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 selenium and probiotics together?
Tested together, early signs.
As of August 2026, selenium and probiotics have been tested together in 1 trial, in pregnant women with gestational diabetes, and the one trial so far came out ahead of placebo. Scored under the same rules as everything here.
7 studies · 1 tested the actual pair
What you’re seeing
- Selenium renders solid: for thyroid, it is well studied and it works.
- Probiotics renders solid: for gut and digestion, it is well studied and it works.
- The woven cord is the rare part: one trial gave both together, and the one trial so far came out ahead of placebo.
You can tell before you read a word.
Magnesium + L-theanine are sold together in the same aisle. No trial has ever tested the pair. When that is true, we draw nothing between them. The nothing is the review.
The pair trial
- 2022Randomized trial · 60 people · pregnant women with gestational diabetes · the pair helpedsource
The other 6 studies on file tested each one alone. See all 7 studies
Fair questions
Is it safe to take selenium and probiotics together?+
The studies on this page gave both together and reported no harm from the combination. That is not the same as a safety trial, and it says nothing about your dose or your medication.
How many studies is this based on?+
1 that gave the pair together. The papers are listed above with links to the source.
Deeper
What each one is on its own+
Selenium
- Thyroidsolid
- Cancer preventionhollow
- Jointshalf-there
Probiotics
- Gut and digestionsolid
- Energy and fatiguehalf-there
- Moodsolid
Pairs that have been tested+
- Selenium has been tested with L-carnitine, L-arginine, vitamin D, CoQ10, vitamin E, inositol.
- Probiotics has been tested with magnesium, berberine, L-glutamine, L-arginine, vitamin D, turmeric.
These are the combinations someone has actually run a study on. Every other pairing here is air.