These needles are made of stainless steel in the form of a tube. The ends are usually sharpened to different bevels according to requirement. The sharp point of the needle tip helps to penetrate the skin easily. The rule is that when the needle is inserted, the bevel must be facing upwards.

The diameter of needle itself is indicated by the gauge of the needle. There are a variety of lengths of needle available for every kind of needle gauge according to requirement. For most common medical use, needle gauges range from seven to thirty three, seven being the largest.  The size that is most commonly used for drawing blood for testing purposes is the twenty one gauges. Sixteen or seventeen number gauge is usually used to make blood donations.

Hypodermic needles are most likely to be used by medical professionals, such as doctors, nurses or paramedics; however they are many a times used by patients themselves. This is usually the case with those patients suffering from diabetes of type one; they require several injections of insulin everyday. Even such patients who suffer from asthma or other such allergies may have to administer medication by using these needles themselves, as they might require the medication at any point of time. Such patients require carrying desensitization needles or carrying the syringes filled with Benadryl or the likes. This would prevent these patients from suffering from an attack or an allergic reaction. These Hypodermic needles are also often used for recreational drug use that is administered by the user intravenously. Earlier on, these needles could be obtained only through prescription; however most countries now allow such needles to be dispensed without prescription.