1-2 cloves/day (4g fresh garlic, or 600-1200mg aged garlic extract) reduced systolic BP by 8-10 mmHg in hypertensive patients — comparable to some medications. Allicin → H2S (hydrogen sulfide) → relaxes blood vessels. Effect takes 2-4 weeks of daily intake.
Daily garlic reduced cold frequency 63% and cold duration 70% in a 12-week RCT (146 participants). Allicin has direct antiviral and antibacterial properties. The placebo group got 24 colds; the garlic group got 8.
Meta-analysis: garlic reduces LDL 8-10% in people with high cholesterol. Effect is modest but real. Aged garlic extract is more effective than raw garlic for cholesterol (less GI irritation, standardized dosing).
Allicin metabolites (allyl methyl sulfide) are excreted through lungs and skin — not just breath. This lasts 24-48h after eating garlic. This is not a side effect — it's how the compounds circulate through your body and do their work. You can't "deodorize" garlic's health effects without removing the health effects.
Parsley, mint, apple, and milk reduce garlic breath (not body odor). Enteric-coated garlic supplements reduce breath odor but also reduce allicin (the active compound). You're trading effectiveness for social acceptability.