An amino acid precursor to dopamine and noradrenaline, with some evidence for cognition under acute stress.
TrustedSupp Tier System™ · Tier 3Take as a defined course
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.
Evidence strength
40/100Limited
WEAKLIMITEDMODERATESTRONGVERY STRONG
What the evidence supports: working memory and cognition under acute stress in small trials.
This scores how well-supported the claim above is — not how much benefit you personally would get. A high score on a narrow claim does not extend to everything the product is marketed for.
How long to take it
Situational — before demanding, stressful tasks — rather than daily.
Who it's actually for
People looking for acute cognitive support under stress or sleep deprivation.
Safe upper limit
Unverified
No formal upper limit; short-term studies used single doses of 100–150 mg per kg body weight
Generally well tolerated short term. It is a building block for thyroid hormone and adrenaline-family chemicals, which is why it interacts with thyroid medication, levodopa, and MAO-inhibitor antidepressants.