The ability to carryover a business loss to other tax years can be different depending on the type of entity.
If you are a sole proprietor, filing Schedule C on your Form 1040, a business loss reduces your other taxable income (wages, retirement, social security, other income) in the same tax year. You could have a carryback/carryover if you had an actual Net Operating Loss (NOL) (negative taxable income before considering personal exemptions). If you have a NOL in a tax year, you must carry back the entire amount of the loss to 2 prior tax years, and then carry forward any remaining loss up to 20 years after the current tax year. You can also choose not to carry back the loss and only carry it forward.
If your business is a partnership or S Corporation, the rules regarding net losses can be more complicated. The allowed loss is affected by your basis in the partnership or S Corp, the amount of investment you have "at-risk", and the amount of distributions you have taken to date.
In any case, you will not lose the deductions in a tax year where you had a loss. A sole proprietor can use those losses by either carrying the loss back or forward as noted above. Any suspended losses incurred by an S Corp or Partnership may be limited or suspended but can be deducted in full when the you sell your interest in the business.
