According to Mayo Clinic, adults should try to stay under 400 milligrams of caffeine consumption per day, while adolescents should drink no more than 100 milligrams of caffeine in a day or avoid it altogether. Excessive ... More »

www.reference.com Health Medications & Vitamins Side Effects

The effects of caffeine on the human body include an increase in performance, mood elevation, mental and cognitive improvement, headaches and an inability to sleep, according to information housed on the University of De... More »

www.reference.com Health Nutrition & Diets

Caffeine has a half-life of between three and five hours; it remains in the bloodstream for about 14 hours, according to the American Academy of Sleep Medicine. While caffeine can increase an individual's alertness, it b... More »

www.reference.com Health Medications & Vitamins Side Effects

Too much caffeine can cause nervousness, irritability and sleeplessness, and Zantrex-3 contains 300 milligrams of a mixture of caffeine and caffeine-like stimulants, according to the manufacturer's website. People who ar... More »

www.reference.com Health Medications & Vitamins Side Effects

The negative side effects of GAKIC include shakes, nervousness, nausea and vomiting due to 300 milligrams of caffeine per serving, according to a review by Dietspotlight.com. More serious side effects include increased h... More »

www.reference.com Health Medications & Vitamins Side Effects

Biotin tablets are not known to cause side effects when amounts of up to 10 milligrams per day are ingested, according to Mayo Clinic. Biotin is a B-complex vitamin that functions as a component of enzymes which breaks d... More »

www.reference.com Health Medications & Vitamins Side Effects

Drinking coffee containing caffeine can lead to insomnia, nervousness, upset stomach and headache in some individuals, states WebMD. Coffee is safe for most adults, but drinking more than six cups per day can cause sympt... More »

www.reference.com Health Medications & Vitamins Side Effects