Stress, Anxiety & Cortisol
"Adaptogen" is a marketing word more than a scientific one, but a few of these supplements do have real human trials for stress and anxiety. Here’s what holds up — ashwagandha has the best evidence — what’s situational, and the safety caveats that get glossed over. None of this replaces therapy or medication for clinical anxiety.
Last reviewed Jun 24, 2026 · Evidence-based — every ingredient links to its underlying studies.
- Evidence
- Moderate (several RCTs, mostly small/short)
- Who benefits most
- Day-to-day stress, stress-related poor sleep, perceived anxiety
- Who it won’t help
- Not a treatment for clinical anxiety/depression; avoid in pregnancy and with thyroid/autoimmune issues
- Effective dose
- ~300–600 mg/day of a standardized root extract (e.g. KSM-66/Sensoril)
- Time to results
- ~4–8 weeks in trials
The best-evidenced "stress" supplement — but trials are short, rare liver-injury cases exist, and it can affect thyroid hormones. Cycle it and check with a clinician if you have a thyroid or liver condition.
- Fix sleep, caffeine load, and exercise first
- Try ashwagandha or L-theanine for everyday stress
- See a clinician for persistent or clinical anxiety
- Use supplements instead of therapy/medication when you need them
- Take ashwagandha in pregnancy or with thyroid disease (without advice)
- Expect "adaptogen blends" to do much
Key point: A few of these genuinely help everyday stress; none are a substitute for treatment of clinical anxiety or depression.
What the evidence supports
- 7.5Ashwagandha— The strongest stress/anxiety RCT base of the adaptogens (see caveats above)
- 6L-theanine— Mild calm-focus; takes the edge off caffeine; fast-acting
- 8.5Magnesium— Corrects a common shortfall; supports stress response and sleep
- 7.5Saffron— Promising RCTs for low mood and mild anxiety
- 5.5Rhodiola— Better evidence for stress-related fatigue than for anxiety itself
- 6.5Glycine— Mainly a sleep-quality aid; indirect stress benefit
- 5.8Lemon balm— Small studies for acute calm; modest
- 5.5Passionflower— Traditional calming herb; limited controlled evidence
- 4GABA (oral)— Poor brain penetration when taken orally; evidence weak
- 5.5Holy basil (tulsi)— Early human data; not established
When it’s more than everyday stress
Supplements are for ordinary stress, not a substitute for care. If anxiety is persistent, interfering with life, or accompanied by low mood, see a clinician — therapy and/or medication are the evidence-based treatments, and some supplements (like St John’s Wort) interact with them.
Sources & further reading
Common questions
Does ashwagandha actually lower cortisol?
Several RCTs show modest reductions in perceived stress and cortisol versus placebo, which is why it’s the best-evidenced option here. The trials are mostly small and short, so treat it as helpful-for-some rather than guaranteed.
What’s the best supplement for anxiety?
For everyday stress, ashwagandha has the most evidence, with L-theanine and magnesium as gentler options. For clinical anxiety, supplements are adjuncts at best — therapy and medication are the proven treatments.
Is ashwagandha safe to take long-term?
Most trials run weeks, not years, so long-term safety isn’t well established. There are rare reports of liver injury, and it can alter thyroid hormones — avoid it in pregnancy and check with a clinician if you have thyroid or liver disease, are on immunosuppressants (it’s immune-stimulating), or take sedatives/alcohol (additive drowsiness). Cycling it is sensible.
Does oral GABA work for anxiety?
Probably not much — oral GABA crosses the blood-brain barrier poorly, and the human evidence is weak. L-theanine or magnesium are better-supported calming options.
Educational guidance, not medical advice. Evidence and safety details for each option live on its individual page; see a clinician for prescription treatments or persistent problems.
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