Dreborg S, et al. - Researchers herein discussed suitable needle lengths of epinephrine autoinjectors (EAIs) based on ultrasound measurements related to weight. A high risk of periosteal/intraosseous penetration in children and subcutaneous injections in overweight and obese adults was reported with the use of common high pressure EAIs (HPEAIs). With low pressure EAIs (LPEAIs), some risk of subcutaneous injection in adults was reported. Notably, no risk of periosteal/intraosseous injection but a high risk of subcutaneous deposit was noted with HPEAIs 0.1 mg epinephrine and shorter needle. For use in adult, over-weight/obese patients, HPEAIs and LPEAIs should have longer needles.