Lets say you planned to use 500mg/week of a steroid with a 14 day half life and you want this to be an 8 week cycle.
If you did a straight cycle of 500mg/week, it would take you over a month of weekly injections of 500mg/week to even begin to near the peak blood plasma level. That’s almost half of your cycle you spent waiting to reap the full benefits of the dose of the AAS.
Now, if you front end loaded it by injecting 1000mg on the first day, you would get close to this peak around the three week mark.
Furthermore, if you injected 1500mg on the first day and then fell to your regular 500mg/week schedule after that, you would hit close to your blood plasma peak 24 hrs after your second shot on day 7.
Check out the chart. The values are amounts released on that particular day.
day/no load/2x load/3x load
This is all based on the theoretical half life concept. For simpicity, injection soreness, volume, practicality and other problems assiciated with injections were not considered.
Strictly from the mathematical side, front end loading is most beneficial with "long acting" androgens and it's benefit decreases with AAS that have less lipophilic esters. Likewise, the benefit is greatest with shorter cycles, and becomes less significant with longer one's.