It depends on needle length and body type
There isn’t one universally correct angle for every subcutaneous injection. A 90-degree angle (straight in) is standard for shorter needles (commonly 4-6mm) and for most people with average subcutaneous fat. A 45-degree angle is more often used with longer needles, or for people with less subcutaneous tissue, to reduce the risk of an intramuscular injection rather than a subcutaneous one.
Why the distinction matters
Subcutaneous injections are absorbed differently than intramuscular ones, generally more slowly and steadily, which is part of how these drugs are designed to work. Injecting too deep changes that absorption pattern.
The pinch technique
Pinching a fold of skin before injecting, regardless of angle, lifts the subcutaneous layer away from the muscle underneath, which is one of the more reliable ways to keep a shorter needle genuinely subcutaneous at a 90-degree angle.
What to check on your specific pen or syringe
The needle length that comes with a specific pen or syringe is usually printed on the packaging. Checking it, rather than assuming, is the simplest way to know which angle guidance actually applies to what you’re using.
When in doubt
If it’s unclear which angle applies to a specific device, the pinch technique combined with a 90-degree angle at a fleshy site (like the abdomen) is a commonly used, straightforward default for shorter needles.