IGF-1 LR3 (Long R3 IGF-1) vs Sermorelin
Updated September 21, 2026 · Reviewed by the PeptidesDB Editorial team
A data-driven comparison of IGF-1 LR3 (Long R3 IGF-1) and Sermorelin (also searched as Sermorelin vs IGF-1 LR3 (Long R3 IGF-1)) — effect profiles, evidence, side effects, and which suits weight loss, muscle, or healing goals.
Verdict
IGF-1 LR3 (Long R3 IGF-1) centers on muscle, while Sermorelin leans toward muscle. On indexed research, Sermorelin is ahead (IGF-1 LR3 (Long R3 IGF-1): 14 studies, Human evidence; Sermorelin: 19, Human evidence). Choose by goal — and read the primary studies. This is research information, not medical advice.
Key takeaways
- •IGF-1 LR3 (Long R3 IGF-1) is strongest for muscle; Sermorelin for muscle.
- •Evidence: IGF-1 LR3 (Long R3 IGF-1) Human evidence (14 studies) vs Sermorelin Human evidence (19).
- •Both are research-use compounds — not FDA-approved.
Effect profiles, overlaid
At a glance
IGF-1 receptor agonist | Muscle growth
GHRH Mimetic | Growth Hormone Deficiency
IGF-1 LR3 (Long R3 IGF-1) vs Sermorelin: side-by-side
| Metric | IGF-1 LR3 (Long R3 IGF-1) | Sermorelin |
|---|---|---|
| Class | Muscle | Muscle |
| Regulatory status | Research use only | Research use only |
| Evidence grade | Human evidence | Human evidence |
| Studies indexed | 14 | 19 |
| Research level | Preclinical | Moderate Research |
| Strongest effect | Muscle & body comp | Muscle & body comp |
| Healing & recovery | 1.0 | 3.0▲ |
| Muscle & body comp | 5.0▲ | 4.0 |
| Metabolic & appetite | 3.0▲ | 3.0▲ |
| Neuro & mood | 2.0▲ | 2.0▲ |
| Sleep & circadian | 0.0 | 1.0▲ |
| Inflammation & immune | 1.0 | 2.0▲ |
| Skin & aesthetics | 2.0 | 3.0▲ |
▲ marks the higher AI-assigned effect score (0–5, describing where the literature concentrates — not clinical efficacy).
Mechanism & pharmacokinetics
| Property | IGF-1 LR3 (Long R3 IGF-1) | Sermorelin |
|---|---|---|
| Mechanism | IGF-1 receptor agonist | GHRH (1–29) analog |
| Route | Subcutaneous injection | Subcutaneous injection |
| Half-life | ~20-30 hours | — |
Established pharmacology — curated for well-characterized compounds and AI-summarized otherwise. A blank (—) means no reliable single value is published (half-life figures for some peptides genuinely disagree across sources). Verify against primary sources such as FDA labels and ClinicalTrials.gov.
What is IGF-1 LR3 (Long R3 IGF-1)?
IGF-1 LR3 is a long-acting synthetic IGF-1 analog with reduced binding-protein affinity, used as a research-grade IGF-1 receptor agonist studied for muscle and tissue growth.
Full IGF-1 LR3 (Long R3 IGF-1) profile, mechanism & studies →What is Sermorelin?
Sermorelin is a synthetic peptide that mimics growth hormone-releasing hormone (GHRH), stimulating the pituitary gland to produce and release endogenous growth hormone. It has been investigated for its potential therapeutic applications, particularly in the context of growth hormone deficiencies and other related conditions.
Full Sermorelin profile, mechanism & studies →Which is better for your goal?
| Goal | Better fit | Why |
|---|---|---|
| Healing | Sermorelin | 3.0/5 effect signal |
| Muscle | IGF-1 LR3 (Long R3 IGF-1) | 5.0/5 effect signal |
| Metabolic | Even | Both ~3.0/5 |
| Neuro | Even | Both ~2.0/5 |
| Sleep | Sermorelin | 1.0/5 effect signal |
| Inflammation | Sermorelin | 2.0/5 effect signal |
| Skin | Sermorelin | 3.0/5 effect signal |
Fit reflects community-perceived effect profiles — not head-to-head trials. Read each peptide's studies before deciding.
Can you stack IGF-1 LR3 (Long R3 IGF-1) and Sermorelin?
People sometimes combine peptides that target different pathways, but there is little controlled research on this specific pairing and the interactions aren't well characterized. Because neither compound is FDA-approved, we don't publish stacking or dosing protocols here. Any combination should be discussed with a qualified clinician.
IGF-1 LR3 (Long R3 IGF-1) vs Sermorelin: side effects
No community-reported effects logged yet.
No community-reported effects logged yet.
Anonymous community reports (count = number of reports), not clinical incidence rates.
What the research says
IGF-1 LR3 (Long R3 IGF-1) has 14 approved studies indexed (Human evidence), and Sermorelin has 19 (Human evidence). The Librarian re-checks PubMed, Europe PMC and ClinicalTrials daily, so these counts move. Open each profile to read the summaries and sources.
Frequently asked questions
Is IGF-1 LR3 (Long R3 IGF-1) or Sermorelin better?
It depends on your goal. IGF-1 LR3 (Long R3 IGF-1) is strongest for muscle; Sermorelin for muscle. Sermorelin has more indexed studies (19). See the goal-by-goal breakdown above.
Is IGF-1 LR3 (Long R3 IGF-1) or Sermorelin better for weight loss?
They score similarly on the metabolic/appetite axis in the community data.
Is IGF-1 LR3 (Long R3 IGF-1) or Sermorelin better for muscle?
IGF-1 LR3 (Long R3 IGF-1) leads on the muscle & body-composition axis (5.0/5).
Which has more research, IGF-1 LR3 (Long R3 IGF-1) or Sermorelin?
IGF-1 LR3 (Long R3 IGF-1) has 14 approved studies indexed (Human evidence); Sermorelin has 19 (Human evidence). Higher counts mean more to read, not proven superiority.
Can you stack IGF-1 LR3 (Long R3 IGF-1) and Sermorelin?
Some users combine peptides, but there's little controlled data on this specific pairing, and interactions aren't well characterized. We don't publish stacking protocols for compounds that aren't FDA-approved. Discuss any combination with a qualified clinician.
What are the side effects of IGF-1 LR3 (Long R3 IGF-1) vs Sermorelin?
IGF-1 LR3 (Long R3 IGF-1): no community-reported effects logged yet. Sermorelin: none logged yet. These are anonymous reports, not incidence rates — see each profile.
Is IGF-1 LR3 (Long R3 IGF-1) or Sermorelin FDA-approved?
IGF-1 LR3 (Long R3 IGF-1) is a research-use compound and is not FDA-approved. Sermorelin is not FDA-approved. Research-use status is not a legal clearance to compound or use in humans.
Is Sermorelin better than IGF-1 LR3 (Long R3 IGF-1)?
For muscle, Sermorelin has the edge; for muscle, IGF-1 LR3 (Long R3 IGF-1) does. Neither is universally "better" — it's goal-dependent, and both should be weighed against their evidence base above.
Comparing related peptides
Regulatory & legal status
IGF-1 LR3 (Long R3 IGF-1) and Sermorelin are research-use compounds and are not FDA-approved for human use. FDA approval and compounding rules for peptides change frequently, and research-use status is not a legal clearance for human use. The FDA does not review compounded drugs for safety, effectiveness, or quality. Verify current status with primary sources before acting. Last reviewed September 21, 2026.