Maccarinelli, one of the most admired fighters in British boxing, became the WBO Cruiserweight Champion in 2006 and was campaigning to line-up a world title showdown with fellow Welshman and WBO Light Heavyweight Champion Nathan Cleverly.
But in order for the 6'4" (193cm) Maccarinelli, who typically fights at 190-200 lbs (13.57 - 14.28 stone), to challenge for a light heavyweight title, he'd have to drop to 175 lbs (12.5 stone).
No easy task for a 31 year old man his height.
It was confirmed yesterday Enzo tested positive for methylhexaneamine in March following his bout with Shane McPhilbin. As a result of the failed test, the Welshman was banned from participation in all sports from 19 April 2012 to midnight on 18 October 2012.
"Following my fight against Shane McPhilbin in March, I was extremely surprised and disturbed to have tested positive for a banned substance known as methylhexaneamine, stated Enzo in a statement he released yesterday."
"I purchased a product called Dexaprine that contained this banned substance from a combat magazine. The advert stated that it was an approved substance and I checked the ingredients which had no reference to any banned substance that I was aware of. In fact, it also stated that it was suitable for athletes."
The amiable Maccarinelli added, "I have since found out that this 'fat burner' contained a substance and consequently I failed a dope test, albeit with a very low reading."
"I wish to state that this substance was in no way used to gain any advantage in the ring or enhance my performance and whilst I appreciate that it may look that way, I would certainly never cheat or cut corners in my preparation."
Enzo has volunteered to assist United Kingdom Anti-Doping (UKAD) in any way he can to prevent other sportsmen from being put in a similar situation and has vacated his British Cruiserweight Championship insisting.
"I could not bear the thought of holding such a prestigious championship if anyone thought that I hadn't won it fairly."
The remorseful Welshman added, "I am very conscious of my reputation within the sport of boxing and even prior to the decision, that has been released today, I promised to fully accept any punishment that was given as a result of this positive test."
Enzo's statement, in its entirety, can be found on BBC.
What is Methylhexaneamine?
Methylhexaneamine, an extract from the geranium plant, is a compound found in nasal decongestants that has been labelled by many amateur and professional sports entities as a performance enhancing drug (PED) and is consequently banned. Nevertheless, it can be found in nutritional supplements, especially those aimed at promoting weight loss.
Although it's considered a fairly weak, short-acting stimulant, Methylhexaneamine is known to produce a heightened sense of awareness and energy, and it can mask fatigue levels.
To maximize its fat-burning effects, methylhexaneamine is often used with other stimulants such as coffee and Ephedrine.