“There’s too much blood in my caffeine system” is a jocular saying that has been printed on many gift items, such as posters, T-shirts and coffee mugs. The saying has been cited in print since at least 1994.
 
         
West Coast Online
WCO issue # 19, September 1994, page 23
Taglines & signatures
(...)
There’s too much blood in my caffeine system.
 
Google Books
The Greatest Joke Book Ever
By Mel Greene
New York, NY: Avon Books
1999
Pg. 241:
There’s too much blood in my caffeine system.
 
Google Books
The Java Tutorial (Second Edition)
By Mary Campione and Kathy Walrath
Reading, MA: Addison-Wesley
1999
Pg. 325:
There’s too much blood in my caffeine system.
 
23 September 2004, The Press of Atlantic City (NJ), “Speedo Must Love It”:
One member of the panel, who eventually was dismissed, got a laugh with her bumper sticker: “There’s too much blood in my caffeine system.”
     
The Daily Star—Weekend Magazine (Bangladesh)
Volume 4 Issue 39 | March 25, 2005
Lines to live by . . .
(...)
*There’s too much blood in my caffeine system.
 
Google Books
The Snark Handbook:
Insult Edition: Comebacks, Taunts, and Effronteries
By Lawrence Dorfman
New York, NY: Skyhorse Publishing
2010
Pg. ?:
There’s too much blood in my caffeine system.
     
PsychologistMimi
Ode to Coffee 1015 on a Saturday Night
posted on AUGUST 4, 2012
(...)
I now live in New York, and do what I can to make sure I don’t have too much blood in my caffeine system. People complain that everywhere you travel in the world you find Starbucks. I find this delightful. It’s my anchor to reality.