What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
Can you take iodine and L-tryptophan together?
Nobody has tested this pair.
As of August 2026, no human trial has given iodine and L-tryptophan together. We searched PubMed for trials naming both on 26 August 2026 and read every candidate it returned; none tested the pair.
17 studies · none tested the actual pair · 1 caution
See what each one is on its own
What you’re seeing
- Iodine renders half-there: for thyroid, the science is still forming.
- L-tryptophan renders a ghost: for sleep, almost nobody has looked.
- Nothing is drawn between them, because nothing has been run. The empty space is the review.
You can tell before you read a word.
Vitamin D + vitamin K2 is what the other answer looks like. Someone ran the study, so a cord is drawn between them. That is the whole difference.
Fair questions
Is it safe to take iodine and L-tryptophan together?+
No trial has tested the combination, so there is no evidence either way. Nobody has found a problem, and nobody has looked.
Why does this page say nobody has tested it?+
Because we ran the search and read the results. The date above is the day we ran it. We do not claim a pair is untested without a logged search behind it.
Will this page change?+
Yes, if a trial publishes. We re-run these searches and the page changes from air to a cord the day the evidence does.
Deeper
The search we ran+
On 26 August 2026 we asked PubMed for trials, reviews and meta-analyses naming both iodine and L-tryptophan. It returned 1 candidate. We read every one and none gave the two together. This page carries a date because the answer can change: if a trial publishes, the air becomes a cord.
What each one is on its own+
Iodine
- Thyroidhalf-there
- Cholesterolhalf-there
- Immunity and coldshalf-there
- Jointshalf-there
- Memory and focushollow
L-tryptophan
- Sleepa ghost
Pairs that have been tested+
- L-tryptophan has been tested with glycine.
These are the combinations someone has actually run a study on. Every other pairing here is air.
Worth knowing+
- Iodine: What the research mostly asks is whether correcting a shortage helps: trials in populations that were deficient, and supplementation in pregnancy. Very little of it asks whether extra iodine helps someone who already gets enough, so this page cannot answer that question.