Both have blood-thinning properties through different mechanisms; the combination may increase bleeding risk.
Nattokinase has direct fibrinolytic activity. Garlic inhibits platelet aggregation via ajoene.
Inform your doctor if using both, particularly before surgery or alongside anticoagulant drugs.
Known drug category interactions for these supplements. Especially relevant if you take prescription medications.
Concentrated garlic supplements may mildly enhance anticoagulant effects.
Food-level garlic is generally fine. Inform your doctor if taking concentrated garlic extract with blood thinners.