Energy Drinks: Caffeine Content

Griffiths and his colleagues contacted more than two dozen makers of energy drinks, asking for caffeine content. Here are some of the findings:
(The caffeine content is in milligrams per serving. Although serving sizes vary, Griffiths contends that most people will drink the entire can, whatever the number of ounces.)
Red Bull: 80 milligrams per 8.3-ounce serving
Tab Energy: 95 mg per 10.5-oz serving
Monster and Rockstar: 160 mg per 16-oz serving
No Fear: 174 mg per 16-oz serving
Fixx: 500 per 20-oz serving
Wired X505: 505 mg per 24-oz serving
In comparison, according to Griffiths:
Brewed coffee: 200 milligrams per 12-oz serving
Instant coffee: 140 mg per 12-oz serving
Brewed tea: 80 mg per 12-oz serving
Mountain Dew: 54 mg per 12 oz. serving
Dr. Pepper: 41 mg per 12-oz serving
Pepsi Cola: 38 mg per 12-oz serving
Coca-Cola Classic: 34.5 mg per 12-oz serving
Canned or bottled tea: 20 mg per 12-oz serving
Some of the energy drinks have lower caffeine contents, Griffith says. Among the lower doses:
Bomba Energy has 75 mg per 8.4-oz serving