IGF-1
Insulin-like Growth Factor-1 · IGF-I · Somatomedin-C · rhIGF-1 · Mecasermin (recombinant human IGF-1)
Last updated
At a glance
- Muscle Growth
- 6/10
- Recovery
- 6/10
- Strength
- 4/10
- Fat Loss
- 2/10
- Endurance
- 2/10
- Cognition
- 1/10
Overview
IGF-1 is a growth factor involved in growth and muscle adaptation. Mecasermin is its recombinant human form, used medically for specific childhood growth disorders. Fitness communities discuss IGF-1 for muscle growth and recovery, often alongside the distinct LR3 and DES analogues. This guide explains the differences, the research behind that interest and why dosage or cycle information must identify the exact compound.
Which IGF-1 are you researching?#
| Name | What it describes | Continue reading |
|---|---|---|
| Native IGF-1 / mecasermin | The 70-amino-acid human growth factor and its recombinant form | This page |
| IGF-1 LR3 | An extended analogue with a changed amino-acid sequence | LR3 profile and research supplier listings |
| IGF-1 DES | An analogue missing the first three amino acids | DES profile |
The mecasermin label, LR3 structural study and DES laboratory study establish these distinctions. A vial labelled LR3 is not interchangeable with mecasermin.
Compare native IGF-1 with LR3 before comparing protocols or products.
How IGF-1 works
Growth-factor signaling#
IGF-1 participates in signaling that regulates muscle protein balance. Clemmons' review discusses findings from animal models of muscle loss and the pathways investigated as possible therapeutic targets. Those mechanisms explain research interest; they do not quantify a person's expected gym results.
Local production and circulating IGF-1#
Muscle can produce IGF-1 locally. Adams' review examines its relationship with loading and adaptation. Local production within tissue is a different experimental question from injecting a peptide near a muscle, so the review should not be read as a site-injection protocol.
Binding proteins matter#
IGF-binding proteins regulate IGF availability. In human pharmacokinetic research, rhIGF-1 clearance differed between healthy volunteers and people with growth hormone receptor deficiency. This is why a single half-life number can obscure the population and formulation being studied.
Protocol
IGF-1 dosage: identify the preparation first#
| Reference | Compound and setting | What it can tell you |
|---|---|---|
| INCRELEX prescribing information | Mecasermin for its specified pediatric indication | Product-specific, clinician-directed dosing |
| Guler 1987 | Recombinant human IGF-1 in eight healthy adults | Short-term metabolic effects in an experimental setting |
| Grahnén 1993 | Subcutaneous rhIGF-1 in healthy volunteers and patients with receptor deficiency | Pharmacokinetics differed between populations |
| LR3 guide | A different IGF-1 analogue | Keep its reported protocols separate from native IGF-1 |
The studies above do not establish a beginner-to-advanced bodybuilding dose ladder for native IGF-1. A research-vial strength is also not a prescribed administration amount.
The peptide calculator can perform concentration arithmetic from supplied inputs. It cannot select the appropriate compound, formulation or dose.
Cycle length & outcomes
IGF-1 cycle length and community discussions#
Community posts sometimes use “IGF-1” loosely. In this muscle-growth discussion, participants mention LR3, DES and mecasermin separately and describe other compounds alongside them. That illustrates the interest and naming problem; it does not establish a native-IGF cycle or isolate an effect.
Keep three questions separate when reading a report: which molecule was used, what else was used, and what was actually measured. LR3 or DES schedules should stay with their own profiles.
The human metabolic study and muscle-biology review answer different questions from an optimal bodybuilding cycle. Neither establishes a universal cycle length, break interval or predictable weekly gain for native IGF-1.
Risks & mistakes
Glucose effects#
In Guler's small human experiment, recombinant IGF-1 lowered blood glucose. This supports taking hypoglycemia seriously; it does not establish a safe self-directed combination with insulin.
Product-specific clinical precautions#
The mecasermin label describes hypoglycemia, allergic reactions, intracranial hypertension and other precautions for its treated population. Those rates and instructions cannot be transferred directly to LR3 or DES. Medical use requires individualized supervision.
Severe symptoms such as a seizure, loss of consciousness or difficulty breathing require urgent medical help.
Stack & combine
Multipliers applied when these compounds run together. Values > 1 indicate a bonus on that axis. Tap a partner to expand the mechanism.
| Partner | Type | Lean | Fat loss | Recovery |
|---|---|---|---|---|
| synergistic | ×1.00 | ×1.00 | ×1.00 |
Pharmacokinetic conflicts, competing pathways, or compounded toxicity. Multipliers below 1 indicate the affected axis.
| Partner | Type | Lean | Fat loss | Recovery |
|---|---|---|---|---|
| antagonistic | ×1.00 | ×1.00 | ×1.00 |
FAQ — IGF-1
Research & citations
6 studies cited on this page.
Conclusion
Start with the molecule: native IGF-1, LR3 and DES have different identities and evidence. This page covers native IGF-1 and mecasermin; the analogue profiles cover their respective research and product listings.
Compare native IGF-1 and LR3, review dosage contexts, or view LR3 research suppliers.