Ashwagandha
An Ayurvedic adaptogen used for over 3,000 years that has become one of the most popular and well-studied supplements for stress, anxiety, and cognitive function. Ashwagandha (Withania somnifera) significantly reduces cortisol levels, improves stress resilience, and enhances memory and reaction time. KSM-66 and Sensoril are the two most studied standardized extracts.
Ashwagandha (Withania somnifera) has undergone a remarkable transition from ancient Ayurvedic remedy to one of the most clinically validated adaptogenic supplements available. The name comes from Sanskrit meaning 'smell of the horse,' referring both to the root's distinctive odor and the traditional belief that it gives the consumer horse-like vitality and strength.
The two most studied standardized extracts are KSM-66 (full-spectrum root extract standardized to 5% withanolides) and Sensoril (root and leaf extract standardized to 10% withanolides). KSM-66 has the most clinical trials specifically for cognitive function and stress reduction, while Sensoril tends to be more sedating and is often preferred for anxiety and sleep. The choice between them depends on whether you want an energizing adaptogen (KSM-66) or a calming one (Sensoril).
The cortisol reduction is ashwagandha's headline effect — clinical trials consistently show 25-30% reductions in serum cortisol levels in chronically stressed individuals. Since elevated cortisol impairs hippocampal function (memory), prefrontal cortex activity (executive function), and sleep quality, reducing it has cascading cognitive benefits. However, ashwagandha should be used with caution by anyone with thyroid conditions, as it can elevate T3 and T4 levels.
Dosage
KSM-66 extract: 300-600 mg daily. Sensoril extract: 125-250 mg daily. Root powder: 3-6 g daily. Best taken with food. Can be taken morning or evening (does not cause drowsiness in most people).
Dosages shown are for research reference only. Always consult a qualified healthcare provider.
Half-Life
6-12 hours (withanolides)
Administration
Oral (capsules, powder). Standardized extracts (KSM-66 or Sensoril) are preferred over raw root powder for consistent dosing.
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Mechanism of Action
Ashwagandha's withanolide compounds (withaferin A, withanolide A, withanone) modulate the hypothalamic-pituitary-adrenal (HPA) axis, reducing corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) signaling, thereby lowering cortisol production by 25-30% in stressed individuals. It acts as a GABA-A receptor positive allosteric modulator at the benzodiazepine site, producing anxiolytic effects without sedation. Ashwagandha inhibits acetylcholinesterase (AChE), raising acetylcholine levels in the hippocampus and cortex. The withanolides have anti-inflammatory properties via inhibition of NF-κB and COX-2, and antioxidant effects that reduce neuroinflammation and oxidative stress. It may support neurogenesis through upregulation of BDNF and its receptor TrkB, and modulation of the PI3K/Akt pathway.
Regulatory Status
Dietary supplement worldwide. Used as a traditional medicine in India. Not FDA-approved for any medical condition. GRAS ingredient.
Risks & Safety
Common
Gastrointestinal discomfort, drowsiness at higher doses, thyroid hormone elevation.
Serious
Can cause hyperthyroidism in susceptible individuals — avoid with thyroid conditions without medical oversight. Rare liver injury reports.
Rare
Vertigo, nasal congestion, sexual dysfunction.
Compare Ashwagandha With
Research Papers
9Published: November 24, 2022
AI Summary
We found that Ashwagandha supplementation significantly reduced anxiety (SMD: -1.55, 95% CI: -2.37, -0.74; p = .005; I2  = 93.8%) and stress level (SMD: -1.75; 95% CI: -2.29, -1.22; p = .005; I2  = 83.1%) compared to the placebo.
Published: November 19, 2023
AI Summary
The main mechanism of action in the latter appears to be based on the hypothalamus-pituitary-adrenal (HPA) axis, as a decrease in cortisol levels and an increase in hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in men were found, which results in stress level reduction and improvement in fertility.
Published: September 23, 2021
AI Summary
To determine the effect of Ashwagandha extract on sleep.
Published: April 2, 2021
AI Summary
W. somnifera has demonstrated various biological actions such as anti-cancer, anti-inflammatory, anti-diabetic, anti-microbial, anti-arthritic, anti-stress/adaptogenic, neuro-protective, cardio-protective, hepato-protective, immunomodulatory properties. Furthermore, W.
Published: August 1, 2024
AI Summary
Despite the numerous benefits of ashwagandha supplementation, there have been just four meta-analyses on the herb's effectiveness in treating anxiety, neurobehavioral disorders, impotence, and infertility. Moreover, no reviews exist that examine how ashwagandha affects antioxidant response and physical sports performance.
Published: September 30, 2023
AI Summary
Ashwagandha herb is commonly used in Ayurveda and a "fad" dietary supplement for a host of indications based on low levels of evidence. Recently, ashwagandha was implicated in multiple reports of herb-induced liver injury (HILI), mainly from the United States.
Published: September 20, 2024
AI Summary
Ashwagandha (Withania somnifera) is an adaptogenic herb used to prevent and treat psychosomatic disorders. This systematic review and meta-analysis evaluated the effects and safety of Ashwagandha on psychosomatic functions related to stress and anxiety among patients.
Published: March 23, 2023
AI Summary
Its current research covers many aspects of human health, including neuroprotective, sedative and adaptogenic effects and effects on sleep. This narrative review delves into the most recent findings and provides a comprehensive overview of the current understanding of ashwagandha's potential uses and any known safety concerns and contraindications.
Published: March 29, 2021
AI Summary
WS has seen an increase in worldwide usage due to its reputation as an adaptogen. This popularity has elicited increased scientific study of its biological effects, including a potential application for neuropsychiatric and neurodegenerative disorders.
Frequently Asked Questions
What is Ashwagandha used for?
An Ayurvedic adaptogen used for over 3,000 years that has become one of the most popular and well-studied supplements for stress, anxiety, and cognitive function. Ashwagandha (Withania somnifera) significantly reduces cortisol levels, improves stress resilience, and enhances memory and reaction time. KSM-66 and Sensoril are the two most studied standardized extracts.
What are the side effects of Ashwagandha?
Common: Gastrointestinal discomfort, drowsiness at higher doses, thyroid hormone elevation. Serious: Can cause hyperthyroidism in susceptible individuals — avoid with thyroid conditions without medical oversight. Rare liver injury reports. Rare: Vertigo, nasal congestion, sexual dysfunction.
How is Ashwagandha administered?
Ashwagandha is administered via oral (capsules, powder). standardized extracts (ksm-66 or sensoril) are preferred over raw root powder for consistent dosing..
What is the half-life of Ashwagandha?
The half-life of Ashwagandha is 6-12 hours (withanolides).
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