NutriStack
Garlic Extract and Propranolol, a caution.
Garlic extract lowers blood pressure on its own and, in animal studies, has been shown to potentiate the antihypertensive and cardioprotective effects of propranolol. The combination can drop blood pressure below target in well-controlled patients.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Garlic Extract and Propranolol
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Garlic extract lowers blood pressure on its own and, in animal studies, has been shown to potentiate the antihypertensive and cardioprotective effects of propranolol. The combination can drop blood pressure below target in well-controlled patients.
Mechanism. Garlic's allicin and S-allyl cysteine raise nitric oxide and H2S signaling, producing vasodilation that adds to propranolol's beta blockade and reduction in cardiac output.
Recommendation. If you take propranolol, monitor your blood pressure for several weeks after starting garlic extract. Have your prescriber re-evaluate your propranolol dose if readings consistently fall below target.
Sources (2)
- Asdaq SM, Inamdar MN. Pharmacodynamic and Pharmacokinetic Interactions of Propranolol with Garlic (Allium sativum) in Rats. Evid Based Complement Alternat Med. 2011;2011:824042. PMID 21792365
- Ried K. Garlic Lowers Blood Pressure in Hypertensive Individuals, Regulates Serum Cholesterol, and Stimulates Immunity: An Updated Meta-analysis and Review. J Nutr. 2016;146(2):389S-396S. PMID 26764326
Stack Score
How this pair moves the number.
Effect on the composite score
If both Garlic Extract and Propranolol 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 documented at /methodology/stack-score.
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