Diet books and supplements cannot guarantee long-term success. For starters everyone is different and what might work for one person might not work for another. Diet books tend to be a mixture of personal opinion and healthcare facts and it's difficult to know what to completely trust. Most of the books and supplements tend to be based on current trends also and many have turned out to be inefficient.
Intravenous administration cuts off any barriers to absorption. Drugs are delivered straight to organs and this makes it quite dangerous and only used in very urgent cases where patients are unable to swallow, too young, unconscious or vomiting consistently.
