Just because its chemically similar to something we almost universally respond too doesn't mean it will work. If I remember correctly from my biology class, the human body doesn't know what to do with chlorophyll other than filter it out. , for oxygen 100 percent to work it must be inhaled through your lungs where it rapidly gets forced into the blood stream and carried to the brain.

Chlorophyllin (water extract of chlorophyll) does have some interesting pharmacological activity.

In this study, it has anti-inflammatory activity and causes cancer cells to self-destruct. The NF-κB is responsible for kicking off the inflammatory cascade, which causes all kinds of problems if it is turned up too high too long.

"Dietary chlorophyllin inhibits the canonical NF-κB signaling pathway and induces intrinsic apoptosis in a hamster model of oral oncogenesis." Pubmed 22210229