Garlic supplements are known to boost the function of the immune system. One large, 12-week study found that a daily garlic supplement reduced the number of colds by 63% compared to a placebo. The average length of cold symptoms was also reduced by 70%, from 5 days in the placebo group to just 1.5 days in the garlic group. Another study found that a high dose of aged garlic extract (2.56 grams per day) reduced the number of days sick with cold or flu by 61%.

Garlic supplements are known to boost the function of the immune system. One large, 12-week study found that a daily garlic supplement reduced the number of colds by 63% compared to a placebo. The average length of cold symptoms was also reduced by 70%, from 5 days in the placebo group to just 1.5 days in the garlic group. Another study found that a high dose of aged garlic extract (2.56 grams per day) reduced the number of days sick with cold or flu by 61%.