I washed off the VI Peel applied about 15 minutes shy of the 4 hours. Will this greatly reduce the effect of the treatment?

You should be fine.  It will take about 2 days for you to peel so don't get discouraged but washing it off 15 minutes earlier than normal should not affect it.  Best of luck!  

thank you for your question. it is recommended to leave the peel on for 4 to 6 hours. 15 min shy of 4 hours shouldn't make a huge difference. just be sure to follow the protocol correctly for the next week.

Great question! Following the package instructions is always best, but in practice I have seen some variation due to lifestyle/work schedules. I have not appreciated any complications. The results will likely also not be compromised. You should note peeling starting around day 3. Post some followup before/after pictures.