Where the claims come from
The interest is extrapolated from IGF-1’s genuine role in muscle growth, combined with the analogue’s longer half-life. Three different things are routinely called "IGF-1" in marketing: the natural hormone, the FDA-approved drug mecasermin (Increlex), and this research analogue. Evidence or approval for one does not transfer to the others, and only mecasermin has registered trials — fourteen of them.
What evidence exists outside the registry
Published work on the LR3 analogue is animal and laboratory only: fetal sheep infusion studies, mouse work, and recombinant-expression papers. One mouse study of intranasal LongR3 failed to preserve cognition. The analogue does appear in doping-control literature, which is evidence that people use it, not evidence that it works.
- Increlex (mecasermin) FDA label — The approved IGF-1 product — a different molecule from the LR3 analogue, approved for severe primary IGF-1 deficiency in children.
- LongR3 IGF-1 in fetal sheep — Representative of the animal literature that exists for the analogue.
- Detection of LongR3 IGF-1 in doping control — Evidence of human use; not evidence of effect.
Approved for, studied for, sold for
Three separate lists, kept by three separate processes: a regulator decides the first, researchers the second, and whoever is selling it the third. They are often not the same list, and the differences are the most useful thing on this page.
Not approved by the FDA for any use. Nothing has been reviewed for safety, effectiveness or manufacturing quality.
No registered trial in ClinicalTrials.gov lists a studied condition for this compound. That is a gap in the registry, not a finding that it was tested and failed. See what evidence exists outside the registry below.
- Muscle growth
- Recovery
- Nutrient partitioning
Every trial on record
Every registered human study we can find for IGF-1 LR3. Click any ID to read the original record — we would rather you checked us than trusted us.
What regulators have said
We searched FDA's list of bulk drug substances nominated for use in pharmacy compounding and did not find IGF-1 LR3 on it, in any category. That means there is no published FDA safety assessment to report — not that the compound has been reviewed and cleared.
FDA — bulk drug substances that may present significant safety risks
Why you may see a different number
Published papers and registered trials are different things. A study can be written up without ever appearing on a trial registry — particularly older work, work done outside the US and EU, and animal research. We count registered human trials because they can be independently verified. A count of zero here means nobody has registered a human trial, not that no paper exists.
Common questions about IGF-1 LR3
How many human trials does IGF-1 LR3 have?
None on ClinicalTrials.gov. We found no registered interventional study of IGF-1 LR3 in humans. Published human research may still exist — registration only became standard in the mid-2000s — but it is not in the registry this count comes from.
Is IGF-1 LR3 FDA approved?
No. IGF-1 LR3 is not approved by the FDA for any indication. Compounded or "research use only" preparations are not FDA-approved and receive no premarket review for safety, effectiveness, or manufacturing quality.
Where does this data come from?
ClinicalTrials.gov, the US public registry of clinical studies. We count interventional human studies only — observational studies are not evidence of effect. Every trial on this page links to its original record so you can check us rather than trust us.
More on IGF-1 LR3: how many human trials it has · is it FDA approved · has it been studied for safety
Get told when this changes
One email a week: what moved in the research, and which claims the record doesn't support. Free, and you can leave in one click.