Our Research on Garlic suggests:

Garlic bulb and clove
Garlic (Allium sativum) belongs to the most commonly used health supplements.
When the bulb is crushed or chewed, Alliin, one of the compounds found in Garlic, becomes Allicin, which is said to block key enzymes that aid bacteria in their effort to invade and damage tissues. But cooking Garlic inhibits the formation of Allicin.
• The Cherokee did use garlic as an expectorant for coughs.
• In 1858, Louis Pasteur observed garlic's antibacterial activity.
• Studies in humans have suggested possible cardiovascular benefits.
• A BBC news story reported that garlic may prevent and fight the common cold.
• A Czech study found garlic supplementation reduced accumulation of cholesterol on vascular walls.
• A study found garlic supplementation significantly reduced aortic plaque deposits.
• A study showed that supplementation with garlic inhibited vascular calcification in human patients with high blood cholesterol.
Precaution:
Very high quantities of garlic (plant or supplements) may increase the risk of bleeding since garlic can thin the blood somehow like aspirin. Ingesting more than 10 raw cloves per day can be toxic.
Verdict:
To profit from the benefits of the active garlic ingredient, Allicin, you must eat raw garlic, since cooking inhibits the formation of Allicin. To avoid the strong odour of garlic in your breath, your choice would be Garlic capsules equivalent to 1000 mg of fresh garlic clove.