Mecasermin (Increlex)_Dosage, benefits & legal status
Also known as Increlex, rhIGF-1, recombinant human IGF-1, recombinant human insulin-like growth factor-1, mecasermin [rDNA origin], Myotrophin
IGF-1 made in bacteria with exactly the human sequence, for children whose bodies cannot make it in response to growth hormone. First-year growth rose from 2.8 to 8.0 cm a year, and low blood sugar occurred in 42%.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Mecasermin (Increlex)?
Plain language first. The technical label stays, but it never stands alone.Overview
A few children grow very slowly because their bodies cannot make IGF-1, the hormone growth hormone works through, so growth hormone injections do not help them. Mecasermin replaces the IGF-1 directly: in the studies behind its approval (71 children), average growth went from 2.8 cm a year before treatment to 8.0 cm a year in the first year. The main risk is low blood sugar, seen in 42%, so each dose goes with a meal or snack. It is the approved form of the body's own IGF-1, and the evidence behind it does not apply to IGF-1 LR3 or IGF-1 DES.
Mecasermin is recombinant human IGF-1 made in E. coli: 70 residues with three disulfides (6 to 48, 18 to 61 and 47 to 52), identical in sequence to the endogenous hormone and unmodified, 7649 Da. It activates the type 1 IGF-1 receptor directly, bypassing the growth hormone step that fails in severe primary IGF-1 deficiency, as in growth hormone receptor defects (Laron syndrome). It is the parent of the modified analogs IGF-1 LR3 and IGF-1 DES, and its clinical evidence does not carry over to them.
What it's used for
Twice-daily injections under the skin for children 2 and older with severe primary IGF-1 deficiency, or with a growth hormone gene deletion and antibodies that block growth hormone. It does not replace growth hormone for other growth problems.
How does Mecasermin (Increlex) work?
What it does in the body, and where.Mecasermin supplies IGF-1 itself, the hormone that growth hormone normally makes the body produce.
- 01The broken stepGrowth hormone normally binds its receptor in the liver and other tissues and triggers IGF-1 production. In severe primary IGF-1 deficiency, for example when the growth hormone receptor is faulty (Laron syndrome), that step fails, so giving growth hormone does not raise IGF-1.
- 02Going around itMecasermin is the same 70-amino-acid protein, made in bacteria. It binds the type 1 IGF-1 receptor in target tissues and switches on the signaling that drives growth.
- 03The sugar effectIGF-1 also helps cells take up glucose, fatty acids and amino acids, and its receptor is related to the insulin receptor, so low blood sugar is the main risk and doses go with food. Unbound IGF-1 clears quickly: clearance falls as levels of its binding protein IGFBP-3 rise.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
Growth in primary IGF-1 deficiency
FDA-approved- Human trial71 children in five studies: height velocity 2.8 cm a year before treatment, 8.0 in year 1 (p<0.0001), 5.8 in year 2 and 5.5 in year 3.
- No dataFour of the five studies were open-label and there was no single randomized pivotal trial; approval rested on change within each child.
Long-term treatment
peer-reviewed-human- Human trial76 children treated for up to 12 years at 60 to 120 mcg/kg twice daily: growth rose from 2.8 to 8.0 cm a year in year 1, depended on dose, and stayed above baseline for up to 8 years.
- Human trialLow blood sugar in 49%, injection-site lipohypertrophy in 32% and tonsil or adenoid enlargement in 22%.
ALS
tested-and-failed- Human trial330 patients at 20 centers on 0.05 mg/kg twice daily or placebo for 2 years: no difference in manual muscle testing, tracheostomy-free survival or ALSFRS-R decline.
Preterm infants (IGF-1/IGFBP-3 complex)
tested-and-failed- Human trial121 infants enrolled (61 treated and 60 controls analyzed) on 250 mcg/kg a day by continuous infusion: retinopathy of prematurity was not reduced in occurrence or severity.
- Human trialSevere bronchopulmonary dysplasia 21.3% against 44.9% (p=0.04), a secondary finding in a small trial; fatal or serious adverse events were 19.7% against 11.7%.
- No dataThis used the rinfabate complex given into a vein, not Increlex.
Cancer reports
FDA-approved- RegulatoryPostmarketing reports of malignant tumors in children led to a December 2019 change that widened the cancer contraindication to a history of malignancy and added a warning; the label says any link to treatment is unknown, and tumors were seen more often at higher than recommended doses or with IGF-1 above the normal range.
Mecasermin is often lumped together with IGF-1 LR3 and IGF-1 DES under the name 'IGF-1'; it is the unmodified 70-residue human hormone, while LR3 and DES are altered analogs, and none of mecasermin's trial or label data apply to them. Peptide sites often quote an IGF-1 half-life of 12 to 16 hours bound and about 15 minutes free; those figures describe the body's own IGF-1 held by its binding proteins, and the label figure for injected mecasermin is 5.8 hours. Its safety is often summarized as 'malignancy-related warnings'; there is no boxed warning, and active or suspected cancer has been a contraindication since 2005, and a December 2019 change widened it to a history of cancer and added a warning, with the label stating that any link to treatment is unknown. It was approved as an NDA in 2005 but has been BLA 021839 since March 23, 2020, and an orphan-designation record is sometimes cited as its approval record; the approval is Drugs@FDA application 021839, dated August 30, 2005. It is often described as an Ipsen product; Eton Pharmaceuticals bought it in December 2024 and ESTEVE holds the rights outside the US, though Ipsen and Eton labels both still appear on DailyMed and Drugs@FDA still lists Ipsen as the applicant. Mecasermin rinfabate (Iplex) is a different product, IGF-1 bound to IGFBP-3 and given once daily, and it left the market in 2007 under a patent settlement, not for safety. Bioavailability 'close to 100%' was measured in healthy subjects and was not determined in children with the condition.
The published record
Papers and trials about Mecasermin (Increlex)
93 papers tagged human · 38 not reviews or lab · 1 clinical trial publications
37 registered trials · 20 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Mecasermin (Increlex)
Evidence
FDA-approved
Category
Growth hormone
Common vial
Varies
Half-life
About 5.8 hours
How much, and do you cycle it?
The range, and whether you take breaks.0.04 to 0.08 mg/kg twice daily to start, up to 0.12 mg/kg twice daily (label), twice a day, with a meal or snack. Twice daily, long term, while the growth plates are open FDA label
Given long term for growth, and closed growth plates are a contraindication. The label data cover a mean of 3.9 years, and the 2007 paper followed some children for up to 12 years.
How long does it stay in the body?
The half-life, and where the figure comes from.About 5.8 hoursFDA label
Terminal half-life 5.8 hours (coefficient of variation 64%, from 3 subjects aged 12 to 22) in patients with severe primary IGF-1 deficiency after a single 0.12 mg/kg dose under the skin, unchanged since the 2005 label. Levels peak at 2 hours, at 234 ng/mL. Clearance is inversely proportional to IGFBP-3 levels. Bioavailability is close to 100% in healthy subjects but was not determined in patients. The IGF-1 in Iplex, bound to IGFBP-3, had a half-life of 13.4 hours.
Source: Increlex US prescribing information, section 12.3
You can compare this against the whole library to see where it sits.
How is it given?
Dosing context and source notes.Supplied as a ready-made solution, so there is nothing to mix.
Label range: 0.04 up to 0.12 mg/kg per dose. Increlex US prescribing information (DailyMed, Eton Pharmaceuticals), sections 2 and 16
Injected under the skin twice a day, never into a vein, shortly before or after a meal or snack (within about 20 minutes). The starting dose is 0.04 to 0.08 mg/kg (40 to 80 mcg/kg) per dose; if that is well tolerated for at least a week, it goes up by 0.04 mg/kg per dose, to a maximum of 0.12 mg/kg twice daily. Higher doses have not been evaluated. A dose is skipped if the child cannot eat, and a missed dose is never made up by increasing a later one. Blood sugar before meals is checked until a well-tolerated dose is found, and the dose is lowered if low blood sugar occurs despite enough food. Sites are rotated among the upper arm, thigh, buttock and abdomen. The label gives no kidney or liver adjustment. Supplied as a ready-made 40 mg/4 mL (10 mg/mL) solution in a multiple-dose glass vial preserved with benzyl alcohol (9 mg/mL), so nothing is mixed; vials are refrigerated at 2 to 8°C, not frozen, kept from light and used within 30 days of first opening. The dose is set by body weight and stepped up by tolerance, so the calculator cannot draw one.
How do you store it?
Before mixing, and after.Supplied ready to use. Store it as the label says.
Mecasermin (Increlex) comes as a ready-made solution, prefilled syringe or ampoule, not a powder, so there is no mixing step and no reconstitution clock. Keep it in its original pack and follow the storage and expiry dates on the label. Many ready-made peptide medicines are kept in the fridge and must not be frozen; a few are made to be stored at room temperature.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 27% charged residues, 46% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- Closed growth plates (epiphyses)
- Active cancer or a history of cancer (active or suspected cancer since 2005; history of cancer added December 2019)
- Allergy to mecasermin or any inactive ingredient
- Never injected into a vein
- Not recommended in infants: it contains benzyl alcohol, and medicines preserved with it have caused gasping syndrome and death in newborns and infants; not established under age 2
Stop and get help
- A seizure or loss of consciousness after a dose: severe low blood sugar
- Hives, swelling or trouble breathing, possible anaphylaxis (estimated at 0.3% after approval)
- A new limp or hip or knee pain, or headache with vision changes and vomiting: possible slipped hip growth plate or raised pressure in the skull
Common effects
- Low blood sugar in 42% (30 of 71 children), 5 of them severe and 4 with a seizure or loss of consciousness; the trials were mostly open-label, with no placebo comparison
- Enlarged tonsils in 15% (11 children), mostly in the first 1 to 2 years, with snoring, sleep apnea or fluid in the middle ear
- Fatty lumps at injection sites (lipohypertrophy), bruising, ear infections, snoring, headache, dizziness, seizures, vomiting and joint pain each in 5% or more
- In the 2007 long-term paper, low blood sugar 49% (some also before treatment), injection-site lipohypertrophy 32% and tonsil or adenoid enlargement 22%; raised pressure in the skull in 3 children in the label data
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Mecasermin (Increlex) approved?
And where the numbers on this page come from.Yes. Mecasermin (Increlex) is FDA approved and available on prescription in the United States. It is also approved in the European Union.
- Approval statusFDA-approved
- RouteUnder the skin (twice-daily injection)
- Checked18 October 2026
- Approved outside the USEuropean Union: Authorized in the EU under exceptional circumstances (European Commission decision August 3, 2007), now held by Esteve Pharmaceuticals, S.A., for long-term treatment of growth failure in children and adolescents with severe primary IGF-1 deficiency. Eton states it is approved in 40 territories including the US and EU; dates for the UK, Japan and other countries are not established.This does not change the United States position above.
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesDailyMed, Increlex, Eton Pharmaceuticals (revised October 2025)DailyMed, Increlex, Ipsen Biopharmaceuticals (revised July 2025)Drugs@FDA, application 021839Increlex original US label (2005)Increlex US label, supplement 24 (2019)FDA GSRS protein record, mecasermin (UNII 7GR9I2683O)EMA, Increlex EPAR (EMEA/H/C/000704)Eton Pharmaceuticals Form 8-K (December 2024)ESTEVE, Increlex license agreement (April 1, 2025)Insmed Form 8-K, exhibit 99.1 (April 25, 2007)Iplex (mecasermin rinfabate) US label (2005)Chernausek SD et al., Journal of Clinical Endocrinology and Metabolism 2007;92:902-910Sorenson EJ et al., Neurology 2008;71:1770-1775Ley D et al., Journal of Pediatrics 2019;206:56-65.e8
What has happened recently
Genentech held the original IGF-1 rights and licensed Increlex to Tercica, Inc. The FDA approved it on August 30, 2005 (application 021839, orphan) for long-term treatment of growth failure in children with severe primary IGF-1 deficiency or growth hormone gene deletion with neutralizing antibodies to growth hormone. The indication now reads pediatric patients 2 years and older, with limits stating it does not replace growth hormone and is not for secondary IGF-1 deficiency. A December 3, 2019 supplement widened the cancer contraindication from active or suspected neoplasia (in place since 2005) to include a history of malignancy, and added a malignant neoplasia warning. It was deemed a BLA, the application type for biologics, on March 23, 2020. Ipsen acquired Tercica in 2008; Eton Pharmaceuticals bought Increlex from Ipsen, closing on December 19, 2024, and markets it in the US, while ESTEVE licensed the rights outside the US on April 1, 2025. In the EU it was authorized under exceptional circumstances, with the European Commission decision on August 3, 2007; Esteve Pharmaceuticals, S.A. now holds the authorization, the EU orphan designation was withdrawn in August 2017 at the end of market exclusivity, and a 2013 shortage that hit both the EU and the US, caused by manufacturing problems at drug-substance maker Lonza, has been resolved. A sister product, mecasermin rinfabate (Iplex, Insmed), IGF-1 bound to its binding protein IGFBP-3, was approved on December 12, 2005 and taken off the market for primary IGF-1 deficiency under a March 2007 patent settlement with Tercica and Genentech, not for safety; it is listed as discontinued.
You can compare this against the whole library, or read how to check a seller.
What else is like Mecasermin (Increlex)?
Others in Muscle building, side by side.If you're weighing Mecasermin (Increlex), it's worth reading Mifomelatide, Tesamorelin, and Ipamorelin in the same class.
IGF-1 made in bacteria with exactly the human sequence, for children whose bodies cannot make it in response to growth hormone. First-year growth rose from 2.8 to 8.0 cm a year, and low blood sugar occurred in 42%.
- Dose
- 0.04 to 0.08 mg/kg twice daily to start, up to 0.12 mg/kg twice daily (label)
- How often
- Twice a day, with a meal or snack
An experimental daily shot that switches off two appetite-suppressing receptors, the reverse of setmelanotide.
- Dose
- 12.5 to 50 mg daily (phase 2 doses)
- How often
- Daily
An approved shot proven to shrink stubborn belly fat.
- Dose
- 1.28 up to 2 mg per day, depending on which product you have
- How often
- Daily
A gentle shot that nudges your body to release its own growth hormone.
- Dose
- 0.2 up to 0.3 mg per dose (start low, increase slowly)
- How often
- Daily, often at night
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
Sources
- DailyMed, Increlex, Eton Pharmaceuticals (revised October 2025)(2025)BLA021839; marketing start April 16, 2025; 0.04 to 0.12 mg/kg twice daily; slipped capital femoral epiphysis warning dated May 2025.
- DailyMed, Increlex, Ipsen Biopharmaceuticals (revised July 2025)(2025)Indication and limits of use; low blood sugar in 42% of 71; half-life 5.8 hours; 70 residues, 7649 Da, three disulfides, made in E. coli; growth 2.8 to 8.0 cm a year.
- Drugs@FDA, application 021839(2026)Approved August 30, 2005 with orphan status; deemed a BLA March 23, 2020; supplement history.
- Increlex original US label (2005)(2005)Original indication; not studied under age 2 or in adults; made for Tercica, Inc.; 5.8-hour half-life; no boxed warning; active or suspected neoplasia already contraindicated.
- Increlex US label, supplement 24 (2019)(2019)Malignant neoplasia contraindication and warning dated December 2019; indication for patients 2 years and older.
- FDA GSRS protein record, mecasermin (UNII 7GR9I2683O)(2026)70-residue chain, the mature human IGF-1 sequence; disulfides 6 to 48, 18 to 61 and 47 to 52.
- EMA, Increlex EPAR (EMEA/H/C/000704)(2026)Authorized under exceptional circumstances; European Commission decision August 3, 2007; holder Esteve Pharmaceuticals, S.A.; orphan designation withdrawn August 2017.
- Eton Pharmaceuticals Form 8-K (December 2024)(2024)Purchase of Increlex from Ipsen closed December 19, 2024: $22.5 million at closing plus $8.7 million of inventory.
- ESTEVE, Increlex license agreement (April 1, 2025)(2025)License and supply agreement with Eton for global rights excluding the US.
- Insmed Form 8-K, exhibit 99.1 (April 25, 2007)(2007)Patent settlement with Tercica and Genentech: Iplex withdrawn for primary IGF-1 deficiency and short-stature development stopped.
- Iplex (mecasermin rinfabate) US label (2005)(2005)1:1 complex with IGFBP-3, 36,381 Da; once daily at 0.5 to 2 mg/kg; IGF-1 half-life 13.4 hours.
- Chernausek SD et al., Journal of Clinical Endocrinology and Metabolism 2007;92:902-910(2007)76 children treated for up to 12 years at 60 to 120 mcg/kg twice daily: growth 2.8 to 8.0 cm a year in year 1 (p<0.0001); low blood sugar 49%.
- Sorenson EJ et al., Neurology 2008;71:1770-1775(2008)330 patients with ALS on 0.05 mg/kg twice daily or placebo for 2 years: no benefit on muscle strength, tracheostomy-free survival or ALSFRS-R.
- Ley D et al., Journal of Pediatrics 2019;206:56-65.e8(2019)IGF-1/IGFBP-3 complex in preterm infants: retinopathy not reduced; severe bronchopulmonary dysplasia 21.3% against 44.9% (p=0.04).
Beyond these, 110 records are indexed. Browse the records