What are the benefits and risks of using ashwagandha (Withania somnifera) in adults with a history of medical conditions or those taking medications, such as blood thinners, diabetes medications, or thyroid medications?

Ashwagandha: Benefits and Risks

Ashwagandha (Withania somnifera) shows modest evidence for reducing stress and anxiety in adults, but lacks FDA approval and standardized quality control in the United States, making it impossible to recommend with confidence for any medical condition, particularly in patients taking medications or with underlying health conditions.

Evidence for Potential Benefits

Stress and Anxiety Reduction

• Randomized controlled trials demonstrate that ashwagandha extract (240-300 mg daily) significantly reduces stress assessment scores and anxiety symptoms compared to placebo over 60 days 1, 2
• The mechanism appears to involve modulation of the hypothalamus-pituitary-adrenal axis, with significant reductions in morning cortisol levels (P < 0.001) 2
• Effects on anxiety are modest, with statistically significant reductions on the Hamilton Anxiety Rating Scale but only near-significant changes on other validated scales 2

Sleep Quality

• Limited evidence suggests ashwagandha may improve sleep quality in some populations, though the data quality is insufficient for firm recommendations 3, 4

Cognitive Function

• Small studies in heterogeneous populations (including older adults with mild cognitive impairment and patients with psychiatric disorders) show improvements in executive function, attention, and reaction time 5
• The clinical significance of these cognitive improvements remains uncertain given the limited sample sizes and diverse populations studied 5

Critical Safety Concerns and Drug Interactions

Lack of FDA Regulation

• Ashwagandha is not FDA-approved or regulated in the United States, meaning no quality control standards exist for contents or potency 6
• Patients cannot reliably obtain preparations with similar effectiveness or safety profiles as those used in research studies 6

Cytochrome P450 Interactions

• Ashwagandha may inhibit multiple cytochrome P450 enzymes (similar to other herbal supplements), potentially reducing bioavailability or efficacy of medications metabolized through these pathways 6, 7
• This creates particular concern for patients taking blood thinners, diabetes medications, thyroid medications, oral contraceptives, or immunosuppressants 6

Thyroid Hormone Effects

• Preclinical studies report increases in thyroxine (T4) levels with ashwagandha root 4
• Patients taking thyroid medications require close monitoring if using ashwagandha, as it may alter thyroid hormone levels unpredictably 4

Perioperative Risks

• Ashwagandha should be discontinued at least 2 weeks before surgery due to potential central nervous system depression effects 7

Comparison to Evidence-Based Alternatives

For Anxiety and Stress

• First-line treatment should be evidence-based psychotherapy (cognitive behavioral therapy) or FDA-approved medications with established safety profiles 7
• Unlike ashwagandha, second-generation antidepressants have moderate-quality evidence for efficacy, standardized dosing, and known safety profiles 6

For Insomnia

• Cognitive Behavioral Therapy for Insomnia (CBT-I) is the gold standard first-line treatment with superior long-term efficacy compared to any supplement 8
• Ashwagandha lacks proven efficacy for chronic insomnia disorder compared to placebo 7

Common Adverse Effects

• Mild and transient adverse events reported in clinical trials include somnolence, epigastric pain/discomfort, loose stools, giddiness, drowsiness, and dry mouth 4
• No serious adverse events were reported in the 30 human trials reviewed, though long-term safety data beyond 8 months are lacking 4

Clinical Decision Algorithm

For patients considering ashwagandha:

1. Screen for contraindications: Patients taking medications metabolized by cytochrome P450 enzymes, thyroid medications, blood thinners, diabetes medications, or planning surgery within 2 weeks should avoid ashwagandha 6, 7, 4

2. Prioritize evidence-based treatments: Direct patients with anxiety, stress, or insomnia to cognitive behavioral therapy or FDA-approved medications as first-line options 6, 8, 7

3. If patient insists on ashwagandha despite counseling: Warn about lack of quality control, unknown drug interactions, and modest evidence base 6, 3

4. Monitor closely: Check for adverse effects, medication interactions, and thyroid function if applicable 4

Common Pitfalls to Avoid

• Assuming herbal supplements are safe because they are "natural"—ashwagandha has significant drug interaction potential and lacks quality control 6, 7
• Failing to counsel patients about superior evidence-based alternatives before they invest time and money in unregulated supplements 8, 7
• Not screening for cytochrome P450-metabolized medications that could interact dangerously with ashwagandha 6, 7
• Overlooking thyroid medication interactions in patients with hypothyroidism or hyperthyroidism 4