Shilajit vs. Ashwagandha: What the Evidence Says About Each Adaptogen

Shilajit and ashwagandha are two of the most discussed supplements in the adaptogen category. Both originate in Ayurvedic medicine, both are marketed for energy and vitality, and both have a growing body of clinical research — though that research varies considerably in size, quality, and what it actually demonstrates.

This comparison lays out what each substance is, what mechanisms researchers have proposed, and what the current evidence suggests about their respective strengths. The goal is to help you match the supplement to your situation, not to declare a winner between two substances that serve meaningfully different purposes.

What Are Shilajit and Ashwagandha?

Shilajit is a dark, tar-like resin that seeps from rock crevices in mountain ranges including the Himalayas and Altai. It forms over centuries through the decomposition of plant matter compressed under rock. Its primary bioactive components include fulvic acid, humic acids, dibenzo-alpha-pyrones (DBPs), and more than 80 trace minerals. Researchers have proposed that fulvic acid may enhance the cellular uptake of nutrients and support mitochondrial function, while DBPs may participate in electron transfer during cellular energy production. Direct mechanistic evidence for these pathways in humans is still limited.

Ashwagandha (Withania somnifera) is the root of a small shrub native to India and parts of Africa. Its active constituents — primarily withanolides — are thought to modulate the hypothalamic-pituitary-adrenal (HPA) axis, which governs the body’s cortisol stress response. This proposed mechanism is why ashwagandha is most commonly studied in the context of stress, anxiety, and fatigue. Both supplements have small-to-moderate clinical trial bases; neither has been evaluated in large, long-term trials comparable to pharmaceutical standards.

Stress, Anxiety, and Fatigue: Ashwagandha Has the Stronger Evidence

Of the two, ashwagandha has been more extensively studied for psychological stress and fatigue. A randomized, double-blind, placebo-controlled trial found that a standardized ashwagandha extract significantly reduced self-reported stress and anxiety scores compared to placebo over eight weeks ^[4]. A more recent trial using a novel standardized extract (Witholytin®) similarly found meaningful reductions in perceived stress and fatigue in adults reporting high baseline stress levels ^[8].

Shilajit is not typically positioned as a stress-relief supplement and the research evidence for anxiety or cortisol reduction is sparse compared to ashwagandha. If managing psychological stress or generalized fatigue is your primary goal, ashwagandha has a more established trial base for that use.

Testosterone and Male Reproductive Health: Both Show Early Promise

Both supplements have been investigated in the context of male hormone health, though the evidence is preliminary for both. A placebo-controlled study in healthy male volunteers found that purified shilajit supplementation was associated with higher total testosterone levels compared to placebo over 90 days ^[2]. An earlier study found improvements in sperm parameters — including sperm count and motility — in men with oligospermia who took processed shilajit ^[1]. Additional studies suggest shilajit may exert protective effects on testicular function following exposure to certain toxins or chemotherapeutic agents [PMID 29947420, PMID 39121783], though the relevance of these findings to healthy adults using shilajit as a supplement is uncertain.

Ashwagandha has also been examined for effects on testosterone. A systematic review on herbs and testosterone concentrations noted that ashwagandha is among the more commonly studied botanicals in this area, though the review cautioned that effect sizes are modest and study quality varies ^[5]. A separate systematic review examining commercially marketed testosterone boosters concluded that evidence for meaningful serum testosterone increases from most supplements — including botanical ones — remains limited ^[7]. Both reviews serve as a reminder to approach hormone-related marketing claims with healthy skepticism.

Physical Performance and Muscle Recovery

Ashwagandha has reasonable controlled evidence for supporting resistance training outcomes. A randomized controlled trial in healthy adults found that ashwagandha supplementation was associated with significantly greater gains in muscle strength and recovery compared to placebo in people engaged in resistance training ^[3]. This positions it as a plausible adjunct for gym performance alongside a structured training program.

Shilajit’s performance evidence is less mature but growing. A recent open-label pilot study using TruBlk™ shilajit resin over 28 days reported improvements in physical performance measures and favorable changes in certain blood biomarkers in healthy adults ^[9]. Open-label pilot studies lack a placebo control group, which limits the conclusions that can be drawn — this represents an early signal, not a confirmed effect. More rigorous, controlled trials are needed before firm conclusions can be made about shilajit’s impact on physical performance.

Women's Health: Ashwagandha Has Been Studied; Shilajit Has Not

Ashwagandha has been studied specifically in women. A randomized, double-blind, placebo-controlled trial in perimenopausal women found that an ashwagandha root extract was associated with significant reductions in climacteric symptoms — including hot flashes, sleep disturbance, and anxiety — compared to placebo ^[6]. This is a meaningful data point for women approaching or in perimenopause who are exploring botanical support options.

Shilajit research has focused almost entirely on male reproductive health. There is currently no comparable clinical trial evidence for shilajit in women’s hormonal or reproductive health. Until that research exists, ashwagandha is the better-evidenced option for women with stress- or hormone-related concerns.

Safety, Purity, and Who Should Be Cautious

Shilajit carries a specific risk that ashwagandha does not: heavy metal contamination. Because shilajit is a mineral-dense resin harvested from rock, raw or inadequately processed products can contain elevated levels of lead, arsenic, mercury, or other heavy metals. Only purified, third-party-tested shilajit from reputable sources should be used. The 28-day pilot study on shilajit resin included blood biomarker monitoring and reported no adverse safety signals in healthy participants ^[9], but this was a short-duration, uncontrolled study. People with kidney disease, hemochromatosis (iron overload), or those who are pregnant should consult a physician before using shilajit.

Ashwagandha is generally well-tolerated in clinical trials at standard doses. Rare case reports of liver injury have appeared in the broader literature, though causality is uncertain in most instances. Ashwagandha has thyroid-stimulating properties and may interact with thyroid medications or immunosuppressants. People with autoimmune conditions, thyroid disorders, or those who are pregnant should speak with a doctor before use. Neither supplement replaces medical treatment for any diagnosed condition.

A Note on the Evidence

Most clinical trials on both supplements are small, short-term, and sometimes conducted by parties with commercial interests — findings should be interpreted cautiously and not treated as established medical fact. Neither shilajit nor ashwagandha is a substitute for treatment of any diagnosed medical condition; consult a qualified healthcare provider before starting either supplement, especially if you are pregnant, have kidney disease, a thyroid disorder, an autoimmune condition, or take prescription medications.

Frequently Asked Questions

Can I take shilajit and ashwagandha together?

There is no clinical trial evidence directly evaluating their combination, so whether they interact or produce additive effects is unknown. Both are generally used for different primary purposes and at different doses. If you are considering taking both simultaneously, consult a healthcare provider — particularly if you take prescription medications or have any chronic health conditions.

Which is better for testosterone?

Both have been studied in this area with modest results. A placebo-controlled trial found purified shilajit was associated with higher testosterone in healthy men over 90 days ^[2], while a systematic review noted ashwagandha appears among the more studied herbs for testosterone, though with variable effect sizes ^[5]. A separate review cautioned that most testosterone-booster supplements — including botanical ones — produce limited real-world changes in serum testosterone ^[7]. Neither supplement should be relied on as a primary treatment for low testosterone.

Is ashwagandha or shilajit better for stress?

Ashwagandha has the clearer evidence for stress. Randomized controlled trials have found significant reductions in perceived stress and anxiety scores with standardized ashwagandha extracts compared to placebo [PMID 31517876, PMID 37740662]. Shilajit has not been studied in the same rigorous way for psychological stress or cortisol reduction.

Is shilajit safe for women?

There is currently no clinical trial evidence on shilajit specifically in women; most shilajit research has focused on male reproductive health. Ashwagandha, by contrast, has been studied in perimenopausal women and found to reduce climacteric symptoms in a randomized controlled trial ^[6]. Women who are pregnant should avoid shilajit, and all women should consult a healthcare provider before use.

How do the mechanisms of shilajit and ashwagandha differ?

Shilajit’s proposed mechanisms center on fulvic acid — which may support cellular nutrient uptake and mitochondrial function — dibenzo-alpha-pyrones (thought to support mitochondrial electron transfer), and a broad spectrum of trace minerals. Ashwagandha’s withanolides are proposed to modulate the HPA axis, reducing cortisol output under stress. These are distinct proposed mechanisms acting on different physiological systems, which is why the two supplements tend to be studied for different outcomes.

Which supplement has better evidence for physical performance?

Ashwagandha currently has the better-controlled evidence: a randomized controlled trial found improved muscle strength and recovery in resistance-trained adults compared to placebo ^[3]. Shilajit has an open-label pilot study reporting favorable physical performance and biomarker changes over 28 days ^[9], but without a placebo control group those findings carry more uncertainty. Both warrant further investigation in larger controlled trials.

References

1. Biswas TK et al. Clinical evaluation of spermatogenic activity of processed Shilajit in oligospermia. Andrologia (2010). PMID 20078516
2. Pandit S et al. Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers. Andrologia (2016). PMID 26395129
3. Wankhede S et al. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. Journal of the International Society of Sports Nutrition (2015). PMID 26609282
4. Lopresti AL et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study. Medicine (2019). PMID 31517876
5. Smith SJ et al. Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review. Advances in nutrition (Bethesda, Md.) (2021). PMID 33150931
6. Gopal S et al. Effect of an ashwagandha (Withania Somnifera) root extract on climacteric symptoms in women during perimenopause: A randomized, double-blind, placebo-controlled study. The journal of obstetrics and gynaecology research (2021). PMID 34553463
7. Morgado A et al. Do "testosterone boosters" really increase serum total testosterone? A systematic review. International journal of impotence research (2024). PMID 37697053
8. Smith SJ et al. Exploring the efficacy and safety of a novel standardized ashwagandha (Withania somnifera) root extract (Witholytin®) in adults experiencing high stress and fatigue in a randomized, double-blind, placebo-controlled trial. Journal of psychopharmacology (Oxford, England) (2023). PMID 37740662
9. Yadav D et al. Safety and Efficacy of TruBlk™ Shilajit Resin Supplementation on Physical Performance and Blood Biomarkers in Healthy Adults: A 28-Day Open-Label Pilot Study. Cureus (2026). PMID 41613504

These statements have not been evaluated by the Food and Drug Administration. Shilajit is not intended to diagnose, treat, cure, or prevent any disease. Shilajit quality varies widely and raw or adulterated products can contain heavy metals; choose a product with a published third-party heavy-metal test (COA). Content is informational only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.