Of note, more than one-quarter of thigh injections (27.1%) were administered without a lifted skin-fold and 76% were administered at an angle of 90° to the skin. Similarly, only 49% of people who injected into the arm were injecting into a lifted skin-fold, with 66% injecting directly at 90°. If a lifted skin-fold is used for injections, virtually all injections will enter at 90°. Finally, 55% of subjects who were injecting into their buttocks were using a lifted skin-fold; 26% of all injections into the buttock were given at an angle of 45°.
Participants who pinched their skin to create a skin-fold were asked when they released the skin-fold. Most (54%) said they released it before the end of the injection or just after the injection, instead of holding it for at least 5 s after completion of the injection. Nearly 20% of participants are using their entire hand to lift the skin-fold.
Twenty-one percent of participants admitted injecting into the same site for an entire day, or even over a few days. Twelve percent chose the injection site based on pain criteria (i.e. they injected themselves in sites that would hurt the least). Thirty-two percent of participants admitted to having no specific injection routine.
Participants were presented with four alternative surface area diagrams and asked which represented the size of the area into which they injected. The largest was the size of a post card, the next largest was the size of a playing card, followed by an area the size of a credit card, with the smallest being the size of a postage stamp. Eighty-two percent of participants stated that abdominal injections were made into areas corresponding to the two largest sizes.
An association was found between the presence of abdominal lipohypertrophy and the size of the injecting area (Table 9). Abdominal lipohypertrophy seemed to be more frequent in those using the two smaller injecting size areas and less frequent in those using the larger sizes. Ninety-one percent of participants reported that they rotate within the same site and 93% rotate from left to right sides of the body. Seventy-nine percent of participants injecting into their thigh used the two larger injection areas for injections in the thigh, compared with 52% and 32% for those who inject into the buttocks and arm, respectively