What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the Garlic Extract + Losartan/Hydrochlorothiazide pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Prescription·a caution·Moderate evidence

Garlic Extract + Losartan/Hydrochlorothiazide

Q: Can I take Garlic Extract and Losartan/Hydrochlorothiazide together?

Possibly, but with caution. Garlic Extract and Losartan/Hydrochlorothiazide have a documented caution-tier interaction. Garlic extract has a modest blood-pressure-lowering effect in hypertensive patients. When added to an effective antihypertensive combination such as losartan plus hydrochlorothiazide, the cumulative effect is usually small but can occasionally produce additive hypotension, particularly in volume-depleted patients or after dose escalation of the medication.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Caution Moderate evidence

Garlic extract has a modest blood-pressure-lowering effect in hypertensive patients. When added to an effective antihypertensive combination such as losartan plus hydrochlorothiazide, the cumulative effect is usually small but can occasionally produce additive hypotension, particularly in volume-depleted patients or after dose escalation of the medication.

Supplement × Prescription

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

Garlic Extract and Losartan/Hydrochlorothiazide

Pair type

Caution

Evidence

Moderate

Source citations

Scope

Supplement × Prescription

Last verified

June 4, 2026

CautionModerate evidence

What is happening. Garlic extract has a modest blood-pressure-lowering effect in hypertensive patients. When added to an effective antihypertensive combination such as losartan plus hydrochlorothiazide, the cumulative effect is usually small but can occasionally produce additive hypotension, particularly in volume-depleted patients or after dose escalation of the medication.

Mechanism. Allicin-derived compounds promote nitric-oxide-mediated vasodilation, adding modestly to the antihypertensive effect of the losartan/hydrochlorothiazide regimen.

Recommendation. Garlic extract is generally compatible with this combination and is unlikely to cause problems at culinary or standard supplement doses. Patients should monitor for dizziness or lightheadedness, especially when starting therapy or when the diuretic causes volume loss, and report sustained low readings to their clinician.

Stack Score

How it moves the number.

Effect on the composite score

If both Garlic Extract and Losartan/Hydrochlorothiazide are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).

The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Ried K, Frank OR, Stocks NP. Aged garlic extract reduces blood pressure in hypertensives: a dose-response trial. Eur J Clin Nutr. 2013.Needs sourceNo link
2Rohner A, et al. A Systematic Review and Metaanalysis on the Effects of Garlic Preparations on Blood Pressure. Am J Hypertens. 2015.Needs sourceNo link

Check your full routine

One pair was the worked example.

Drop your supplements and prescriptions into NutriStack and it runs every pair at once: every interaction, synergy, timing rule, and contraindication, each linked to its primary source.

Open the interaction checker → Browse the research index