Firstly, if by regional, you mean amateur, I doubt they test you guys. Those tests are very expensive and need to be done by 2 independant labs. Currently there is only one in SA. At least, there was. Whether it's still certified is another thing.
Then, why do you want to lose weight? Do you want to drop 1, maybe 2 weight classes?
What is your current weight and BF%?
If you're 90kg with 15% BF, you can easily cut fat and then the last few kg's as a water weight cut for weigh in. You should have enough contacts to be helped with a weight cut for weigh in. If you've never done one before, it's hectic and your body needs to be conditioned to handle the massive water loss and immediate rehydration with no, it very little loss of performance. NB! Amateurs attempting pro level cuts have died
I have seen fighters cut from Welterweight to weigh in at LW. To me the whole weight cut makes a farce of divisions as you rarely get true weight class representation. Only HW where you don't need to cut.
Bit, I digress. That's a debate for another day and another forum.
If you're already lean AF, it means you need to cut muscle, which, is harder than what you think and more importantly, it's going to negatively affect stamina and strength.
However, without knowing what your beginning weight, bf% and goals etc are, it's difficult to give advice.
Edit/Addendum: by tests I mean for PED's. They may well do a simple urine test for things like cocaine, amphetamine etc.
PED testing requires more intense use of equipment like Mass Spectrometers which are fun to work with but moer expensive.
Good judgement comes from experience.
Experience comes from bad judgement.
