IGF-1 DES vs Mecasermin
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: des(1-3)IGF-1, Des(1-3) IGF-I
IGF-1 DES is insulin-like growth factor 1 with its first three amino acids chopped off, leaving a 67-residue peptide. That small cut makes it bind poorly to the IGF binding proteins that normally keep IGF-1 in check, so more of it reaches the receptor and it acts stronger, but shorter. It occurs naturally in small amounts (it was first isolated from human fetal brain tissue) and is sold online as a muscle-building research peptide. There are no human trials of it at all, so everything said about it in people is extrapolation.
Also: Increlex, rhIGF-1
Mecasermin is recombinant human IGF-1, identical to the 70-amino-acid hormone your liver makes in response to growth hormone. Sold as Increlex, it was FDA approved in 2005 for a narrow group: children with severe primary IGF-1 deficiency (mostly Laron syndrome) or a growth hormone gene deletion with antibodies against GH. In those kids it is the only thing that works, because GH cannot do its job. It is not a GH substitute, and its real risks (low blood sugar, tonsil overgrowth, cancer warnings) are why it stays a specialist drug.
Key Comparison Insights
- Mecasermin is FDA approved, while IGF-1 DES remains in research stages.
- Both peptides belong to the Growth Hormone category, suggesting similar primary applications.
- Mecasermin has stronger research evidence (FDA Approved) compared to IGF-1 DES (Preclinical).
Detailed Comparison
| Attribute | IGF-1 DES | Mecasermin |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| FDA Status | Not FDA Approved | FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Like regular IGF-1, des(1-3)IGF-1 activates the type 1 IGF receptor, a tyrosine kinase receptor closely related to the insulin receptor. That switches on PI3K/Akt and MAPK signalling, which drives cell growth, protein synthesis and glucose uptake. The difference is the binding proteins. In the body almost all IGF-1 rides around bound to IGFBPs, which limit how much can hit the receptor. Removing the N-terminal tripeptide (Gly-Pro-Glu) sharply weakens IGFBP binding while leaving receptor binding intact. In a 1992 JCI study on rat granulosa cells, des(1-3)IGF-1 was about 10 times more potent than intact IGF-1 when binding proteins were present, and roughly equal once they were removed, which shows the extra potency comes from dodging the binding proteins rather than a stronger receptor hit. The trade-off: unbound IGF-1 is cleared fast, so its action is short and local, which is why people inject it into a specific muscle. It also carries IGF-1's insulin-like effect on blood sugar. | Normally, growth hormone binds receptors in the liver and other tissues and triggers IGF-1 production. IGF-1 then activates the type 1 IGF receptor on bone, cartilage and other cells, driving growth. In Laron syndrome the GH receptor is broken, so GH levels are high but IGF-1 stays low. Mecasermin skips the broken step and supplies IGF-1 directly. Because the IGF-1 receptor is a close relative of the insulin receptor, and because IGF-1 can also bind the insulin receptor at higher levels, it lowers blood sugar. That is why the label says to give it within about 20 minutes of a meal or snack. It is mostly carried by IGF binding protein 3 in blood, and its clearance depends on IGFBP-3 levels; the label reports a mean terminal half-life of about 5.8 hours in children with severe primary IGF-1 deficiency. |
| Common Dosing | Community-reported 20-100 mcg per day Usually once daily on training days | 0.04-0.08 mg/kg twice daily to start Twice daily |
| Administration | Intramuscular or subcutaneous injection (community practice); studied by injection in animals only | Subcutaneous injection, rotating sites, within about 20 minutes before or after a meal or snack |
| Typical Duration | Community reports describe short cycles of about 4-6 weeks; there is no human data on safe duration | Long-term, until growth plates close (closed epiphyses are a contraindication) |
| Best Time to Take | Around training, per community practice | Shortly before or after a meal or snack, twice daily |
Possible Side Effects May vary by individual |
|
|
| Research Summary | The research is old, small, and entirely in cells and animals. Sara, Carlsson-Skwirut and colleagues isolated a truncated variant of IGF-1 from human fetal brain in 1986 (PNAS). In GH-deficient lit/lit mice, Gillespie and colleagues (J Endocrinol, 1990) found that 3 microgram daily injections of des(1-3)IGF-1 increased body length about as much as 30 micrograms of regular IGF-1, confirming its higher potency in a living animal; organ weights (kidney, heart) also rose. Adashi and colleagues (JCI, 1992) showed the roughly 10-fold potency gain disappears when IGF binding proteins are removed. Beyond that, it is mostly a lab tool for studying the IGF system. There are no human trials, no pharmacokinetic data in people, and no safety data. Claims about local muscle hyperplasia, fat loss, or recovery are bodybuilding lore built on IGF-1 biology, not on studies of this peptide. Theoretical risks are the same as for IGF-1 and other analogues: low blood sugar, and long-term concerns about feeding the growth of existing tumours, since IGF-1 signalling is a known growth pathway in several cancers. Quality is another unknown: the material sold online has no pharmaceutical oversight. | The approval rests on five pooled studies (four open-label, one placebo-controlled) in 71 children with severe primary IGF-1 deficiency, 87% of whom had Laron syndrome. Height velocity rose from 2.8 cm per year before treatment to 8.0 cm per year in year 1, then settled around 4.5 to 5.8 cm per year in later years, still above baseline. Height scores improved but these children stayed very short (mean height SDS went from -6.7 to about -5.2 after 8 years), so it helps rather than normalizes. Hypoglycemia was reported in 42% of children at least once, and tonsillar hypertrophy in 15%. The label carries warnings for hypoglycemic seizures, anaphylaxis, intracranial hypertension, slipped capital femoral epiphysis (added July 2025), scoliosis progression, and postmarketing reports of malignant neoplasms; malignancy is a contraindication. Ownership changed recently: Eton Pharmaceuticals bought Increlex from Ipsen in December 2024 and in 2025 licensed rights outside the US to Esteve. Adult use, anti-aging use, and bodybuilding use are off-label and unsupported by trials. |
Frequently Asked Questions: IGF-1 DES vs Mecasermin
What is the difference between IGF-1 DES and Mecasermin?
IGF-1 DES is a growth hormone peptide that igf-1 des is insulin-like growth factor 1 with its first three amino acids chopped off, leaving a 67-residue peptide. that small cut makes it bind poorly to the igf binding proteins that normally keep igf-1 in check, so more of it reaches the receptor and it acts stronger, but shorter. it occurs naturally in small amounts (it was first isolated from human fetal brain tissue) and is sold online as a muscle-building research peptide. there are no human trials of it at all, so everything said about it in people is extrapolation. Mecasermin is a growth hormone peptide that mecasermin is recombinant human igf-1, identical to the 70-amino-acid hormone your liver makes in response to growth hormone. sold as increlex, it was fda approved in 2005 for a narrow group: children with severe primary igf-1 deficiency (mostly laron syndrome) or a growth hormone gene deletion with antibodies against gh. in those kids it is the only thing that works, because gh cannot do its job. it is not a gh substitute, and its real risks (low blood sugar, tonsil overgrowth, cancer warnings) are why it stays a specialist drug. The main differences lie in their mechanisms of action and clinical applications.
Which is better, IGF-1 DES or Mecasermin?
Neither is universally "better" - the choice depends on your specific goals. IGF-1 DES is typically used for growth hormone purposes, while Mecasermin is used for growth hormone. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can IGF-1 DES and Mecasermin be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using IGF-1 DES and Mecasermin together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.