1. Caffeine source. Both functional and conventional energy drinks contain caffeine that can help you feel more alert and active throughout the day. Functional energy drinks brands like Celcius For example, the FDA reports that a 12-ounce can of soda has 30 to 40 milligrams of caffeine, while an 8-ounce cup of coffee provides 80 to 100 milligrams. Green tea and black tea contain around 30 to 50 milligrams of caffeine, while energy drinks can have up to 250 milligrams per 8 ounces. Symptoms of anxiety and the effects of caffeine affect the activity of the sympathetic nervous system, the part of the autonomic nervous system that controls the body's fight-or-flight response. The fight-or-flight response refers to the way your body mobilizes and responds to threats in the environment. When activated, this response triggers a If you don’t have time to wait in line for a handmade drink, or to home-brew your own coffee, keep your eye out for this Doubleshot Energy trio in local Starbucks stores, 7-11, and grocery stores this June. MSRP is USD $2.59 per can and they come as singles, 4 packs, and 12 packs. NOW available on-line from Amazon. Overall Score: (5/5) Review A 16 fl. oz. can of Monster Energy Drink contains 160 mg of caffeine, 54 grams of sugar, 210 calories, and energy-boosting ingredients such as taurine, B-Vitamins, and guarana extracts. Monster Energy is currently one of the most popular energy drink brands with 5.9% global market share. The 160 mg caffeine content of Monster Energy …. 9. Vulnerability to Caffeine Affected by Tolerance and Genetic Factors. Vulnerability to caffeine intoxication after bolus caffeine doses, such as those delivered in energy drinks, is markedly affected by pharmacological tolerance. Tolerance refers to a decrease in responsiveness to a drug as a result of drug exposure. 3. 5-Hour Energy Drink. 5-Hour Energy comes in small two-ounce bottles — but they really pack a punch! A bottle of regular strength 5-Hour Energy has an impressive 200 milligrams of caffeine, about twice as much as a cup of coffee. And if you opt for the extra strength variety, you can expect over 242 milligrams. The manufacturers claim the drink will give you 5 hours of energy without crashing. The drink is non-carbonated and sweetened with Sucralose (Splenda). Variations. 5 Hour Extra Strength caffeine amount is 230 mg. 5 Hour Tea Shots have 200 mg of caffeine per bottle. 5 Hour Energy Drinks have 200 mg per 16 fl oz can; Flavors of 5 Hour Energy lwHP.