Interaction map
Pick what you take. The graph draws every interaction we have a source for among your picks, through the pathway it runs through: liver enzymes, absorption, serotonin, bleeding, lab tests and more. Tap a line, or use the list under the graph, to see its source and what to ask.
Tool · Kymata Health 20 graded entries · 147 pairs from labels and NIH · 22 PubMed records Researched and written by Kymata Health Editorial · Sources cited inline · Checked October 10, 2026 Checker view Report an error
Can I take these together?
Interaction graph · substances, enzyme hubs, effect hubs
Sourced from PubMed, FDA labels and NIH · checked Oct 23, 2026Browse the full list (42)
Medicines
Supplements
Food and drink
Sertraline St John's wort
St John's wort with an SSRI can cause serotonin syndrome
Both are thought to raise serotonin activity, so together they can push it too high (inferred).
Suspected pathway, not shown in trials.
To discuss with a pharmacist or clinicianDo not combine without your prescriber's advice. Agitation, tremor, sweating, fever or muscle twitching after starting St John's wort needs urgent care.
Checked October 10, 2026
6 curated interactions · 1 from labels and NIH · 0 predicted · 8 pairs not on our list · 7 picked
Legend · how to read the graph
- Major
- Avoid the combination unless your prescriber advises otherwise.
- Moderate
- Can change how well a medicine works or what a lab test shows; worth a conversation and sometimes a dose or timing change.
- Minor
- Small or theoretical effect.
- Solid line
- The effect was shown in studies, or a drug label or NIH page names the pair in its own words.
- Dotted line
- Suspected or predicted from how each works, not shown in a study of the pair. Predictions come from sourced facts about each one (FDA tables, drug labels) and are never rated major.
- Grey dashed
- Not on our list. No study entry, drug label or NIH page on our list covers this pair. That is not the same as safe.
- Enzyme hub
- Breakdown by liver enzymes: one substance changes how fast the other is cleared.
- Effect hub
- A shared effect or route: absorption, serotonin, bleeding, blood sugar, hormones, lab tests. Lines run through their hubs.
How does the interaction map work?
One graph for everything you take
Pick medicines and supplements by generic or brand name. Every interaction we have a source for is drawn at once, through the pathway it runs through: liver enzymes, absorption, serotonin, bleeding, blood sugar, hormones or lab tests. When three or more of your picks add to the same risk, such as bleeding, they share one line into that hub, with every pair listed.
Every line is sourced
Studied pairs carry a severity, an evidence grade and the PubMed records behind them, with study design and size. Pairs an FDA drug label or NIH page names are drawn solid and quote that source word for word; their severity comes from its wording. Where the concern comes only from how each works, the line is dotted, is never rated major, and shows the sourced facts it rests on.
Gaps are shown, not hidden
A medicine pair with no entry is drawn as a grey dashed line and labelled not on our list. That is not the same as safe; the print sheet lists those pairs so you can ask about them.
Private by design
What you pick stays in your browser. Saved combinations live in this browser only, and nothing about what you take goes into the address bar or analytics.
Questions people ask
Can I take St John’s wort with sertraline or another SSRI?
Our list rates this combination major. A case series described serotonin syndrome in five older adults who combined prescription antidepressants with St John’s wort, and the same risk is expected with any SSRI. Do not combine them without your prescriber’s advice.
How far apart should levothyroxine and calcium or iron be?
Do not swallow them together. In small studies, calcium carbonate and ferrous sulfate taken with levothyroxine lowered free T4 and raised TSH. Ask your prescriber or pharmacist how far apart to take them, and whether to recheck TSH.
Does fish oil interact with antidepressants?
Our list rates it minor, and the pair itself has not been studied. SSRIs were linked to more stomach bleeding, while fish oil did not raise bleeding around heart surgery in a 1,516-patient trial. Mention both before surgery or if you also take NSAIDs, aspirin or blood thinners.
What does it mean when a pair is not on the list?
It means no study entry, drug label or NIH page on our list covers that pair. It does not mean the pair is safe together. The map draws it as a grey dashed line and the print sheet lists it so you can ask a pharmacist about it.
How is each interaction checked?
There are three kinds of line. Studied pairs cite PubMed records that were opened and read, with the study design and size, and get a severity and an evidence grade: A for several controlled studies or a finding in the product’s dosing guidance, B for at least one controlled human study, C for case reports, observational data or mechanism only. Pairs an FDA drug label or NIH page names are quoted word for word and linked to that section; their severity comes from the source’s wording, and every quote is re-checked against the source. Dotted lines are predictions from sourced facts about each substance, such as the FDA’s table of enzyme roles; they are never rated major.
Related tools
- Interaction checkerThe same curated entries as a list, one medicine at a time.
- Day SimulatorPlace what you take on a 24-hour chart and see each supplement's rise and fall from published half-lives, plus the spacing rules from FDA labels your schedule crosses.
- Label X-RayPhotograph a Supplement Facts panel and see each line beside the doses and forms used in human trials, any upper limit, and blends that hide their amounts.
- Evidence EngineRe-pool trials on knee arthritis pain, hot flashes, falling asleep, HbA1c, PCOS and muscle in older adults by age, dose and duration. Every number cited.