How long should a needle be when giving a subcutaneous injection at a 90-degree angle?

For administering a subcutaneous injection at a 90-degree angle, a needle length of 1/2 inch is ideal for most adults, particularly for those who have a normal body mass index. This length ensures that the medication is delivered into the subcutaneous tissue without reaching the muscle below, which is crucial for the proper absorption of certain medications that are intended to be administered subcutaneously.

When injecting at a 90-degree angle, a shorter needle like 1/2 inch helps to minimize discomfort and the risk of injecting into muscle tissue. Longer needle lengths, such as 1 inch or 2 inches, are generally more suitable for intramuscular injections or for patients with higher body fat where a longer reach is necessary to access the subcutaneous layer effectively. Therefore, using a 1/2 inch needle for subcutaneous injections at this angle aligns with best practices for safety and efficacy.