I have very thick excessive oily skin. How frequently we can do glycolic 50% peeling at home?

Weekly. A 50% glycolic peel is fairly safe to perform weekly. Be cautious not to leave the agent in contact with the skin too long as burning and flakiness/peeling of the skin may result.
GLYCOLIC PEELS. 30% glycolic acid peels can often be done every week or every two weeks depening on how the first one has reacted and how oily the skin is. I don't think i would try the 50% peel at first.
Why choose this? Although i understand that you may be getting some improvement with these home peels, you really just making it look better for a short period of time. I would suggest seeing a facial skin expert (plastic surgeon or dermatologist) with an interest in this particular issue. We can do a great deal to decrease oil production with topical & even low dose oral medications in addition to peels, etc.
Glycolic peels. This can be a very potent peel with serious side effects if not performed properly. I would not do this without supervision. Gerally speaking we will perform a series of six treatments and then monitor response. Strict sun exposure is recommended.