Matcha is also rich in the amino acid L-theanine. L-theanine is believed to promote alpha waves in the brain, and possibly raise the levels of Dopamine, Serotonin and GABA, and those are neurotransmitters that play a very important role in determining mood and mental state. This is the reason why L-theanine is believed to have the ability to reduce stress, boost mood, and get you closer to that sense of cognitive synergy. The combined effect of L-theanine and caffeine is believed to be responsible for what is called the "calming focus" that is often described by Matcha drinkers.
The 4 Matcha Benefits You Need to Know!
ENHANCES CALM AND PROMOTING FOCUS
HIGH IN ANTIOXIDANTS
Matcha contains significantly more antioxidants than regular green tea, and more antioxidants than any "super-food". 
BOOST METABOLISM + BURN CALORIES
Drinking Matcha green tea is believed to increase metabolism and help the body burn fat faster than average. 
Matcha has significantly less caffeine than coffee (around 34mg per serving of Matcha compared to 90-200mg per serving of regular coffee), but the caffeine in Matcha is believed to be slowly absorbed into the body producing long lasting energy (up to 4-6 hours) with less likelihood of jitters.
1- Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. American Journal of Clinical Nutrition 70(6), 1040-1045. [PubMed]
2- The effects of green tea on weight loss and weight maintenance: a meta-analysis. International Journal of Obesity 33, 956-961. [PubMed]
3- L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance. [PubMed]
4- The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent. [PubMed]
5- L-Theanine reduces psychological and physiological stress responses. [PubMed]
6- Determination of catechins in matcha green tea by micellar electrokinetic chromatography. [PubMed]
7- Matcha Green Tea Drinks Enhance Fat Oxidation During Brisk Walking in Females. [PubMed]
8- Effect of Green Tea Phytochemicals on Mood and Cognition. [PubMed]