Weight loss pills sound a bit bullshit.
If anything Id think they would stimulate to shit like mad.
Mayorga got fined for using diuretics before the De la Hoya fight.
Diuretics are used to treat heart failure, liver cirrhosis, hypertension and certain kidney diseases. Diuretics alleviate the symptoms of these diseases by causing sodium and water loss through the urine. As urine is produced by the kidney, sodium and water – which cause edema related to the disease – move into the blood to replace the volume lost as urine, thereby reducing the pathological edema. Some diuretics, such as acetazolamide, help to make the urine more alkaline and are helpful in increasing excretion of substances such as aspirin in cases of overdose or poisoning. Diuretics are often abused by sufferers of eating disorders, especially bulimics as a weight loss attempt.
In other words, he popped pills to piss a lot so he could lose water weight and make the limit.