An essential amino acid, tyrosine plays a key role in the production of several important brain chemicals. Although your body naturally produces tyrosine from phenylalanine (another type of amino acid), some people take tyrosine supplements for a variety of health-related purposes. For example, some proponents claim that tyrosine supplements can help boost your brain function and sharpen your memory.
Several small studies suggest that tyrosine supplements may help improve brain function. In a 2007 study of 19 people, for example, scientists found that use of tyrosine supplements helped guard against the detrimental effects of severe cold exposure on cognitive performance and memory. However, more research is needed before tyrosine supplements can be recommended as a memory-enhancer.
To keep your memory sharp as you age, make sure to get regular cardiovascular exercise, follow a diet high in antioxidants, manage your stress, and stimulate your brain with challenging activities. Increasing your intake of omega-3 fatty acids may also help preserve your memory. Read the full article: Tyrosine - What You Need to Know.
Yes I have read similar articles before I have been trying to get more info about how the studies were conducted.