Yes but 20 effective injections is 23. The first three injections are ineffective according to Pounds and INches. I think that's where a lot of people get confused. Heres what P and I says: We distinguish between the first three injections, which we call “non-effective” as far as the loss of weight isconcerned, and the subsequent injections given while the patient is dieting, which we call “effective”. So 20 effective injections is 23 injections total.