The short answer
Both torsemide and St John’s wort have photosensitivity concerns, but their combined effect has not been measured. St John’s wort studies show dose- and preparation-dependent findings, including null results.
What this answer covers
Oral Hypericum perforatum with oral torsemide; topical oil and pure hypericin are separate exposures.
- Supplement or preparation
- Hypericum perforatum
- Medication ingredient
- torsemide
Separate risks do not quantify an interaction
Torsemide’s label includes photosensitivity among voluntary postmarketing reports, where frequency and causality may be uncertain. Federal guidance also notes sun-related skin reactions with large oral St John’s wort doses or topical use. Together these support a precaution, not proof of additive harm.
Some oral studies were reassuring
A study in 72 volunteers found no significant change in erythema or pigmentation measures after LI 160 extract, apart from a marginal pigmentation finding. No torsemide users were studied, and the results do not establish safety for every dose or preparation.
Higher exposure gave a different signal
Another study found modest increases in laboratory light sensitivity after repeated high-dose LI 160 exposure, while most single-dose comparisons were unchanged. Light-test changes are not the same as a demonstrated combined-treatment sunburn rate.
Review unusual skin reactions
Discuss the exact supplement and other medicines with the treating team. Take unusual sun sensitivity seriously and seek assessment for a severe or blistering rash. Neither spacing the doses nor changing torsemide yourself is an established prevention strategy.
Evidence and practical considerations
Side effects & toxicity
Retain only an indirect overlapping-photosensitivity precaution. No combination study, uncertain postmarketing causality and null/preparation-dependent botanical findings limit the claim.
- Exact scope
- Oral Hypericum perforatum with oral torsemide; topical oil and pure hypericin are separate exposures. with Oral torsemide, exact RxCUI38413 IN; not all loop diuretics or parenteral exposure.
- Medication form and route
- oral torsemide; oral supplement
What remains uncertain
- Source-specific identity and endpoint limits apply; no unstudied dosing recommendation.
Factors that may matter: Dose and duration; Kidney function; Exact preparation; Other medicines.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed oral torsemide for edema or hypertension.
Excess diuresis may cause dehydration, hypotension and worsening renal function. Electrolyte abnormalities include hypokalemia; monitor serum electrolytes. Low-dose hypertension studies showed small average potassium decreases, with no universal deficiency. Photosensitivity appears among postmarketing reports.
How this applies: Interpret only for the stated species, preparation, route and endpoints; exact torsemide pair evidence is distinguished.
No named botanical interaction for this batch. Postmarketing reports cannot establish frequency or causality. Potassium replacement is not required for every patient.
Source 2: regulatory guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: People using the specified oral preparation.
Large oral doses or topical use may cause severe skin reactions following sun exposure.
How this applies: Interpret only for the stated species, preparation, route and endpoints; exact torsemide pair evidence is distinguished.
No torsemide co-use study; independent risks do not quantify additive photosensitivity.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 72 volunteers.
No significant effect on erythema or pigmentation indices apart from a marginal UVB pigmentation signal in the single-dose study.
How this applies: Interpret only for the stated species, preparation, route and endpoints; exact torsemide pair evidence is distinguished.
Healthy skin types II and III; no torsemide; results do not rule out other doses, products or individual phototoxic reactions.
Source 4: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 13 volunteers in single-dose phase and 50 in repeated-dose phase.
Single-dose solar-simulated sensitivity unchanged; highest dose had marginal UVA effect. Repeated high-dose exposure modestly increased UVA and solar-simulated sensitivity.
How this applies: Interpret only for the stated species, preparation, route and endpoints; exact torsemide pair evidence is distinguished.
Higher-than-typical doses and laboratory light thresholds, not torsemide-associated sunburn events.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared exact-pair article with preparation boundaries and qualified current-claim conclusions. | |
| Research summary published |
Article revision: 831f67fb9be5b9da
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.