What it is
Ashwagandha (Withania somnifera) is a plant from Ayurvedic medicine sold as "anti-stress" and "for better sleep". Trials with root extracts observe small reductions in perceived stress and anxiety scores and some improvement in sleep, with short studies of uneven quality.
There are no authorised health claims in the EU for this plant, so it cannot be said to reduce stress or anxiety. And a reason for caution has emerged: cases of liver injury have been described in association with its use, as well as its effect on the thyroid.
What is known
What trials have measured and what they have not:
- Trials use standardised root extracts for 8-12 weeks, with small effects on perceived stress.
- It can raise thyroid hormones and have a sedative effect; hence the need to ask about the thyroid and about what they take to sleep.
- There are no long safety studies, nor in pregnancy, breastfeeding or children.
At the counter
When to recommend it
- A healthy adult, with no thyroid or liver disease, who wants to try it with realistic expectations and for a few weeks
- With the warning that it is a trial with an end date, not a treatment for stress
- After judging that the discomfort does not need a consultation
When not to
- Pregnancy and breastfeeding: contraindicated for lack of data and risk to the pregnancy
- Thyroid disease or treatment with levothyroxine; liver disease; autoimmune diseases
- With sedatives, benzodiazepines or antidepressants, and 2 weeks before surgery
Warnings
- Important LIVER: cases of liver injury have been described. With jaundice, dark urine, itching or persistent malaise: stop taking it and assess.
- Important THYROID AND SEDATIVES: it can raise thyroid hormones and potentiate sedatives. Ask about levothyroxine, benzodiazepines, antidepressants and sleeping medicines.
- Caution Pregnancy, breastfeeding, autoimmune diseases and upcoming surgery: do not recommend it.
- Caution If what they want is a way out of anxiety or insomnia lasting weeks, the answer is not an adaptogen: it is a consultation.
Pharmacokinetics
- Absorption
- Poorly understood: it depends on the extract and its withanolide content.
- Distribution
- Not well characterised in humans.
- Metabolism
- Hepatic; cases of idiosyncratic liver injury have been reported.
- Elimination
- Not well characterised.
What the label says versus what is authorised
| Aspect | Usual label | What may be claimed |
|---|---|---|
| Stress and anxiety | "Reduces stress" | Nothing: no authorised claim |
| Sleep | "Improves sleep" | Nothing: no authorised claim |
| Safety | "100 % natural, no side effects" | Liver injury and an effect on the thyroid have been described |
Natural is not a synonym for safe: a plant with a real effect can have real adverse effects.
Self-assessment
Three questions. When you check your answers you will see the explanation for each one.
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They can indicate liver damage, which has been associated with its use.
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It can raise thyroid hormones and disturb the control of treatment.
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Without an authorised claim, it cannot be stated. The evidence can be explained as limited.
Training content. It does not replace the summary of product characteristics or clinical judgement.