted in Denmark; legal elsewhere in the EU	Legal as a food supplement in the EU; not novel in supplements

The table is the article. The rest is the detail behind each row.

Ashwagandha: what the trials measured

The trial everyone cites is Chandrasekhar and colleagues, 2012, in the Indian Journal of Psychological Medicine. Sixty-four adults with a history of chronic stress took either placebo or 300 mg of a high-concentration full-spectrum root extract twice a day for 60 days. Scores on the stress scales fell further in the ashwagandha group than on placebo, and serum cortisol was lower in the ashwagandha group at day 60. Adverse effects were mild and similar in both groups.

Three later trials shape the dose question. Salve and colleagues, 2019, in Cureus, gave 60 stressed healthy adults 125 mg or 300 mg of root extract twice daily, so 250 mg or 600 mg per day, or placebo for eight weeks; perceived stress fell at both doses, serum cortisol fell at both doses, and the 600 mg group showed the larger changes. Lopresti and colleagues, 2019, in Medicine, gave 60 stressed adults 240 mg of the Shoden extract once daily for 60 days and reported lower anxiety scores and lower morning cortisol than placebo, with no adverse events; testosterone rose in men over time but not significantly against placebo. Langade and colleagues, 2019, in Cureus, gave 300 mg of root extract twice daily to adults with insomnia for ten weeks and measured sleep with actigraphy: sleep onset latency was shorter and sleep efficiency higher than placebo.

Notice the shape of that evidence. The trials are consistent with each other, they measured questionnaire scores and a hormone, they ran for two or three months, and they were mostly done in India in groups of about sixty. What the ashwagandha literature is and is not, including the liver case reports and the position country by country, is in ashwagandha benefits and side effects, and the dose and timing detail is in ashwagandha dosage and timing. The cortisol question on its own is in ashwagandha and cortisol.

Shilajit: what the trials measured

Pandit and colleagues, 2016, in Andrologia, ran a randomised, double-blind, placebo-controlled trial in healthy men aged 45 to 55 at a state Ayurvedic college in Kolkata: 250 mg of purified shilajit twice daily for 90 days, with total testosterone, free testosterone and DHEAS higher than placebo at the end and LH and FSH maintained. That trial is the load-bearing citation for most of what is written about shilajit for men, and it is one trial in one age band.

Keller and colleagues, 2019, in the Journal of the International Society of Sports Nutrition, gave 63 recreationally active men, mean age 21, either 250 mg or 500 mg daily or placebo for eight weeks and then a fatiguing protocol of maximal leg extensions. The 500 mg group lost less maximal strength after the protocol than placebo, but only in the upper half of the sample by baseline strength, and the 250 mg arm did not differ from placebo at all.

The longest trial, 48 weeks in postmenopausal women with osteopenia, measured bone mineral density; a handful of others measured gene expression in muscle and skin, a collagen synthesis marker and time to bone union after surgery. Every one is audited in shilajit benefits. What shilajit is, geologically and chemically, is in the definition page.

Set the two lists beside each other and the point makes itself. Ashwagandha trials measured how stressed people said they felt and one stress hormone. Shilajit trials measured androgens, a strength test and a bone scan. There is no outcome that both were tested on, so there is no sense in which one is “stronger” than the other. They are answers to different questions.

Does pairing them make sense?

The argument for pairing is that the outcomes barely overlap, so there is no obvious reason to expect one to interfere with the other, and a person might reasonably want both. That is a reasonable expectation. It is not a finding, because nobody has tested it: no published trial has given ashwagandha and shilajit together and measured anything.

Two cautions follow from that gap. First, the absence of a reported interaction is not evidence of safety; it is evidence that nobody has looked. Both substances have hormonal signals in their trial literature, ashwagandha on cortisol and shilajit on androgens, and what two hormonal signals do together in one person has not been studied. Second, the practical problem. If you start both on the same day and feel different a month later, you have no way of knowing which one did it, or whether either did. That matters because the sensible next step, stopping the one that did nothing, is unavailable to you.

Our advice, which costs us a sale of the combined capsule, is to start with one. Pick the one whose trials measured the thing you are actually interested in. Run it for a month at the trial dose, as described for shilajit here. Then decide whether to add the other, and if you do, add it on its own for a second month before judging the pair. The combined capsule exists for the person who has done that and wants one bottle instead of two.

The testosterone question underneath the search

A large share of the people who search for ashwagandha with shilajit are searching for one thing, so it is better answered than avoided. Both substances have a testosterone signal somewhere in their trial literature, and both signals are smaller and narrower than the marketing built on them.

For shilajit, the signal is the 2016 Andrologia trial described above: higher total and free testosterone and DHEAS than placebo after 90 days at 500 mg per day, in healthy men aged 45 to 55, in one trial. A 2024 systematic review of marketed “testosterone boosters”, discussed in shilajit for men, rated purified shilajit as possibly effective in one population only, men with late-onset hypogonadism, and found that most products in the category do not raise total testosterone at all.

For ashwagandha, the signal is weaker still. In the Lopresti trial, testosterone rose in men over the 60 days, but the change was not statistically different from placebo. Other ashwagandha trials that measured it are small and mostly in specific groups, and the BfR lists effects on sex hormones among the reasons for caution rather than among the benefits.

So the honest summary is that one trial in middle-aged men found an androgen difference on shilajit, no trial has found one on ashwagandha against placebo, and no trial has measured the pair. Neither substance may be sold in the EU with a claim about testosterone, and we do not make one.

If you do take both: dose, timing and format

Nothing in the literature describes a combined dose, so the only defensible approach is to keep each at its own trial dose and not to reason that two substances at half dose add up to one effect.

For ashwagandha, the trial doses are 240 mg of Shoden once daily, 250 mg or 600 mg of root extract split into two, or 300 mg of a high-concentration extract twice daily, always tied to a named extract and its standardisation; a milligram figure without an extract name is not comparable to any of them, as the dosage article explains. For shilajit, 250 mg to 500 mg of purified resin once daily is the range most trials used.

Timing was not compared in any trial for either substance. Ashwagandha has been given in the morning, split across the day and half an hour before bed in different studies; shilajit is conventionally taken in the morning. If you take both, the simplest pattern that matches the trials is shilajit in the morning in warm water and ashwagandha with the evening meal, which also keeps the two a few hours apart so that any digestive complaint can be attributed to one of them.

On format, there are three ways to do this: resin plus a separate ashwagandha capsule, which gives you the resin’s laboratory certificate and a named extract on the capsule; the combined capsule, which gives you convenience and a stated amount of each in one bottle; or the resin and combined-capsule bundle for someone who wants both. The trade-off is the same as everywhere on this site: the resin is the product with the batch certificate, the capsules are the products with the measured dose.

Who should avoid ashwagandha

This is the row of the table that has moved most in the last two years, and the honest comparison has to include it. The German Federal Institute for Risk Assessment, the BfR, published Mitteilung 039/2024 on 10 September 2024 under a title that translates as “Ashwagandha: sleepberry preparations with possible health risks”. Its recommendation is specific: children, pregnant and breastfeeding women, and anyone with a current or previous liver condition should not take ashwagandha preparations, and because of the gaps in the data the institute also advises the rest of the population to exercise restraint. The BfR notes that the human studies were designed to look for benefits and did not systematically record adverse effects, that there are case reports of liver damage possibly linked to ashwagandha products, and that the preparations may affect the endocrine system, including cortisol, blood sugar, thyroid and sex hormones. It records that the Danish, Dutch, French and Australian authorities reached compatible conclusions between 2020 and 2024.

That is a national risk assessment body, not a blog. Anyone on thyroid medication, sedatives, antidiabetic medicines or immunosuppressants should speak to a doctor before taking ashwagandha, and anyone with a liver condition should not take it at all. The full country-by-country position, including Denmark’s restriction, is in ashwagandha benefits and side effects.

Who should avoid shilajit

The exclusions are different, which is itself a reason not to treat the two as one product.

Iron-overload conditions. Shilajit is iron-bearing. Anyone with haemochromatosis or another iron-overload diagnosis should not take it.

Pregnancy and breastfeeding. A 2018 case report in Gynecological Endocrinology describes a 37-year-old pregnant woman with persistent hypertension and low potassium after six months of mumijo, diagnosed as a licorice-like syndrome that resolved on stopping. No trial has recruited pregnant women. Avoid.

Children. Not tested. Not for them.

Untested material. Raw shilajit can carry lead, arsenic and mercury, and the contamination literature is stronger than the efficacy literature. The EU limits, and what a batch certificate has to show, are in the heavy metals article.

Prescribed medication. No interaction studies exist for shilajit, none for ashwagandha with shilajit, and the two together compound the uncertainty. Ask a doctor or pharmacist first.

Neither substance is authorised for any health claim in the EU under Regulation (EC) 1924/2006, and nothing above should be read as a claim that either acts on any condition.

What the combined capsule is, and is not

Our ashwagandha and shilajit capsule contains a stated amount of each, printed on the label, in a vegan capsule, and the product page states the composition and directions. It is a convenience format for someone who has decided to take both. It is not a tested combination, and we do not describe it as one: the capsule blends carry no third-party laboratory certificate of their own, and the resin’s certificate applies to the resin only. If the laboratory evidence is what you are buying, the resin is the product with the document behind it.

The short version

Ashwagandha and shilajit are two different substances with two different trial literatures and no shared outcome. Ashwagandha, 240 mg to 600 mg of extract a day over six to ten weeks, moved stress and anxiety scores, sleep measures and cortisol in groups of about sixty; the German BfR now advises against it for children, pregnant and breastfeeding women and anyone with a liver history. Shilajit, 250 mg to 1,000 mg a day over eight to 48 weeks, moved androgen levels in men aged 45 to 55, a strength test in young men and bone density in postmenopausal women; it is not for anyone with an iron-overload condition or in pregnancy. The combination has never been trialled. Start with one, run a month, then decide.

From here, what shilajit is and how to take it cover the resin side, fulvic acid is the chemistry, and what are adaptogens puts both in the wider category.