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.
Every Ashwagandha product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Nootropics Depot Shoden® Ashwagandha Capsules | 95 A | $0.67 |
| 2 | Nootropics Depot Ashwagandha Extract Powder | 93 A | $0.20 |
| 3 | Nootropics Depot Ashwagandha Extract Tablets | 93 A | $0.22 |
| 4 | Nutricost Ashwagandha Root Capsules | 93 A | $0.14 |
| 5 | Transparent Labs KSM-66 Ashwagandha Supplement | 93 A | $0.33 |
| 6 | Jarrow Formulas Ashwagandha | 92 A | $0.21 |
| 7 | Pure Encapsulations Ashwagandha | 92 A | $0.48 |
| 8 | Thorne Thyroid Health Complex | 90 A | $0.33 |
| 9 | Double Wood Ashwagandha Supplement | 90 A | $0.33 |
| 10 | Sports Research Ashwagandha | 89 A | $1.00 |
| 11 | Thorne Memoractiv™ | 89 A | $2.33 |
| 12 | Pure Encapsulations PureLean Satiety | 89 A | $0.88 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Ashwagandha should I take?
The typical range is 300-600 mg daily (KSM-66/Sensoril). Benefits build over weeks
When should I take Ashwagandha?
Evening often best for sleep. Optional.
Which form of Ashwagandha is best?
KSM-66 — Root extract, most studied. Other forms in the catalog: Sensoril, Root powder, Capsule, Powder, Root extract, Capsules, Standardized extract.
Is Ashwagandha safe?
Commonly reported: Drowsiness, GI upset, Headache. Serious warnings: May affect thyroid. Safe
Which Ashwagandha supplement scores highest?
Nootropics Depot Shoden® Ashwagandha Capsules, at 95/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Stress/anxiety
- Cortisol reduction
- Sleep
- Testosterone support
- Strength gains
- Fertility
- Subclinical hypothyroidism
- TSH normalization
- Thyroid support
- Stress and anxiety reduction
- Cortisol management
What systematic reviews concluded
Outcomes that systematic reviews of Ashwagandha reached a verdict on: 13 with a benefit, 2 with no effect, 6 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (13)
“significantly reduced anxiety” PMID 36017529
“Brief-term supplementation with WS appears to have a stress-reducing effect in stressed individuals.” PMID 38140274
“increased muscle strength and recovery” PMID 41906501
“Ashwagandha significantly reduced cortisol (SMD =- 1.18, p < 0.04)” PMID 41740946
“increased serotonin (MD = 31.75 ng/ml, p < 0.01)” PMID 41740946
“Participants supplemented with Ws displayed reduced levels of oxidative stress and inflammation, and counterbalanced hormone levels.” PMID 37428341
and 7 more.
Reviews found no effect (2)
“This treatment did not influence E2 levels in either gender.” PMID 41740946
“No evidence of the beneficial effects of Ws supplementation on hematological markers was reported.” PMID 37428341
Not enough to say: exercise performance; depressive symptoms; sleep quality; cognitive function; thyroid hormones; testosterone.
1 finding from reviews in specific patient groups (such as cancer, pregnancy or surgery) is not shown here.
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
- 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
Related in Nootropic
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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.