Nootropic
Ashwagandha
Also known as: Withania somnifera, Indian ginseng, Ashwagandha (Thyroid Support), Ashwagandha Extract (Withania somnifera)
Ashwagandha is a traditional Ayurvedic herb standardized for withanolides, with evidence supporting modest benefits for stress reduction, anxiety, and cortisol modulation. Multiple clinical trials demonstrate efficacy for stress-related symptoms, though effect sizes are generally moderate.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Primary uses
- Stress/anxiety
- Cortisol reduction
- Sleep
- Testosterone support
- Strength gains
- Fertility
- Subclinical hypothyroidism
- TSH normalization
- Thyroid support
- Stress and anxiety reduction
- Cortisol management
- Sleep quality support
How it works
- GABAergic activity
- Cortisol reduction
- Thyroid hormone support
Dosage
- Typical range
- 300-600 mg daily (KSM-66/Sensoril)
- Timing
- Evening often best for sleep
- With food
- Optional
- Duration
- Benefits build over weeks
- Special populations
- Anxiety, stress, low testosterone
Forms
- KSM-66
- Sensoril
- Root powder
- Capsule
- Powder
- Root extract
- Capsules
- Standardized extract· 70/100
Safety
Common side effects
- Drowsiness
- GI upset
- Headache
Contraindications
- Hyperthyroidism
- Nightshade sensitivity
Products containing Ashwagandha
Top-scoring supplements in our catalog that list Ashwagandha on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Known interactions
- Warningwith thyroid medication
Ashwagandha can raise thyroid hormone levels and stack additively with levothyroxine, risking thyrotoxicosis.
- Warningwith sedatives
May enhance sedative effects
- Synergywith black pepper
Piperine may enhance ashwagandha absorption
- Cautionwith ssri
Ashwagandha may enhance SSRI effects
Evidence notes
Best-studied adaptogen for anxiety
Grade A: Multiple well-designed human trials support the main claims.
Cited research for Ashwagandha
Clinical studies referenced across Formulate guides that mention ashwagandha. Each links to the full study page with PubMed source + the guides that cite it.
- Primary literature (2026)Monograph
Memorial Sloan Kettering Integrative Medicine Monograph: Ashwagandha
- Primary literature (2022)Case report
Ashwagandha as a Unique Cause of Thyrotoxicosis Presenting with Supraventricular Tachycardia
- Lopresti et al. (2019)Medicine
An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract
- Salve J, Pate S, Debnath K, Langade D (2019)Cureus
An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract
- Sharma et al. (2018)J Altern Complement Med
Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial
- Wankhede et al. (2015)Journal of the International Society of Sports Nutrition
Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial
- Pratte et al. (2014)Journal of Alternative and Complementary Medicine
An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha
- Gannon et al. (2014)J Ayurveda Integr Med
Subtle changes in thyroid indices during a placebo-controlled study of an extract of Withania somnifera in persons with bipolar disorder
Ashwagandha compared head-to-head
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.