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Increlex

mecasermin
Used for IGF-1 Deficiency
Used for IGF-1 Deficiency

Increlex (mecasermin) is a recombinant insulin-like growth factor-1 (IGF-1). It treats children 2 years and older who are short for their age as a result of certain genetic conditions. These children have either severe primary IGF-1 deficiency or growth hormone (GH) deletion with antibodies that attack GH. Increlex (mecasermin) is given as an injection under the skin twice a day. Dosing is based on how much your child weighs, how well the medication is working, and whether there are side effects. Side effects can include headache and bruising at the injection site. It can also put your child at risk for low blood sugar (hypoglycemia).

Last reviewed on February 11, 2025
basics-icon

What is Increlex (mecasermin)?

What is Increlex (mecasermin) used for?

How Increlex (mecasermin) works

Increlex (mecasermin) is a recombinant insulin-like growth factor-1 (IGF-1). It's a lab-made version of the natural hormone your body makes called IGF-1. This hormone is important for your bones and tissues to grow properly.

Children with primary IGF-1 deficiency or GH gene deletion have very low levels of IGF-1. Because they don't have enough IGF-1 in the body, these children can't grow properly. Increlex (mecasermin) helps raise their IGF-1 levels so that their growth can improve.

Drug Facts

Common BrandsIncrelex
Drug ClassInsulin-like growth factor-1 (IGF-1)
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
basics-icon

What are the side effects of Increlex (mecasermin)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Low blood sugar (42%)
  • Swollen tonsils (15%)
At least 5% of children reported the following side effects during clinical studies:
  • Bruising where the medication is injected
  • Thickening of skin where the medication is injected
  • Headache
  • Dizziness
  • Uncontrolled muscle spasms
  • Vomiting
  • Joint pain
  • Pain in the arm or leg
  • Ear infection
  • Ear pain
  • Fluid buildup in the ear
  • Snoring

Other Side Effects

  • Thickening of skin around the face
  • Other reaction where the medication is injected (e.g., irritation, redness, pain, rash)

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Dangerously low blood sugar: feeling faint, shaking, sweating, dizziness, fast heartbeat, nervousness, anxious, confused, irritable, feeling very hungry
  • Serious allergic reaction: hives, rash, itching, dizziness, shaking, flushing, nausea, trouble breathing, chest pain, swelling of the face or mouth
  • High pressure in the brain: changes in vision, headache, nausea, vomiting

Source: DailyMed

The following side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Anxiety

bluish skin color of the fingertips

blurred vision

breathlessness

chest pain

chills

cold sweats

coma

confusion

cool, pale skin

depression

dizziness

fast heartbeat

headache

increased hunger

loss of hearing

nausea

nervousness

nightmares

rapid growth of normal cells of the thymus (no symptoms)

seizures

shakiness

slurred speech

thickening of the skin

unusual tiredness or weakness

Incidence not known

Change in the ability to see colors, especially blue or yellow

cough

difficult or labored breathing

difficulty with swallowing

hives or welts, itching, or skin rash

itching or hives at the injection site

large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs

limp

pain in the hip or knee

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

redness of the skin

tightness in the chest

vomiting

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

Anxiety

arm or leg pain

backache

changes in vision

excessive sweating

extreme weakness

frequent urination

increase in hands and feet size

increased thirst

increased volume of pale, diluted urine

joint pain

stop in menstruation

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Abnormal response of the tympanic membrane to air pressure

difficulty with moving

difficulty with swallowing

ear pain

earache

large, flat, blue or purplish patches in the skin

muffled hearing

muscle pain or stiffness

redness or swelling in the ear

sense of fullness in the ear

snoring

sore throat

voice changing

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

pros-and-cons

Pros and cons of Increlex (mecasermin)

thumbs-up

Pros

Works well to promote growth in children with certain genetic conditions

Can give injection at home

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Cons

Needs to be given as an injection under the skin twice per day

Need to eat food within 20 minutes of the injection

pharmacist-tips

Pharmacist tips for Increlex (mecasermin)

pharmacist
  • Mark your child's appointments on your calendar so they get followed up and examined on time. This makes sure your child is properly monitored while they're taking Increlex (mecasermin).

    • Make sure your child can eat something within 20 minutes either before or after Increlex (mecasermin) gets injected. If they can't eat anything within this time, skip the injection. This is important because Increlex (mecasermin) has a similar effect to insulin and lowers blood sugar. Having food in the stomach around the time of the injection helps prevent the blood sugar from dropping too low.

      • Children should avoid high-risk activities (like exercising and driving) within 2 to 3 hours after each Increlex (mecasermin) injection. This is important because exercise can lower blood sugar levels. This helps prevent your child from getting hurt if they have symptoms of low blood sugar, like shakiness, confusion, or passing out.

        • The care team will show you how to draw up the dose into a syringe and inject Increlex (mecasermin). Be sure to review the instructions before each injection. Ask the care team if you're not sure how to use the medication.

          • Store new, unopened vials of Increlex (mecasermin) in the refrigerator away from light. After using the vial for the first time, place it in the refrigerator for up to 30 days. Write the 30-day expiration date on the vial after you've opened (used) it for the first time.

            • Increlex (mecasermin) comes in vials that contain enough medication for more than one dose. This means that you use the same vial until it runs out of medication or until the vial's been open for 30 days. Throw away the vial after 30 days, even if there's still medication inside.

              • Always check to make sure the medication in the vial is clear and colorless before using it. Don't use it if it's cloudy, discolored, or has particles (solid chunks). Ask your child's prescriber or pharmacist about what to do next.

                • Always use a new needle and syringe for each Increlex (mecasermin) injection. This helps prevent infections and blocked needles. Don't reuse or share needles with other people to avoid spreading infections.

                  • After you've drawn up the dose into a syringe, clean the area where you'll inject the medication with an alcohol swab. Then, inject Increlex (mecasermin) under the skin into the fatty tissue of the upper arm, thigh, buttock, or stomach. Choose a different place to inject that's different from the last to avoid skin irritation.

                    • Right after the injection, throw away used syringes and needles into a sharps container or something made of heavy-duty plastic (e.g., empty milk carton, laundry detergent bottle). This lowers the risk of needle-stick injuries. Don't throw them away in your trash can. Learn more about how to throw away sharps on the FDA's website.

                      More on Increlex (mecasermin) tips

                      faqs

                      Frequently asked questions about Increlex (mecasermin)

                      Is there a generic for Increlex (mecasermin)?
                      No. There isn't a generic version of Increlex (mecasermin) available yet. Currently, Increlex (mecasermin) is a brand-name medication only.
                      Where should you inject Increlex (mecasermin)?
                      Give the Increlex (mecasermin) injection under your child's skin in their upper arm, thigh, buttock, or stomach. To help prevent bruising and skin irritation, use a different spot each time so you don't inject in the same place too often. Don't rub the injection site after you inject the medication. Never inject Increlex (mecasermin) into a muscle or vein.
                      Can Increlex (mecasermin) be used for adults?
                      No. Increlex (mecasermin) is only approved by the FDA for children who are very short due to certain genetic conditions. These include severe primary IGF-1 deficiency or growth hormone (GH) deletion with antibodies (proteins) that attack GH. There are no studies showing that Increlex (mecasermin) is safe or works well in adults.
                      Can Increlex (mecasermin) be used for bodybuilding?
                      No, don't use Increlex (mecasermin) for bodybuilding. The FDA hasn't approved Increlex (mecasermin) for this purpose. And there isn't any evidence proving that Increlex (mecasermin) would be helpful. Increlex (mecasermin) also isn't approved for adults. It should only be used for children who have an IGF-1 or GH deficiency.
                      Does Increlex (mecasermin) treat poor growth from low growth hormone levels?
                      No, Increlex (mecasermin) doesn't treat poor growth from low growth hormone (GH) levels. Increlex (mecasermin) is only used for treating poor growth that happens with low IGF-1 levels. This is because the medication works by raising the level of IGF-1 in the body. Children with low GH levels and children with low IGF-1 levels are both smaller in size than other children their age. But treatment for these growth problems is different. Some medications that treat low GH include somatropin injections, like Omnitrope. Ask your child's prescriber about treatment options for low GH levels.
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                      What are the risks and warnings for Increlex (mecasermin)?

                      Increlex (mecasermin) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

                      risk-warning

                      Low blood sugar (hypoglycemia)

                      • Risk factors: Younger-aged children | Changes in diet or exercise | Taking other medications that lower blood sugar | Change in dose of Increlex (mecasermin) | Taking more Increlex (mecasermin) than prescribed | Not eating within 20 minutes of taking Increlex (mecasermin) | High-risk activities within 2 to 3 hours of taking Increlex (mecasermin)

                        Increlex (mecasermin) can cause dangerously low blood sugar (hypoglycemia), which can be life-threatening. Low blood sugar is more likely to happen when your child is just starting Increlex (mecasermin) and when the dose is changing a lot to reach a stable dose.

                        To lower the risk for hypoglycemia, your child must eat a meal or snack 20 minutes before or 20 minutes after they get their Increlex (mecasermin) injection. If they can't eat within this time frame, then they should skip the dose. Pay close attention for young children because they might not eat as consistently as older children.

                        Children should avoid high-risk activities (like exercising and driving) within 2 to 3 hours after the injection. This helps prevent accidents or injuries from happening if they have symptoms of low blood sugar, including shakiness, sweating, confusion, or passing out.

                        Make sure you and your child, if old enough, know how to recognize and treat low blood sugar before treatment starts. It's best to always have some form of fast-acting sugar (e.g., glucose tablets, hard candy, fruit juice) with you during treatment. This is helpful when you need to get the blood sugar up fast if it becomes too low. Call 911 right away if your child's blood sugar continues to be low.

                        risk-warning

                        Allergic reaction

                        It's possible to have an allergic reaction to Increlex (mecasermin). These reactions can include widespread hives, swelling of the face or mouth, trouble breathing, and anaphylaxis. Get medical help right away if an allergic reaction to Increlex (mecasermin) happens.

                        risk-warning

                        High pressure in the brain

                        Some children who took Increlex (mecasermin) have developed high pressure in the brain. High pressure in the brain can lead to changes in vision, headache, nausea, and vomiting. It can also lead to an eye problem called papilledema (swelling in the eye).

                        Your child will need to get their eyes checked for papilledema before they start taking Increlex (mecasermin) and also throughout treatment. Tell your child's care team right away if your child has any signs or symptoms of high pressure in the brain, such as blurry vision, changes in vision, headache every day, or nausea, while they're taking this medication.

                        risk-warning

                        Lymph tissues (tonsils and adenoids) that grow too big

                        During treatment with Increlex (mecasermin), some children had tonsils and adenoids, which are part of the immune system, that grew too big. This has caused problems with sleeping, such as sleep apnea and snoring. It's also sometimes caused fluid buildup in the ear. During follow-up visits, the care team will check your child's tonsils and adenoids to make sure they're a normal size.

                        risk-warning

                        Hip problems

                        Since Increlex (mecasermin) stimulates growth in children, it can cause a hip problem known as slipped capital femoral epiphysis. This happens when the thigh bone slips out of the socket. It can happen in children who are growing very fast. Contact your child's prescriber if your child has a limp or complains of hip or knee pain during treatment with Increlex (mecasermin). These can be signs of hip problems.

                        risk-warning

                        Worsening curving of the spine (scoliosis)

                        • Risk factors: Scoliosis

                          If your child has scoliosis, Increlex (mecasermin) can make it worse because the medication makes them grow faster. Your child's care team will check for signs that the scoliosis is getting worse at follow-up visits. These signs can include an uneven waist or shoulders or the body leaning to one side.

                          risk-warning

                          Risk of cancer

                          • Risk factors: Taking Increlex (mecasermin) at higher-than-recommended doses | Taking Increlex (mecasermin) at doses that produced too much IGF-1 | Other medical conditions that raise the risk for cancer

                            Some children who took Increlex (mecasermin) have developed cancer. But it's not clear whether Increlex (mecasermin) caused the cancer. Many of these children also had other risk factors for cancer or took Increlex (mecasermin) at higher-than-recommended doses. Your child can't take Increlex (mecasermin) if they have cancer now or had it in the past because of this risk. Talk to your child's prescriber if you're worried about this risk. Ask them about your child's risk for cancer.

                            dosage

                            Increlex (mecasermin) dosage forms

                            Typical dosing for Increlex (mecasermin)

                            Increlex (mecasermin) is given as an injection under the skin either in the upper arm, thigh, buttock, or stomach. Only give the injection if your child can eat a meal or snack 20 minutes before or 20 minutes after the shot.

                            The dose is based on your child's weight. The typical starting dose is 0.04 mg/kg to 0.08 mg/kg injected under the skin twice a day. Your child's prescriber might slowly raise the dose up to a maximum of 0.12 mg/kg twice a day as long as there aren't side effects.

                            interactions

                            Interactions between Increlex (mecasermin) and other drugs

                            Increlex (mecasermin) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Increlex (mecasermin). Please note that only the generic name of each medication is listed below.

                            Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

                            contraindications-icon

                            Increlex (mecasermin) contraindications

                            Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Increlex (mecasermin) will not be safe for you to take.
                            • Closed growth plate (when cartilage at the end of a long bone hardens into bone; a sign that the bone is done growing)

                            • Currently have or have had cancer

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                            References

                            Best studies we found

                            American Diabetes Association. (n.d.). Blood glucose and exercise.

                            Anderson, L. J., et al. (2018). Use of growth hormone, IGF-I, and insulin for anabolic purpose: Pharmacological basis, methods of detection, and adverse effects. Molecular and Cellular Endocrinology.

                            Chen, J. J. (2024). Papilledema. Merck Manual Consumer Version.

                            View All References (14)

                            Child Growth Foundation. (n.d.). Primary IGF-1 deficiency.

                            Cogan, J. D., et al. (2006). GH1 gene deletions and IGHD type 1A. Pediatric Endocrinology Reviews.

                            ENThealth. (2019). Tonsils and adenoids. American Academy of Otolaryngology-Head and Neck Surgery Foundation. 

                            Ipsen Biopharmaceuticals, Inc. (2019). Patient information: Increlex® (EENK-RUH-LEX) (mecasermin) injection for subcutaneous use.

                            Ipsen Biopharmaceuticals, Inc. (2024). Increlex- mecasermin injection, solution [package insert]. DailyMed.

                            MedlinePlus. (2024). IGF-1 (insulin-like growth factor 1) test.

                            National Cancer Institute. (2024). Cancer in children and adolescents.

                            National Eye Institute. (2024). Idiopathic intracranial hypertension.

                            National Organization for Rare Disorders. (2016). Growth hormone deficiency.

                            Nemours KidsHealth. (2019). Growth plates.

                            OrthoInfo. (2020). Slipped capital femoral epiphysis.

                            Silberstein, S. D. (2025). Idiopathic intracranial hypertension. Merck Manual Consumer Version.

                            U.S. Food and Drug Administration. (2021). Safely using sharps (needles and syringes) at home, at work and on travel.

                            You and Your Hormones. (2021). Insulin.

                            GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.
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