compound
Mecasermin
The rare case on this site of a compound with an approval, a manufacturer and a post-marketing registry, covered claim by claim, including the narrowness of what it is licensed for.
- Primary sources Registry records and papers are read at the source, not through summaries. Read the methodology
- Every claim graded Each claim about what a compound does carries an evidence tier and a numbered citation. How grades derive
- Sells nothing No cart, no price, and no product page anywhere on this site. Conflict disclosure
- Corrections logged Errors are fixed and recorded in a permanent public log, never edited away. Corrections log
Mecasermin is the compound on this site that has what almost nothing else here has: a licence. It is sold as Increlex, it has a biologics application number, a named manufacturer and two long-running safety registries, and a doctor can prescribe it.
It is covered here for a specific reason. An engineered version of the same protein, IGF-1 LR3, is sold as a research chemical to adults, and the approval on this page is routinely offered as evidence for that. Reading what the licence actually covers is the fastest way to see why it is not.
The approved use is narrow in every direction that matters: a specific rare deficiency, a specific age group, and an explicit statement on the label that the drug is not a substitute for growth hormone.
| Property | Value | Source |
|---|---|---|
| Category | Recombinant human insulin-like growth factor 1, an approved prescription medicine given by subcutaneous injection | Increlex label, openFDA |
| Brand and application | INCRELEX, biologics licence application BLA021839, Ipsen Biopharmaceuticals, Inc. | Increlex label, openFDA |
| Approved population | Growth failure in pediatric patients 2 years of age and older with severe primary IGF-1 deficiency, or with growth hormone gene deletion who have developed neutralizing antibodies to GH | Increlex label, openFDA |
| What the label rules out | The label states that Increlex is not a substitute to GH for approved GH indications | Increlex label, openFDA |
| Registered trials | 29 records naming mecasermin or recombinant human IGF-1 as an intervention, including four Phase 3 and two long-running safety registries | ClinicalTrials.gov, read 23 August 2026 |
| Anti-doping status | Named on the WADA 2026 Prohibited List at S2.3 by name. Prohibited at all times, and a non-Specified Substance | WADA 2026 Prohibited List |
Not medical advice
This page reports what has been documented about a compound. It is not medical advice, not a diagnosis, not a dosing protocol, and not a recommendation to obtain or use anything described here. Talk to a licensed clinician about anything concerning your health. Read the full disclaimer.
Reviewed against editorial standards Updated
Key takeaways
- This is an approved medicine, which almost nothing else in this catalogue is. It carries a biologics licence application number, a named manufacturer and a label, and it is prescribed.
- The licence covers growth failure in pediatric patients two years of age and older with severe primary IGF-1 deficiency, or with growth hormone gene deletion who have developed neutralizing antibodies to growth hormone. That is the whole of it.
- The label states in its own limitation of use that the drug is not a substitute for growth hormone in approved growth hormone indications. It is a replacement for a missing hormone in people who lack it, not a growth product for people whose levels are normal.
- The registered programme runs to 29 records, including four Phase 3 trials in children with growth failure and two long-running registries with 1,378 and 500 participants. Post-marketing safety registries are a feature of an approved drug and are absent from every research chemical on this site. [Human RCT] [2] [3] [4] [7]
- An engineered analog of this protein, IGF-1 LR3, is sold to adults as a research chemical. It has no registered trial of any kind, and this approval is not evidence about it.
- REGISTERED TRIALS
- 29
- APPROVED AGE FROM
- 2 years
- NUMBERED SOURCES
- 10
- EVIDENCE GRADE
- C
Who researches Mecasermin?
Two groups reach this page and they need opposite things from it.
The first arrived from IGF-1 LR3, having seen this approval cited as support for it. What matters for them is the exact wording of the licence, which is quoted in full below, and the fact that the analog was engineered to behave differently from this molecule.
The second is reading about the drug itself, in which case the registered programme and the registries are the substance. This page does not give clinical guidance and it does not reproduce the label's warnings or contraindications, which belong with a prescriber rather than on a reference site.
What is Mecasermin?
Plain-English version: a laboratory-made copy of a growth hormone the body normally produces in the liver, given as a prescription injection.
Insulin-like growth factor 1 is made mostly in the liver and mostly in response to growth hormone. It is the intermediary through which much of growth hormone's effect on growth is delivered, which is why a child can have normal growth hormone and still fail to grow if this step is missing.
Mecasermin is that protein made recombinantly, with the same 70 amino acid sequence as the human hormone. That distinguishes it from the analog covered elsewhere on this site, which carries a substitution and a thirteen amino acid extension specifically so that it behaves differently in circulation [9].
It is given by subcutaneous injection and it is a prescription medicine. The manufacturer of record on the label is Ipsen Biopharmaceuticals [1].
Recombinant human insulin-like growth factor 1, 70 amino acids · Approximately 7,600 Da
How strong is the evidence, claim by claim?
Every claim area this compound is discussed for gets a row, including the ones with the weakest support. The tier records what the row rests on, and the last column states what that work can and cannot show. Each tier links to its definition on the methodology page.
| Evidence Area | What Has Been Studied | Evidence Level | What It Can and Cannot Show |
|---|---|---|---|
| Growth failure in severe primary IGF-1 deficiency | The approved use, and the one the registered programme was built around. Four Phase 3 records sit in the registry, the largest a completed trial in 137 prepubertal children with growth failure associated with IGF-1 deficiency, alongside a Phase 2/3 of long-term recombinant IGF-1 in 92 participants with growth hormone insensitivity syndrome. The regulatory outcome is on the record: the drug is licensed under BLA021839 for growth failure in pediatric patients two years and older with severe primary IGF-1 deficiency, or with growth hormone gene deletion who have developed neutralizing antibodies to growth hormone [1] [2] [3] | [Human RCT] | The population is the limit. Every part of the licensed indication is narrow: a rare deficiency state, children rather than adults, and a starting age of two years. The label adds its own limitation of use, stating that the drug is not a substitute for growth hormone in approved growth hormone indications. Nothing in this record addresses an adult with normal IGF-1, and one of the four Phase 3 records was terminated. This site did not check whether any of the 29 records has posted results |
| Bone loss in anorexia nervosa | Investigator-led work outside the licence, including a completed study of IGF-1 and bone loss in 148 women with anorexia nervosa and a Phase 3 record in 75 participants on the effects of anorexia nervosa on peak bone mass, both run through Massachusetts General Hospital [4] | [Human RCT] | This is research into a condition the drug is not licensed for, run by a hospital rather than the manufacturer. This site read the registry records rather than any publication, so what these trials found is not established here, and no conclusion about the indication follows |
| Long-term safety in the approved population | Two long-running registries, which exist because the drug is approved. One enrolled 1,378 participants before being terminated and the other, a global registry monitoring long-term safety, was still recruiting when this page was reviewed [5] [6] | [Human open-label] | A registry observes rather than tests, so it does not establish that the drug does anything. What it does establish is a category difference: an approved medicine is followed after licensing, and none of the research chemicals on this site is followed at all. This site did not read the registry outputs and states no findings from them |
Rolled up, that puts Mecasermin at evidence grade C Human data, wrong question . Completed human evidence exists for this compound, and none of it tested the use the compound is sold for. A grade describes the quality of the research, not whether something works and not whether anyone should use it. The derivation is published.
How Mecasermin is thought to work
The mechanism here is the least contested on the site, because the molecule is the hormone rather than an approximation of it.
1. Replacing a hormone that is missing, supplying a hormone the body is not making enough of (established, and the basis of the licence)
Growth hormone drives growth largely by causing the liver to make IGF-1. A child who makes growth hormone normally but cannot make IGF-1 in response to it, or who has developed antibodies that neutralise growth hormone, has a break in that chain that growth hormone itself cannot fix.
Mecasermin supplies the missing step directly. That is why the licensed indication is written the way it is, and it is also why the label states the drug is not a substitute for growth hormone: the two act at different points and are not interchangeable. [Human RCT] [1] [2]
2. Why the analog is a different molecule, the modified version is built to escape the controls this one is subject to (established by the analog's own design description)
Circulating IGF-1 is almost entirely bound to carrier proteins that regulate how much reaches tissue. Mecasermin is the native sequence and is subject to that system in the ordinary way.
IGF-1 LR3 is engineered with low affinity for those carriers and high affinity for the receptor, so it evades the reserve system. The modification is the reason the analog exists, and it is the reason evidence about this molecule does not transfer to it. [Animal] [9] [10]
What we do not know
Whether any of the 29 registered records has posted results. Not checked in this pass.
What the investigator-led trials outside the licence found. The registry records were read; no publication was.
The approval date and regulatory history behind BLA021839.
What the label's own indication and limitation-of-use wording reads as in the label document itself, rather than through the openFDA API this page read it from.
What this evidence can and cannot show
These results come from Human, throughout the registered programme. in Children with severe primary IGF-1 deficiency and with growth hormone insensitivity syndrome., not from people. An animal model is a deliberate simplification: the injury is created on purpose, the animal is young and healthy, the dose is scaled to body weight in a way that does not translate directly, and the outcome is measured at a fixed point rather than lived with. Cell and tissue work is a further step removed, because the concentrations that produce an effect in a dish are often far above anything a body reaches. Mechanism is a reason to run a trial. It is not a substitute for one, and compounds that looked mechanistically convincing have failed in people many times.
Has Mecasermin been tested in humans?
This section is longer here than anywhere else on the site, because there is something to put in it. The registry sweep on 23 August 2026 queried mecasermin, Increlex, mecasermin rinfabate, iPlex, recombinant human IGF-1 and the analog names, then filtered to records whose interventions actually name one of those drugs.
An unfiltered query returns 135 records, because IGF-1 is measured as a biomarker in a great many studies that never administer it. Twenty-nine records survive the filter, and none of them names the analog.
| Study | People | What was done | Result | Evidence level |
|---|---|---|---|---|
| NCT00125164 | 137 | Phase 3 in prepubertal children with growth failure associated with IGF-1 deficiency | Completed | [Human RCT] |
| NCT00330668 | 114 | Phase 3 in children and adolescents with growth failure | Terminated | [Human RCT] |
| NCT00571727 | 92 | Phase 2/3, long-term recombinant IGF-1 in growth hormone insensitivity syndrome | Completed | [Human RCT] |
| NCT00747604 | 1378 | IGFD patient registry, monitoring the approved population after licensing | Terminated | [Human open-label] |
| NCT00903110 | 500 | Global patient registry monitoring long-term safety | Recruiting | [Human open-label] |
| NCT01406444 and NCT01301183 | 148 and 75 | Investigator-led work on bone in anorexia nervosa, outside the licensed indication | Completed | [Human RCT] |
| The remaining 23 records | Various | Phase 1 through Phase 3 across growth disorders, retinopathy of prematurity, Rett syndrome and heart failure | Mixed. Sponsors include Ipsen, Massachusetts General Hospital, the National Institutes of Health and two children's hospitals | [Human RCT] |
Why we are not calling this proof
A large registered programme is not the same as a broad licence. Twenty-nine records exist and the approval covers one rare deficiency in children two years and older, which is what the evidence supported.
None of this is evidence about the engineered analog sold as a research chemical. That molecule was built to behave differently from this one and has no registered trial of its own.
Benefits: what the research shows
The claims table holds what was tested and what the licence covers. This section is the shape of the record as a whole.
The honest bottom line on benefits
This is what a compound looks like when the work has actually been done. There is a programme, a licence, a label that states its own limits, a named manufacturer and post-marketing surveillance. The result of all that is a narrow indication in a small population.
That narrowness is the finding for most readers of this site. A protein with a full development programme behind it earned a licence for children with a severe deficiency of it, and nothing more. An adult with normal levels is outside every part of that.
How long Mecasermin stays in the body
This is the one compound on this site whose pharmacokinetics have been characterised in people to a regulatory standard. The data sit in the approved label alongside the dosing, warnings and monitoring requirements.
This page does not reproduce those figures. They belong to a prescribing document and are used alongside monitoring that a reference site cannot supply, and reproducing them here would turn a record into guidance.
The contrast with the analog is the point worth carrying: mecasermin's behaviour in a person is documented in a regulatory file, and the analog's is documented nowhere.
Characterised, and held in the label rather than reproduced here. [Human RCT] [1]
What is documented about dosing
Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.
Commonly cited protocols (extrapolated, not validated)
Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.
| Study | What was given | Frequency | Duration | Notes |
|---|---|---|---|---|
| Approved label, BLA021839 | Established and set out in the prescribing information | Set out in the prescribing information | Set out in the prescribing information | Not reproduced on this site. It is a prescription medicine used with monitoring, and restating a label turns a record into guidance |
| The registered trials | As specified by each protocol | As specified by each protocol | Up to long-term in the growth hormone insensitivity study | 29 records. This site did not check whether any has posted results |
| IGF-1 LR3, the analog | Nothing documented | Nothing documented | Nothing documented | A different molecule with no registered trial. Figures do not transfer in either direction |
Commonly cited protocols (extrapolated, not validated) for this molecule are rare, because it is a prescription medicine rather than something sold as a research chemical. Where such figures circulate they are generally attached to the analog instead.
The reason this page withholds the label figures is not that they are unavailable. It is that they come with monitoring, and a number lifted out of a prescribing document and put on a reference page has lost the thing that made it usable.
Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.
Main routes people compare, and what each source class actually reported, are set out on the documented protocols page.
Reported effects and what has been measured
What an approval means here
This compound has been through a regulatory review and carries an approved label, which sets out its warnings, its monitoring requirements and the circumstances in which it is not to be used. Two long-running registries follow the approved population after licensing.
This page does not reproduce the label's warnings or the circumstances it rules out. Those belong with a prescriber, and this site's editorial standards do not permit a reference page to publish them. [Human RCT] [1] [5] [6]
What the record does not cover
The registered programme studied children with a severe deficiency. It did not study adults with normal IGF-1 taking the protein for growth or performance, so nothing in this record describes what that does.
Anyone whose question is about that use is asking about a population the evidence does not include, and about a molecule that in most cases is the analog rather than this one. [Human RCT] [2]
What has been measured about Mecasermin, and what has never been studied
Talk to a licensed clinician about anything concerning your health.
Sourcing and quality
What a credible product should show
This is a prescription medicine obtained through a pharmacy against a prescription. It is manufactured under a biologics licence with a defined identity and a regulatory file behind it.
Anything offered for sale outside that route under this name, or under the name of the analog, is not the licensed product, whatever the label says.
Red flags
This approval cited on a page selling the engineered analog. The licence covers the unmodified protein in children with a severe deficiency.
The indication described loosely as growth or growth hormone deficiency. The label names severe primary IGF-1 deficiency and growth hormone gene deletion with neutralising antibodies, and separately states the drug is not a substitute for growth hormone.
A trial count for the analog that is really this compound's 29 records.
Will it show on a drug test?
Named on the WADA 2026 Prohibited List at section S2.3, growth factors and growth factor modulators, in the entry reading insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues. It is named by name.
Prohibited at all times, in and out of competition. The class carries no permitted window.
Non-Specified, which is the category without the reduced-sanction route that a Specified Substance can qualify for. A prescription does not change the list; an athlete with a genuine clinical need takes that to the therapeutic use exemption process.
Storage
Storage conditions are part of the approved prescribing information and are supplied with the product. They are not restated here.
Regulatory status, as of 23 August 2026
| Body | Position | Date | Document |
|---|---|---|---|
| FDA | Approved. Biologics licence application BLA021839, brand INCRELEX, manufacturer Ipsen Biopharmaceuticals, Inc., route subcutaneous | Label read 23 August 2026 | openFDA drug label API |
| FDA | Indication: growth failure in pediatric patients 2 years of age and older with severe primary IGF-1 deficiency, or with growth hormone gene deletion who have developed neutralizing antibodies to GH | Label read 23 August 2026 | Increlex prescribing information |
| FDA | Limitation of use, quoted: INCRELEX is not a substitute to GH for approved GH indications | Label read 23 August 2026 | Increlex prescribing information |
| WADA | Named at S2.3 by name, in the entry covering insulin-like growth factor 1 and mecasermin and their analogues. Prohibited at all times. Non-Specified Substance | 2026 list, read 23 August 2026 | WADA 2026 Prohibited List |
This is the only section of its kind on the site, because it is the only compound here with an approval to report. The three FDA rows are quoted from the label rather than summarised, because the exact wording is what distinguishes this compound's evidence from the analog's marketing.
The label was read through the openFDA drug label API rather than from the label document itself. That is recorded as an open item, and the indication wording should be checked against the document before it is relied on.
This section is dated and re-checked on review. It records agency actions and their documents, not evidence about an effect, and carries no evidence tier.
Mecasermin compared with other performance peptides
| Compound | Evidence grade | What the human record covers | Read more |
|---|---|---|---|
| IGF-1 LR3 | Graded on its own page | The engineered analog sold as a research chemical, with no registered trial and a 2025 study reporting no growth promotion in the animals it was given to | /peptides/igf-1-lr3/ |
| Growth hormone | Not covered as a compound on this site | Acts at an earlier point in the same chain. The label states this drug is not a substitute for it | Described in the mechanism section above |
| Follistatin-344 and ACE-031 | Graded on the performance group page | Other compounds sold for muscle growth, with separate and unrelated evidence bases | /peptides/groups/performance/ |
The comparison this page exists for is with the analog. One molecule earned a licence for a rare childhood deficiency after a full programme; the other was engineered from it and sold to adults with no programme at all.
The growth hormone row is the label's own distinction rather than this site's. It matters because the two are frequently discussed as interchangeable and the prescribing information says plainly that they are not.
What Mecasermin typically costs
Frequently asked questions
Is mecasermin approved?
Yes. It is licensed as INCRELEX under biologics licence application BLA021839, manufactured by Ipsen Biopharmaceuticals, and given by subcutaneous injection.
What exactly is it approved for?
Growth failure in pediatric patients two years of age and older with severe primary IGF-1 deficiency, or with growth hormone gene deletion who have developed neutralizing antibodies to growth hormone. That is the entire licensed indication.
Is it approved for adults?
The licensed indication names pediatric patients two years of age and older. Nothing in the registered programme addresses an adult with normal IGF-1.
Is it a growth hormone substitute?
No, and the label says so in its own limitation of use: INCRELEX is not a substitute to GH for approved GH indications. The two act at different points in the same chain.
How many trials has it been in?
Twenty-nine registry records name mecasermin or recombinant human IGF-1 as an intervention, including four Phase 3 trials and two long-running post-marketing registries enrolling 1,378 and 500 participants.
Is it the same as IGF-1 LR3?
No. This is the native 70 amino acid sequence. The analog carries a substitution and a thirteen amino acid extension so that it evades the binding proteins, which is the reason it exists and the reason evidence does not transfer between them.
Does this approval support using IGF-1 LR3?
No. It covers a different molecule, in children, for a rare deficiency. The analog has no registered trial of any kind.
Why does this page not give dosing or warnings?
Both are prescribing information used alongside monitoring. Lifting them onto a reference page removes what made them usable, and this site's editorial standards do not permit it.
Is it banned in sport?
Yes, by name. The WADA 2026 Prohibited List at S2.3 names insulin-like growth factor 1 and mecasermin and extends to their analogues. It is prohibited at all times and is a non-Specified Substance.
What is still unknown from this page?
Whether any of the 29 records has posted results, what the investigator-led trials outside the licence found, and the approval date and regulatory history behind BLA021839. The label was also read through an API rather than from the label document.
References
- US Food and Drug Administration. INCRELEX (mecasermin) injection prescribing information. Biologics licence application BLA021839, Ipsen Biopharmaceuticals, Inc., subcutaneous route. Read through the openFDA drug label API on 23 August 2026. Carries the approved indication and the limitation of use quoted on this page. The label document itself was not read, which is recorded as an open item. openFDA drug label. 2026. Increlex label
- Ipsen. Prepubertal Children With Growth Failure Associated With IGF-1 Deficiency. Phase 3, 137 participants, completed. Read through the ClinicalTrials.gov v2 API on 23 August 2026. ClinicalTrials.gov. 2005. NCT00125164
- Ipsen. Long-Term Treatment With rhIGF-1 in Growth Hormone Insensitivity Syndrome. Phase 2/3, 92 participants, completed. ClinicalTrials.gov. 2007. NCT00571727
- Massachusetts General Hospital. IGF-1 and Bone Loss in Women With Anorexia Nervosa, 148 participants, completed; and Effects of Anorexia Nervosa on Peak Bone Mass, Phase 3, 75 participants, completed. Investigator-led work outside the licensed indication. Registry records read; no publication was read. ClinicalTrials.gov. 2011. NCT01406444
- Ipsen. IGFD Registry: A Patient Registry for Monitoring the approved population after licensing. 1,378 participants, terminated. ClinicalTrials.gov. 2008. NCT00747604
- Esteve Pharmaceuticals. Global Patient Registry to Monitor Long-term Safety. 500 participants, recruiting as of 23 August 2026. ClinicalTrials.gov. 2009. NCT00903110
- ClinicalTrials.gov. Registry sweep for mecasermin, Increlex, mecasermin rinfabate, iPlex, rhIGF-1, IGF-1 LR3 and Long R3 IGF-1, run through the v2 API on 23 August 2026 and filtered to records whose interventions name one of those drugs. Twenty-nine records survive the filter. An unfiltered query returns 135, because IGF-1 is a widely measured biomarker. ClinicalTrials.gov. 2026. ClinicalTrials.gov
- World Anti-Doping Agency. The 2026 Prohibited List. Section S2.3, Growth Factors and Growth Factor Modulators, carries the entry: Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues. The S2 class heading states that the class is prohibited at all times, in and out of competition, and that all substances in it are non-Specified. Read in full on 23 August 2026. World Anti-Doping Agency. 2026. WADA 2026 Prohibited List
- White A, Stremming J, Wesolowski SR, Al-Juboori SI, Dobrinskikh E, Limesand SW, Brown LD, Rozance PJ. IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep. Am J Physiol Endocrinol Metab. 2025. PMID 39679943 DOI 10.1152/ajpendo.00259.2024 Cited here for its description of the analog's engineering, which is what separates that molecule from this one.
- Stremming J, White A, Donthi A, Batt DG, Hetrick B, Chang EI, Wesolowski SR, Seefeldt MB, McCurdy CE, Rozance PJ, Brown LD. Sheep recombinant IGF-1 promotes organ-specific growth in fetal sheep. Front Physiol. 2022. PMID 36091374 Cited for what unmodified IGF-1 does in the preparation the analog was also tested in.