Sulforaphane (Broccoli Sprout Extract) and medications.
Sulforaphane (Broccoli Sprout Extract) is classified as a optimise supplement in the Distil database, evidence Grade C. The page below lists every medication we have explicitly assessed it against.
Sulforaphane comes from broccoli sprout extract, where glucoraphanin is converted to the active compound by the enzyme myrosinase. Its main mechanism is activating the Nrf2 pathway, which switches on phase II antioxidant and detoxification enzymes. The Nrf2 effect in humans is reasonably solid, but the downstream outcomes are Grade C: the flagship prediabetes trial missed its main glucose target and achieved only a modest reduction, and a former-smoker study showed a cancer biomarker shift rather than a clinical endpoint. Response varies a lot because roughly a third of adults lack the gut bacteria needed to release sulforaphane, so frame it as adjunctive support behind diet, weight and exercise. Form matters: choose a glucoraphanin extract with active myrosinase, and avoid heat, which destroys the enzyme. On interactions, the brassica goitrogen concern is minimal at adequate iodine intake, but flag TSH monitoring for anyone on levothyroxine. Defer to a GP on narrow-window drugs like tacrolimus, ciclosporin, sirolimus or warfarin, and exclude in pregnancy and active chemotherapy.
Below are the 6 documented pairs we have explicitly assessed for Sulforaphane (Broccoli Sprout Extract): 6 caution. The pairs cluster around 2 mechanisms: Brassica goitrogen effect (theoretical) and Nrf2 + CYP modulation. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Last reviewed 14 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Brassica goitrogen effect (theoretical)
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Levothyroxine?
Brassica vegetables (broccoli, cabbage, kale) contain compounds that in theory could slightly affect thyroid hormone production by competing with iodine uptake. A 2024 systematic review found minimal real-world risk in humans with adequate iodine intake, so this is a cautious flag rather than a strong warning. If you are starting sulforaphane while on levothyroxine, ask your GP to check your TSH at the next routine blood draw and make sure you are getting enough iodine.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Nrf2 + CYP modulation
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Ciclosporin?
Sulforaphane activates a body-wide antioxidant pathway (Nrf2) that can also subtly affect liver enzymes responsible for clearing ciclosporin. The effect at supplement doses is uncertain, but for a narrow-window drug like ciclosporin the cautious path is to discuss with your transplant team before starting.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Everolimus?
Sulforaphane activates a body-wide antioxidant pathway (Nrf2) that can also subtly affect the liver enzymes responsible for clearing everolimus. The effect at supplement doses is uncertain, but for a narrow-window drug like everolimus the cautious path is to discuss with your transplant or oncology team before starting.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Sirolimus?
Sulforaphane activates a body-wide antioxidant pathway (Nrf2) that can also subtly affect liver enzymes responsible for clearing sirolimus. The effect at supplement doses is uncertain, but for a narrow-window drug like sirolimus the cautious path is to discuss with your transplant team before starting.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Tacrolimus?
Sulforaphane activates a body-wide antioxidant pathway (Nrf2) that can also subtly affect liver enzymes responsible for clearing tacrolimus. The effect at supplement doses is uncertain, but for a narrow-window drug like tacrolimus the cautious path is to discuss with your transplant team before starting.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Caution Does Sulforaphane (Broccoli Sprout Extract) interact with Warfarin sodium?
Sulforaphane affects liver enzymes responsible for clearing warfarin (mainly CYP2C9). The direction and magnitude in humans at supplement doses are not well characterised. Tell your GP and ask whether INR monitoring should be tightened for the first few weeks.
Evidence: No direct study of this exact combination yet; the caution rests on a plausible mechanism or on reports involving a related medicine.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
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How the checker decides
Every result has a source
Each pair we have assessed is cited to a published study (PMID) or the British National Formulary, so you can read the source yourself.
Four kinds of answer
Severe, caution, no known interaction, and not yet assessed. A pair we have not assessed is never shown as clear.
- Severe
- Caution
- No known interaction
- Not yet assessed
Nothing in our data is not a clearance
When nothing in our data records a problem with a pair, the result says no known interaction at typical doses, which is not a clearance: your pharmacist or GP can check the pair against your full medical history.
A full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
£49 until 30 June 2027 · £79 from 1 July 2027.
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