Can one overdose on ashwagandha (Withania somnifera) or L-theanine?

Can You Overdose on Ashwagandha or L-Theanine?

Ashwagandha and L-theanine have extremely low overdose potential compared to conventional pharmaceuticals, with no reported fatal overdoses in humans, though ashwagandha can cause adverse effects at high doses and L-theanine data remains limited.

Ashwagandha Overdose Potential

Safety Profile and Dosing Limits

• The No Observed Adverse Effect Level (NOAEL) for ashwagandha root extract is 2000 mg/kg body weight/day in animal studies, which translates to an extraordinarily high dose in humans 1
• Human studies using doses up to 1250 mg/day for 30 days showed good tolerability with minimal adverse events 2
• An 8-week human safety trial using 600 mg/day (300 mg twice daily) demonstrated no significant adverse effects on hematological, biochemical, hepatic, or thyroid function parameters 3

Documented Adverse Effects at Therapeutic Doses

• One case of hallucinogenic effects, increased libido, and vertigo occurred at the lowest dose (750 mg/day) in a healthy volunteer, requiring withdrawal from the study 2
• This represents an idiosyncratic reaction rather than a dose-dependent toxicity pattern
• No serious adverse events or organ toxicity were reported in controlled trials at standard dosing 3, 4

Toxicity Concerns with High-Dose or Prolonged Use

• Withaferin A, the primary bioactive compound, can cause toxicity at concentrations above NOAEL through mechanisms involving α,β unsaturated ketone binding to proteins 5
• Hepatotoxicity is theoretically possible at very high doses, though not reported in human studies at therapeutic ranges 5
• Whole plant formulations may mitigate toxicity better than isolated root or leaf extracts due to synergistic effects of multiple withanolides 5

Clinical Pitfalls to Avoid

• Avoid ashwagandha in patients with thyroid disorders without monitoring, as it can affect thyroid hormone levels 3
• Exercise caution with long-term use beyond 8-12 weeks, as safety data for extended duration remains limited 4
• Be aware that leaf extracts contain higher withaferin A concentrations than root extracts, potentially increasing toxicity risk 5

L-Theanine Overdose Potential

Critical Evidence Gap

• No clinical guidelines or research studies in the provided evidence address L-theanine overdose or toxicity
• The absence of L-theanine data in toxicology guidelines 6 and poisoning management protocols suggests extremely low clinical concern for overdose

General Medicine Context

• L-theanine is an amino acid naturally found in tea with an excellent safety profile in available literature
• Typical supplemental doses range from 100-400 mg/day
• No established toxic dose or fatal overdoses have been documented in medical literature

Practical Management Approach

Risk Stratification

• Both supplements pose minimal overdose risk compared to prescription medications like opioids 6, benzodiazepines 6, or acetaminophen 6
• Neither requires the intensive monitoring or antidote availability needed for conventional drug overdoses 6

When to Suspect Toxicity

• For ashwagandha: neuropsychiatric symptoms (hallucinations, agitation, vertigo), gastrointestinal distress, or unexplained liver enzyme elevation 2, 5
• Supportive care is the mainstay of management; no specific antidotes exist 3

Monitoring Recommendations

• If using ashwagandha doses >600 mg/day for >8 weeks, consider baseline and periodic liver function tests and thyroid panels 3, 4
• Document any psychiatric history before initiating, as idiosyncratic reactions can occur 2