Your capital is guaranteed, so you will not lose money in absolute terms if it stays in a deposit account. 

However, in real terms, inflation can have an impact. Prices rise over time so what you can buy in five, ten, twenty years with that capital is likely to be less than you can buy with it today. Of course, your capital earns interest which can help to mitigate any inflationary effects, but sometimes that interest payment will be higher than the rate of inflation and sometimes that interest will be lower.