HomeIngredient Library › Ashwagandha

Adaptogenic Herbs

Ashwagandha

Ayurveda's premier adaptogen for stress and resilience

Evidence Grade: B — Good clinical evidence Adaptogenic Herbs

What is Ashwagandha?

B
Evidence Grade B: Good clinical evidence Our evidence grades reflect the quality, volume, and consistency of human clinical trials for the primary uses of this ingredient.

Ashwagandha (Withania somnifera) is a medicinal herb used for over 3,000 years in Ayurvedic medicine. It is classified as an adaptogen — a substance that helps the body resist physiological and psychological stress. The primary active compounds are withanolides, a class of steroidal lactones concentrated in the root. Modern research has validated several traditional uses, particularly for stress, anxiety, testosterone, and physical performance.

Evidence-Based Benefits of Ashwagandha

Stress & cortisol reduction

A double-blind RCT (n=64) found 300 mg KSM-66 twice daily for 60 days reduced serum cortisol by 27.9% and significantly reduced perceived stress scores versus placebo.

Anxiety relief

Meta-analysis of 5 RCTs showed statistically significant reduction in anxiety and stress. Effect sizes are moderate (SMD −0.69 to −1.06 across studies).

Testosterone & male fertility

High-concentration root extract significantly increased testosterone levels (average +15–40%) and improved sperm count, motility, and morphology in infertile men.

Physical performance

400–600 mg/day improved VO2 max, muscle strength, and recovery in both trained and untrained individuals in multiple RCTs.

Sleep quality

600 mg root extract for 12 weeks improved sleep onset latency, total sleep time, and sleep efficiency in adults with insomnia (p<0.05 vs. placebo).

Cognitive function

300 mg KSM-66 twice daily for 8 weeks improved memory, reaction time, and task performance in a double-blind RCT.

Best Forms of Ashwagandha to Buy

Not all forms of ashwagandha are created equal. Bioavailability — how much the body actually absorbs and uses — varies significantly between forms. Ranked from most to least recommended:

★★★★★
KSM-66 (root extract, 5% withanolides)
Most clinically studied; 600–1200 mg/day used in trials
★★★★☆
Sensoril (root + leaf, 10% withanolides)
Higher withanolide concentration; effective at 250–500 mg/day
★★★★☆
Shoden (35% withanolide glycosides)
Highest potency; 120 mg/day clinically effective
★★☆☆☆
Generic root powder
Inconsistent withanolide content; higher doses needed (3–6 g/day)

Dosage Guide

Standard300–600 mg standardised extract (KSM-66 or Sensoril) daily
Upper LimitNo established UL; studies up to 1,250 mg/day show safety
TimingWith meals to reduce GI discomfort. Can split into morning and evening doses.
NotesEffects build over 4–8 weeks of consistent use. Many users report noticing stress reduction within 2 weeks.

Drug & Supplement Interactions

Always inform your doctor or pharmacist if you are taking ashwagandha alongside prescription medications. Key interactions to be aware of:

High
Thyroid medications (levothyroxine)
Ashwagandha may increase thyroid hormone levels. People on thyroid medications should monitor levels closely.
High
Immunosuppressants
Ashwagandha stimulates immune function, which may counteract immunosuppressive therapy.
Medium
Sedatives/CNS depressants
Additive sedative effects. Use caution with benzodiazepines, sleep medications, or alcohol.
Medium
Diabetes medications
May lower blood glucose. Monitor blood sugar levels; dosage adjustment may be needed.

Signs of Ashwagandha Deficiency

N/A — ashwagandha is not an essential nutrient

Top Food Sources of Ashwagandha

Root and berry of Withania somnifera plant; not commonly found in food

Safety & Side Effects

⚠ Safety Information

Well-tolerated in most people at standard doses. Rare reports of liver injury at very high doses — use reputable standardised extracts. Contraindicated in pregnancy (may stimulate uterine contractions). Not recommended for people with autoimmune conditions (lupus, MS, rheumatoid arthritis) without medical supervision.

This information is for educational purposes only. Always consult a qualified healthcare professional before starting any supplement, especially if you have a medical condition or take medications.

References & Clinical Citations