Ashwagandha

• Stress reduction
• Cortisol regulation
• Neuroprotection
• Immune modulation

• Thyroid support
• Cognitive enhancement
• Sleep improvement
• Muscle strength and recovery
• Testosterone support
• Fertility enhancement
• Blood sugar regulation
• Inflammation reduction
• Anxiety relief

Ashwagandha (Withania somnifera) exerts its diverse biological effects through multiple mechanisms involving various bioactive compounds, with withanolides being the primary active constituents. These steroidal lactones, particularly withaferin A and withanolide A, contribute to ashwagandha’s adaptogenic, anti-inflammatory, immunomodulatory, and neuroprotective properties. One of ashwagandha’s primary mechanisms is modulation of the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body’s stress response. Ashwagandha appears to reduce cortisol levels by dampening the stress-induced activation of the HPA axis.

This cortisol-lowering effect has been demonstrated in multiple human clinical trials and may explain many of ashwagandha’s stress-reducing and adaptogenic properties. By helping regulate cortisol, ashwagandha may indirectly influence numerous physiological processes affected by chronic stress, including immune function, metabolism, and reproductive health. In the central nervous system, ashwagandha exhibits GABAergic activity, mimicking the effects of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). By enhancing GABA signaling, ashwagandha produces anxiolytic (anxiety-reducing) effects without causing sedation at typical doses.

This GABAergic activity may contribute to ashwagandha’s benefits for anxiety, stress, and sleep quality. Additionally, ashwagandha demonstrates neuroprotective properties through multiple mechanisms. It increases levels of antioxidant enzymes in the brain, including superoxide dismutase (SOD), catalase, and glutathione peroxidase, helping protect neurons from oxidative damage. Withanolides also promote dendrite formation and synaptic reconstruction, potentially enhancing cognitive function and supporting neuronal health.

Some research suggests ashwagandha may inhibit acetylcholinesterase (the enzyme that breaks down acetylcholine), thereby increasing acetylcholine levels and potentially improving memory and cognitive function. Ashwagandha also appears to influence neurotransmitter systems beyond GABA, including serotonin, dopamine, and glutamate, which may contribute to its effects on mood, cognition, and stress resilience. In the immune system, ashwagandha exhibits immunomodulatory effects, enhancing the activity of natural killer cells, increasing CD4+ T cell counts, and modulating cytokine production. Rather than simply stimulating or suppressing immune function, ashwagandha appears to normalize immune responses, enhancing activity when needed while preventing excessive inflammation.

This balanced immunomodulation may be particularly beneficial for conditions involving immune dysregulation. Ashwagandha’s anti-inflammatory properties are mediated through several pathways. Withanolides, particularly withaferin A, inhibit nuclear factor-kappa B (NF-κB) activation, a key transcription factor in inflammatory responses. This inhibition reduces the production of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6).

Additionally, ashwagandha inhibits cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), further reducing inflammatory mediator production. For hormonal effects, ashwagandha appears to support thyroid function by increasing serum levels of T3 and T4 in some studies, potentially through direct effects on the thyroid gland or via modulation of the HPA axis. In men, ashwagandha has been shown to increase testosterone levels and improve semen parameters, likely through multiple mechanisms including stress reduction, antioxidant effects, and possibly direct effects on the hypothalamic-pituitary-gonadal axis. In the cardiovascular system, ashwagandha demonstrates cardioprotective effects through antioxidant activity, reduction of lipid peroxidation, and improvement in lipid profiles.

It may also help regulate blood pressure through effects on vascular tone and stress reduction. For metabolic health, ashwagandha appears to improve insulin sensitivity and reduce blood glucose levels through several mechanisms, including enhanced insulin secretion, improved insulin receptor sensitivity, and increased glucose uptake in muscle cells. These effects may be partially mediated through stress reduction, as chronic stress and elevated cortisol can contribute to insulin resistance. At the cellular level, ashwagandha exhibits significant antioxidant properties, both through direct free radical scavenging and by enhancing endogenous antioxidant systems.

This antioxidant activity may contribute to many of ashwagandha’s protective effects across various organ systems. Additionally, some research suggests ashwagandha may have anti-cancer properties through multiple mechanisms, including induction of apoptosis, cell cycle arrest, and inhibition of angiogenesis, though these effects have primarily been observed in preclinical studies. Through these diverse and complementary mechanisms, ashwagandha influences numerous physiological processes, explaining its wide range of traditional uses and the growing body of scientific evidence supporting its various health benefits.

Ashwagandha dosing varies based on the form used, the standardization of active compounds (particularly withanolides), and the specific health goal. No official Recommended Dietary Allowance (RDA) exists for ashwagandha as it is not an essential nutrient. For root powder (non-standardized), traditional Ayurvedic dosing typically ranges from 3-6 grams daily. For standardized root extracts (typically containing 2.5-5% withanolides), the most commonly studied effective dose range is 300-600 mg per day.

Higher potency extracts with greater withanolide concentrations (such as Shoden® at 35% withanolides) may be effective at lower doses, typically 120-240 mg daily. Most clinical studies showing benefits have used daily dosing for 8-12 weeks, though some traditional uses involve longer-term administration. Ashwagandha is often taken in divided doses (typically twice daily) to maintain more consistent blood levels, though single daily dosing has also shown efficacy in studies.

The bioavailability of ashwagandha’s active compounds, particularly withanolides, is relatively low when consumed orally. Withanolides are poorly water-soluble and subject to significant first-pass metabolism in the liver, which limits their systemic availability. Precise absorption rates for specific withanolides in humans are not well-established, but pharmacokinetic studies suggest that withaferin A, one of the key bioactive compounds, has an oral bioavailability of approximately 20-30% in animal models. Absorption occurs primarily in the small intestine, with some compounds potentially being metabolized by gut microbiota before absorption.

After absorption, withanolides are distributed throughout the body, with some evidence suggesting they can cross the blood-brain barrier, explaining ashwagandha’s neurological effects. The plasma half-life of various withanolides ranges from approximately 1.5-7 hours, depending on the specific compound. Despite this relatively short half-life, the biological effects of ashwagandha often persist longer, suggesting that its compounds may induce longer-lasting changes in gene expression, enzyme activity, or cellular function. Metabolism occurs primarily in the liver through phase I and phase II biotransformation, with metabolites being excreted mainly through urine and to a lesser extent through bile.

Taking with a meal containing fat may enhance absorption of fat-soluble withanolides, Black pepper extract (piperine) can increase bioavailability by inhibiting enzymes involved in drug metabolism and preventing intestinal efflux, Liposomal formulations may improve absorption by enhancing solubility and intestinal uptake, Full-spectrum extracts containing multiple withanolides may provide synergistic effects compared to isolated compounds, Standardized extracts with higher withanolide content provide more consistent and potent effects, Fermented preparations may enhance bioavailability through partial breakdown of plant cell walls and conversion to more bioavailable metabolites, Traditional Ayurvedic preparation with ghee (clarified butter) may enhance absorption of fat-soluble compounds, Micronized powder forms with smaller particle size may improve dissolution and absorption, Consuming with warm water or warm milk (traditional method) may enhance solubility and absorption, Patented extraction processes (as in KSM-66®, Sensoril®, or Shoden®) may enhance bioavailability through proprietary methods

For general adaptogenic effects and stress reduction, ashwagandha can be taken once or twice daily, with or without food. Many practitioners recommend dividing the daily dose into morning and evening administrations to maintain more consistent blood levels of active compounds. When using ashwagandha primarily for stress and anxiety reduction, taking a dose in the morning may help manage daytime stress, while an evening dose may support relaxation and sleep quality. For those who experience mild stimulation from ashwagandha (which occurs in some individuals), morning or early afternoon dosing is preferable to avoid potential sleep disruption.

Conversely, those who experience a calming effect may benefit from evening dosing. When using ashwagandha specifically for sleep improvement, taking the full daily dose or a larger portion of the divided dose approximately 1-2 hours before bedtime may be most effective. This timing allows the active compounds to reach peak blood levels around the time of sleep onset. For athletic performance and recovery, some research suggests taking ashwagandha approximately 1 hour before exercise may enhance performance, while daily consistent use appears more important for long-term adaptations and recovery benefits.

When using ashwagandha for thyroid support, morning administration may theoretically align better with the body’s natural circadian rhythm of thyroid hormone production, though research specifically examining timing effects is limited. For blood sugar management, taking ashwagandha before meals may theoretically provide better effects on postprandial glucose levels, though consistent daily use appears more important than specific timing for this application. Consistency in daily supplementation is generally more important than specific timing for many of ashwagandha’s benefits, particularly for adaptogenic effects that develop through cumulative action over time. Traditional Ayurvedic texts often recommend taking ashwagandha with warm milk or water, sometimes with the addition of honey or ghee (clarified butter).

This traditional method may enhance absorption and palatability, particularly for the root powder form which has a characteristic bitter taste.

• Generally well-tolerated with minimal reported side effects at recommended doses
• Mild gastrointestinal discomfort (nausea, upset stomach, diarrhea)
• Drowsiness or sedation (more common at higher doses)
• Headache (uncommon)
• Dry mouth
• Increased appetite in some individuals
• Potential for mild stimulation in some individuals (paradoxical reaction)
• Possible allergic reactions in sensitive individuals
• Unpleasant taste (primarily with root powder forms)
• Potential for mild increases in thyroid hormone levels (may be beneficial in hypothyroidism but problematic in hyperthyroidism)

• Pregnancy and breastfeeding (insufficient safety data; traditionally considered a uterine tonic but modern caution advised)
• Autoimmune conditions (theoretical concern due to immune-stimulating properties)
• Hyperthyroidism (may further increase thyroid hormone levels)
• Hemochromatosis (iron overload condition; ashwagandha may increase iron absorption)
• Hormone-sensitive cancers (theoretical concern due to potential mild estrogenic effects)
• Upcoming surgery (discontinue 2-3 weeks before due to potential mild anticoagulant effects)
• Diabetes (may lower blood sugar, requiring medication adjustment)
• Peptic ulcers (may increase stomach acid production)
• Known allergy to plants in the Solanaceae (nightshade) family
• Severe liver or kidney disease (insufficient safety data)

• Sedatives and CNS depressants (potential additive effects)
• Thyroid medications (may alter thyroid hormone levels, requiring dose adjustment)
• Immunosuppressants (theoretical interaction due to immune-modulating effects)
• Antidiabetic medications (may enhance blood glucose-lowering effects)
• Antihypertensive medications (may enhance blood pressure-lowering effects)
• Anticoagulants and antiplatelet drugs (theoretical mild additive effect on bleeding risk)
• Benzodiazepines (potential additive effects due to GABA-ergic activity)
• Barbiturates (potential additive sedative effects)
• Medications metabolized by cytochrome P450 enzymes (theoretical interaction)
• Alcohol (potential additive sedative effects)

No official Tolerable Upper Intake Level (UL) has been established for ashwagandha. Based on available research, doses up to 1,000 mg of root extract (standardized to 2.5-5% withanolides) per day appear to be well-tolerated by most healthy adults for periods of up to 12 weeks. Traditional Ayurvedic medicine sometimes uses higher doses of the root powder (up to 6-10 grams daily), but these higher doses may increase the risk of side effects, particularly gastrointestinal discomfort. Long-term safety data beyond 12 weeks is limited in modern clinical trials, though traditional use suggests safety with extended use at appropriate doses.

As with any supplement, it’s prudent to use the lowest effective dose for the intended purpose, particularly for long-term use. Those with pre-existing health conditions, on medications, or with specific sensitivities should consult healthcare providers before using ashwagandha. A note on liver effects: While generally considered hepatoprotective in traditional use and most research, rare cases of liver injury have been reported with ashwagandha supplements. These cases are extremely uncommon and may be related to product quality issues (contamination, adulteration) rather than ashwagandha itself.

However, individuals with pre-existing liver conditions should exercise caution and consult healthcare providers before use.

In the United States, ashwagandha is regulated as a dietary supplement under the Dietary Supplement Health and Education Act (DSHEA) of 1994. Under DSHEA, manufacturers are responsible for determining that their products are safe before marketing, but do not need FDA approval. The FDA has not approved specific health claims for ashwagandha supplements. Manufacturers must limit their claims to structure/function statements (how the product affects the structure or function of the body) rather than disease claims (preventing, treating, or curing specific diseases).

Ashwagandha is included in the FDA’s Generally Recognized as Safe (GRAS) database for certain food uses, though this applies to specific applications rather than all uses. The FDA does not routinely test dietary supplements for safety or efficacy before they reach the market, but can take action against unsafe products or those making illegal disease claims. In 2021, the FDA issued warning letters to several companies marketing ashwagandha products with claims related to treating COVID-19, highlighting the regulatory limitations on disease claims for this herb.

Eu: In the European Union, ashwagandha is regulated under the Traditional Herbal Medicinal Products Directive (THMPD) in some member states, allowing traditional use registrations based on historical use rather than clinical trials. In other contexts, it may be regulated as a food supplement under the Food Supplements Directive (2002/46/EC). The European Food Safety Authority (EFSA) has not approved specific health claims for ashwagandha under the Nutrition and Health Claims Regulation. Regulatory status varies somewhat between EU member states, with some countries having more permissive regulations for traditional herbal products than others.

India: In India, ashwagandha is recognized in the Ayurvedic Pharmacopoeia of India and is regulated as an Ayurvedic medicine under the Drugs and Cosmetics Act. It can be legally marketed with specific Ayurvedic indications and is included in numerous licensed Ayurvedic formulations. The Ministry of AYUSH (Ayurveda, Yoga & Naturopathy, Unani, Siddha, and Homeopathy) provides specific guidelines for the quality and manufacturing of ashwagandha products.

Canada: Health Canada has approved ashwagandha as a Natural Health Product (NHP) ingredient with authorized claims related to its role as an adaptogen and for use in Ayurvedic medicine. Ashwagandha products with approved Natural Product Numbers (NPNs) can be legally sold in Canada with specific authorized claims. Health Canada has established specific quality requirements and dosage recommendations for ashwagandha products.

Australia: The Australian Therapeutic Goods Administration (TGA) regulates ashwagandha as a listed complementary medicine ingredient. Ashwagandha products can be listed on the Australian Register of Therapeutic Goods (ARTG) after meeting safety, quality, and efficacy requirements. The TGA has specific guidelines regarding permitted indications for listed complementary medicines containing ashwagandha.

Japan: In Japan, ashwagandha may be regulated as a non-pharmaceutical health food or as an ingredient in Foods with Function Claims (FFC), depending on the specific product and claims. It is not typically approved as a Kampo medicine (traditional Japanese herbal medicine) as it is not part of the traditional Japanese pharmacopoeia.

Low to moderate

$0.10-$0.30 per day for basic root powder; $0.30-$0.80 per day for standardized extracts; $0.50-$1.50 per day for premium branded extracts (KSM-66®, Sensoril®, Shoden®)

Ashwagandha offers excellent value compared to many other supplements, providing multiple evidence-based benefits at a relatively modest cost. Basic ashwagandha root powder is the most economical option, typically costing $0.10-$0.30 per effective daily dose (3-6 grams). While inexpensive, the root powder has a strong taste that many find unpleasant, and its withanolide content can vary significantly between batches, potentially affecting consistency of results. Standardized extracts offer better consistency and convenience at a moderate price point ($0.30-$0.80 per day for typical 300-600 mg doses).

These products specify the withanolide percentage (typically 2.5-5%), providing more reliable potency than basic root powder. The higher cost is often justified by the improved consistency, convenience, and reduced volume needed. Premium branded extracts like KSM-66®, Sensoril®, and Shoden® command higher prices ($0.50-$1.50 per day) but offer several potential advantages. These products have been used in clinical research, providing greater assurance that the effects will match those reported in studies.

They often use proprietary extraction methods that may preserve a more complete spectrum of beneficial compounds or achieve higher standardization levels. For stress and anxiety reduction, ashwagandha’s cost-effectiveness is particularly notable when compared to many other interventions. At approximately $0.30-$0.80 per day for a standardized extract, ashwagandha is among the most affordable evidence-based options for stress management, with multiple clinical trials supporting its efficacy. For athletic performance and recovery, ashwagandha extracts (typically $0.50-$1.00 per day) compare favorably to many sports supplements, offering benefits for strength, endurance, and recovery at a fraction of the cost of many pre-workout formulas and protein supplements.

When comparing products, calculate the cost per standardized dose rather than per capsule, as potency varies widely between brands. For standardized extracts, divide the price by the total withanolide content rather than just the ashwagandha amount, as this better reflects potency. For those seeking to maximize value, buying in bulk (particularly for root powder) typically offers significant savings over smaller packages. However, given ashwagandha’s relatively low cost even in premium forms, many users find that the convenience and consistency of standardized extracts or branded ingredients justify their moderate price premium over basic root powder.

For specific therapeutic applications, such as significant stress reduction or sleep improvement, the value should also consider potential cost savings from reduced need for other interventions. For example, effective stress management might reduce expenses related to stress-induced health issues or other stress-reduction approaches.

Ashwagandha extracts and powders generally have good stability when properly stored, though this can vary based on the specific preparation method and storage conditions. Dried ashwagandha root powder typically maintains its potency for 1-2 years when stored properly. Standardized extracts in capsule or tablet form generally have a manufacturer-assigned shelf life of 2-3 years, though this is often conservative and the actual stability may be longer. The stability is primarily limited by the potential degradation of withanolides and other bioactive compounds through oxidation and exposure to heat, light, and moisture.

Liquid extracts and tinctures typically have shorter shelf lives (1-2 years) compared to dry forms, particularly after opening. Some manufacturers add natural preservatives like rosemary extract or vitamin E to enhance stability of certain preparations. Properly standardized and packaged commercial products typically include stability testing to ensure the labeled withanolide content remains within acceptable ranges throughout the stated shelf life.

Store in a cool, dry place away from direct light and heat (below 25°C/77°F). Keep containers tightly closed to prevent moisture absorption, as moisture can accelerate degradation of active compounds and potentially promote microbial growth. While refrigeration is not necessary for most ashwagandha products, it may extend shelf life, particularly for liquid extracts after opening. Avoid storing in bathrooms or other high-humidity areas.

For ashwagandha root powder, using the included scoop or a clean, dry utensil is recommended to prevent introducing moisture into the container. Some manufacturers include desiccant packets in ashwagandha containers to maintain dryness – these should be left in place but not consumed. Once opened, ashwagandha powder should ideally be used within 6-12 months for optimal potency, though it may remain stable longer if properly stored. For capsules and tablets, storage in the original container is recommended as these are designed to protect from light and moisture.

Liquid extracts and tinctures should be tightly sealed after use and may benefit from refrigeration after opening. Traditional Ayurvedic preparations like ashwagandha ghee require refrigeration and typically have shorter shelf lives (3-6 months).

Heat (accelerates degradation of withanolides and other bioactive compounds), Light exposure (particularly UV light, can cause photodegradation of active compounds), Moisture (promotes hydrolysis of active compounds and potential microbial growth), Oxygen exposure (leads to oxidation of withanolides and other compounds), Microbial contamination (if moisture is introduced), Enzymatic degradation (particularly in improperly dried or processed material), Extreme pH conditions (can accelerate degradation in liquid formulations), Prolonged exposure to very high humidity, Interaction with certain container materials (particularly some plastics and metals)

Synthesis Methods

Natural Sources

Quality Considerations

Ashwagandha (Withania somnifera) has a rich history spanning over 3,000 years, with its use deeply rooted in Ayurveda, the traditional system of medicine in India. The name ‘ashwagandha’ is derived from Sanskrit, where ‘ashva’ means horse and ‘gandha’ means smell, referring to the herb’s distinctive horse-like odor and the traditional belief that consuming it would impart the strength and vitality of a horse. In classical Ayurvedic texts such as the Charaka Samhita and Sushruta Samhita (dating back to approximately 1000-500 BCE), ashwagandha is classified as a ‘Rasayana’ herb, a category of medicinal plants believed to promote longevity, vitality, and overall well-being. It is particularly emphasized in the branch of Ayurveda focused on rejuvenation and healthy aging.

Ashwagandha is traditionally considered a ‘Vata’ and ‘Kapha’ balancing herb in Ayurvedic medicine, meaning it helps balance these two doshas (constitutional types or bioenergetic forces) while potentially increasing ‘Pitta’ dosha if used in excess. This classification guided its traditional applications for conditions believed to arise from Vata or Kapha imbalances. In traditional Ayurvedic practice, ashwagandha was commonly prepared as a fine powder mixed with warm milk, ghee (clarified butter), or honey to enhance its palatability and efficacy. This preparation, often taken before bed, was believed to promote restful sleep, nourish tissues, and build strength over time.

Another traditional preparation method involved creating medicated ghee (ashwagandha ghrita) or medicated oil (ashwagandha taila) for both internal consumption and external application. Beyond India, ashwagandha has been used in traditional medicine systems in parts of Africa, the Middle East, and other regions where the plant naturally grows or was introduced. In Unani medicine (a traditional system practiced in Middle Eastern and South Asian countries), ashwagandha is known as ‘asgand’ and used for similar purposes as in Ayurveda. Traditional uses of ashwagandha encompass a wide range of applications.

It was commonly prescribed for general debility and weakness, particularly during convalescence after illness. It was considered especially valuable for the elderly to counteract the degenerative effects of aging. Ashwagandha was traditionally used to enhance male reproductive health and vitality, earning it a reputation as a ‘vajikaran’ or aphrodisiac herb in Ayurveda. For women, it was used to support reproductive health, regulate menstruation, and provide strength during pregnancy and postpartum recovery (though modern caution is advised regarding pregnancy use).

The herb was traditionally employed to calm the mind, reduce anxiety, and promote sleep, aligning with its modern classification as an adaptogen. It was also used for joint pain, inflammation, and various types of arthritis, often applied externally as a paste or medicated oil in addition to internal use. Respiratory conditions, including coughs and asthma, were traditionally treated with ashwagandha preparations. The herb was also used for skin conditions, applied both internally and externally.

In the modern era, scientific research beginning in the mid-20th century has validated many of these traditional uses, identifying the withanolides and other compounds responsible for ashwagandha’s diverse effects. The herb gained popularity in Western herbal medicine and natural health communities starting in the 1970s and 1980s, with significant growth in commercial availability and research interest occurring from the 1990s onward. Today, ashwagandha is one of the most popular adaptogenic herbs globally, with its use extending far beyond its traditional Ayurvedic applications. Modern standardized extracts with specific withanolide concentrations have largely replaced traditional preparations in commercial products, though traditional methods of preparation are still used in authentic Ayurvedic practice and by some herbalists.

Ashwagandha for cognitive enhancement in mild cognitive impairment, Effects of ashwagandha on stress resilience and HPA axis function, Ashwagandha for menopausal symptoms and quality of life, Combination of ashwagandha with other adaptogens for stress management, Ashwagandha for athletic performance and recovery in female athletes, Effects of ashwagandha on reproductive hormones in women with PCOS, Ashwagandha for sleep quality improvement in older adults, Comparison of different ashwagandha extracts and standardization methods, Long-term safety and efficacy of ashwagandha supplementation, Ashwagandha’s effects on gut microbiome composition and function