Safety of Ashwagandha (Withania somnifera) in Adults
Ashwagandha appears to be generally safe for most adults when used at standard doses for short-term use (up to 8 weeks), though caution is warranted due to limited long-term safety data and potential interactions with medications.
Safety Profile
Ashwagandha has been evaluated in several clinical trials that demonstrate a relatively benign safety profile in healthy adults:
A randomized, double-blind, placebo-controlled study in 80 healthy adults found no significant adverse effects or abnormalities in hematological parameters, biochemistry, or thyroid function after 8 weeks of supplementation with 300 mg twice daily 1.
A comprehensive review of 30 human studies showed reasonable safety with only mild and transient adverse events reported 2.
Common Side Effects
When side effects do occur, they are typically mild and may include:
Most common (>5% of users):
- Somnolence
- Epigastric discomfort
- Loose stools
Less common side effects:
- Drowsiness
- Vertigo
- Nasal congestion
- Decreased appetite
- Dry mouth
- Hyperactivity
- Blurred vision 2
Specific Concerns and Precautions
Sedative Properties
Ashwagandha has sedative properties that may interact with anesthesia medications. The American Journal of Kidney Diseases notes that ashwagandha may enhance the sedative properties of certain anesthetics 3.
Potential for Hallucinogenic Effects
One study reported a participant experiencing increased appetite, libido, and hallucinogenic effects with vertigo even at the lowest dose tested, requiring withdrawal from the study 4.
Drug Interactions
Limited data exists on drug interactions, but caution should be exercised when combining with:
- Sedatives or anxiolytics (potential additive effects)
- Thyroid medications (may affect thyroid hormone levels)
- Immunosuppressants (due to immunomodulatory effects)
Special Populations
Pregnancy and Breastfeeding
Ashwagandha should be avoided in pregnancy due to insufficient safety data and traditional use as an abortifacient in some cultures.
Individuals with Autoimmune Conditions
Due to its immunomodulatory effects, those with autoimmune conditions should use with caution.
Individuals with Thyroid Disorders
Some studies suggest ashwagandha may affect thyroid hormone levels, warranting caution in those with thyroid conditions.
Quality Concerns
As a dietary supplement, ashwagandha is not subject to the same regulatory oversight as prescription medications:
- Purity and potency may vary between products
- Standardization of active compounds is inconsistent
- Contamination with heavy metals or other substances is possible
Duration of Use
Most clinical studies have evaluated ashwagandha for periods of 8-12 weeks. Long-term safety data beyond this timeframe is limited 2.
Conclusion
While short-term use of ashwagandha appears relatively safe for most healthy adults, individuals should:
- Consult healthcare providers before use, especially if taking medications or having pre-existing conditions
- Choose products from reputable manufacturers
- Start with lower doses to assess tolerance
- Be aware of potential side effects
- Avoid long-term use without medical supervision
The safety profile appears favorable based on available evidence, but more rigorous long-term studies are needed to fully establish its safety for extended use.