Check before you startThis one has documented interactions with medication classes where the consequences are serious. If you take any prescription medicine, run it past a pharmacist before starting.
How long to take it
Eight to twelve week courses with breaks, rather than continuous use.
Who it's actually for
People with sustained stress or poor sleep — not a general daily supplement.
Safe upper limit
UnverifiedNo formal limit; trials typically use 300–600 mg of extract daily
Rare but documented cases of liver injury, some serious. It also nudges thyroid hormones upward. Herbal, not a nutrient — no IOM/EFSA UL framework applies. The liver-injury case reports are the load-bearing safety fact and need their own citation search.
No source attached yet. Treat this as a starting point, not a citation, until reviewed.
Interactions to know about
- Thyroid medication — Levothyroxine, carbimazole, methimazole
- Sedatives / sleep medication — Benzodiazepines, zopiclone, zolpidem, opioids
- Immunosuppressants — Ciclosporin, tacrolimus, azathioprine, biologics, steroids
- Diabetes medication — Metformin, insulin, gliclazide, SGLT2 inhibitors
- Blood pressure medication — Beta blockers, calcium channel blockers, ACE inhibitors
Other supplements:
Run your full list through the interaction check.
Practical notes
- Stop and seek advice for dark urine, yellowing skin, or right-sided abdominal pain.
- Avoid in pregnancy and with autoimmune thyroid disease unless your doctor agrees.
- Sedative effects add to alcohol and sleep medication.