I get lumps and bumps where I inject insulin. Is there something wrong?

The lumps you describe are fat deposits that may occur when insulin is injected into the same general area on a repeated basis.

These lumps can delay the absorption of insulin and cause unwanted glucose fluctuations that trigger low blood sugar, or hypoglycemia.

You should point these areas out to your doctor. In the meantime, you should avoid those areas for injecting to allow time for them to heal.

You should change injection sites to other areas.

Always keep 2 to 5 cm distance between old and new injection site. Something that could be helpful are “injection site templates”.

One easy way to remember to rotate injection sites is to inject on the right side (of the arm, leg, or belly) for any morning and lunch insulin, and on the left side (of the arm, leg, or belly) for the dinner and bedtime insulin.

Insulin Safety

For many people with diabetes, injecting two types of insulin is a daily requirement. Giving yourself your injections can become so much a part of your routine that you can do it without thinking — which can lead to errors.

To increase insulin safety and avoid taking the wrong insulin:

  • Pause and double-check that you’re taking the correct insulin.
  • Label insulin vials or pens with different-colored tape, so that you can differentiate between them. For example, use red tape for short-acting insulin and yellow tape for long-acting insulin.

If you accidentally give yourself the wrong insulin:

  • Call your local emergency number.
  • Test your blood sugar frequently until help arrives. Eat or drink a fast-acting carbohydrate to maintain a blood sugar within your goal range.

In preparation for such issues, it’s a good idea to always carry a simple sugar source with you, such as glucose tablets, juice, regular soda or hard candy.

Injecting Insulin

How to inject insulin?

The concentration (strength) of insulin is measured in USP Insulin Units and USP Insulin Human Units and is usually expressed in terms such as U-100 insulin.

It is important to follow any instructions from your doctor about the careful selection and rotation of injection sites on your body.

To prepare your insulin injection correctly:

  • Wash your hands with soap and water.
  • Before every injection you should shoot 1 to 2 units into the air until you see a drop on the tip of the needle. This way  you make sure that the pen is functioning. In case there is no insulin coming out of the pen, it might be that the cartridge is empty, the needle is clogged or that the piston position is not correct.
  • If you are using intermediate insulin, mix the insulin by rolling the pen slowly  between your hands at least 20 times. Never shake the pen vigorously (hard).
  • Do not use the insulin if it looks lumpy or grainy, seems unusually thick or seems to be even a little discolored.

Do not use the insulin if it contains crystals.

Regular insulin (short-acting) should be used only if it is clear and colorless

  • Adjust the right dose of insulin with the dosage knob
  • Chose the optimal injection site: abdomen, outer thighs or buttocks.

At the abdomen the insulin ill be absorbed the fastest. The area around the navel (around 8 cm surrounding the navel) should not be used. Insulin that is injected into the thigh or the buttocks will be absorbed slower. Talk to your doctor to see which injection site to use.

  • Avoid areas with scarring (old surgery sites) or moles because the tough tissue may not absorb insulin well
  • Gently pinch your skin with your free hand to avoid any damage of the vessels or muscles.
  • Do not inject insulin through clothes.
  • Always inject the length of the needle either straight or slightly diagonal into fatty tissue.
  • Do not pull the needle instantly out. Leave it at least 10 seconds in to make sure that the insulin is distributed.
  • After each injection change the injection site.
  • Use the needle of the pen only once. If you use the needle too often it can cause tissue changes which will prevent the absorption of insulin.

Leaving an insulin needle attached to an insulin pen can lead to unintentional air entering into the insulin pen. If unintentional air enters into the insulin pen, it can contribute to air bubbles accumulating within the insulin and pen and ultimately improper dosing of insulin.  It could also lead to insulin contamination.

To make sure that insulin is correctly distributed

  • Use the right needles depending on your fatty tissue. For the optimal injection the length of the needle is important. Needles are available for children, skinny, and normal as well as more corpulent people with diabetes.
  • Always use the same body region at the same time of the day (e.g. morning the abdomen, evening the thigh) otherwise there may occur variations in the blood sugar levels

Changes in dose—your doctor may change the first dose of the day. A change in the first dose of the day might change your blood sugar later in the day or change the amount of insulin you should use in other doses later that day. That is why your doctor should know any time your dose changes, even temporarily, unless you have been told otherwise.

On sick days—when you become sick with a cold, fever, or the flu, you need to take your usual insulin dose, even if you feel too ill to eat. This is especially true if you have nausea, vomiting, or diarrhea. Infection usually increases your need for insulin. Call your doctor for specific instructions. Continue taking your insulin and try to stay on your regular meal plan. However, if you have trouble eating solid food, drink fruit juices, non-diet soft drinks, or clear soups, or eat small amounts of bland foods. A dietitian or your doctor can give you a list of foods and the amounts to use for sick days. Test your blood sugar level at least every 4 hours while you are awake and check your urine for ketones. If ketones are present, call your doctor at once. If you have severe or prolonged vomiting, check with your doctor. Even when you start feeling better, let your doctor know how you are doing.


Store in the refrigerator. Do not freeze.

Store your insulin in the refrigerator, in an insulated case or cooler with a freezable gel pack, or use a cooling wallet. Cooling wallets are available through many diabetes supply companies and keep insulin vials, pens and pumps cool at a safe temperature without the need for refrigeration or ice. The wallets have a liner filled with crystals. The liner is immersed in cold water for 10-15 minutes, and placed back into the wallet, along with the insulin. It works by relying on the process of evaporation for cooling, can keep insulin cool for up to 48 hours, and is reusable

Unopened bottles of insulin should be refrigerated until needed and may be used until the printed expiration date on the label. Insulin should never be frozen. Remove the insulin from the refrigerator and allow it to reach room temperature before injecting it.

An insulin bottle in use may be kept at room temperature for up to 1 month. Insulin that has been kept at room temperature for longer than a month should be thrown away.

Storing pre-filled syringes in the refrigerator with the needle pointed up reduces problems that can occur, such as crystals forming in the needle and blocking it up.

Never freeze insulin or expose it to extremely hot temperatures or direct sunlight. Never leave it in your car. Never place it directly on ice or an ice pack.

Throw away insulin that is discolored or contains solid particles.

Remember, after opening a vial of insulin or starting a new insulin pen, the insulin loses its potency and should be thrown away after a certain number of days, depending on the manufacturer’s guidelines. Generally, most vials of insulin are good for 28 days after opening with the exception of Levemir (detemir), which is good for 42 days. Other pens are good for 10, 14, 28 or 42 days. Check the medication insert.

What about insulin pumps?

Heat can make proteins like insulin harden, which increases the potential for infusion set occlusions (blockage). If you live in a hot climate and especially if you work outdoors, you may need to pay closer attention to how the heat can affect your insulin. Using a pump wallet could be another option for people concerned about the effects of heat on their insulin. Also, make sure that the infusion set tubing is tucked in your clothing and not hanging out and exposed to the light and or heat.