Supplements and Lopinavir.
Lopinavir, sold under the brand name Kaletra, is an HIV protease inhibitor: it blocks the viral protease that cleaves polyproteins into functional enzymes. It is a CYP3A4 substrate and is usually given with a booster.
Lopinavir is an HIV protease inhibitor. The class blocks the viral enzyme that cleaves precursor proteins into mature infectious virus, and it is almost always used within combination antiretroviral therapy. Two features drive the supplement rules. Protease inhibitors are CYP3A4 substrates with little margin for error, and the whole point of treatment is a steady drug level that keeps the virus suppressed. Ritonavir is the telling exception: at low dose it is used deliberately as a CYP3A4 inhibitor to raise the levels of the partner drug. Supplements that induce CYP3A4 push levels the wrong way and risk treatment failure and resistance. St John's Wort is the textbook exclusion here, and garlic supplements cut unboosted saquinavir levels by about half in a controlled study (Piscitelli 2001); modern boosted regimens would blunt the size of that effect but not the direction. Supplements that inhibit CYP3A4, including curcumin, quercetin, resveratrol, schisandra, berberine, boswellia and bergamot, push levels up toward toxicity instead. Bergamot is grapefruit-family citrus, and grapefruit juice doubled the amount of saquinavir absorbed in a controlled human study, which is the clearest illustration of why this class matters here. Boswellia is the least settled of them: laboratory work on the gum resin shows CYP3A4 inhibition, one study reports the opposite effect, and a literature search found no study of the combination in people, which is reason enough to keep it out of a regimen that depends on a steady level. Immune-active herbs (echinacea, andrographis, elderberry, cordyceps, astragalus) are excluded as a precaution on antiretroviral therapy regardless of CD4 count. The HIV team, not community pharmacy, signs off any supplement.
Below are the 12 documented pairs we have explicitly assessed against Lopinavir in the Distil database: 8 red, 3 amber, and 1 green. The pairs cluster around 5 mechanisms: CYP-mediated metabolism, CYP3A4 induction, CYP3A4 inhibition, P-glycoprotein induction (lowers drug levels), and Immunosuppression caution. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Last reviewed 28 August 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.
CYP-mediated metabolism
CYP3A4 induction
CYP3A4 inhibition
P-glycoprotein induction (lowers drug levels)
Immunosuppression caution
Other
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 (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyA 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.
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