Well, there is no supplement for the results you're trying to acchieve, unless someone else has an idea...
What I reccomend with regards to nutrition, is perhaps a good meal 2 hours before your exercise, which should last 1.5 to 2 hours.
There are different studies that look at the absorbtion of carbohydrates and proteins. Perhaps the most relevant used mixed diets consisting of protein, glucids, and lipids. That study indicates that the rate of absorbtion of a:
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Whole meal (casein + bananas + corn oil) :
Carbohydrate: 49% after 2 hours, 73% after 4 hours
Protein: 53% after 2 hours, 76% after 4 hours
Mean absorbtion of meal: 51% after 2 hours, 75% after 4 hours
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Simple meal (casein + dextrin + corn oil) :
Carbohydrates: 62% after 2 hours, 98% after 4 hours
Protein: 69% after 2 hours, 99% after 4 hours.
Mean absorbtion of the meal: 66% after 2 hours, 99% after 4 hours.
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If you want to go a step beyond normal meals, protein shakes would seem to be a performant thing to take, 2 hours before a 1.5 to 2 hour work-out. However, I have not yet looked into the different composition of various shakes, therefore I cannot condone their use right now, since many of them include elements which should not be part of a diet, such as tryptamines.
I can only reccomend a balanced nutrition. If you feel that you lack definition, the solution lies in reducing your caloric intake. An easy way to do this is to eliminate all or part of your carbohydrate intake (bread, pasta, potatoes, starchy foods) and also watch your lipid intake (fries, fat meats, etc.).