IGF-1 LR3 vs MK-677: side-by-side comparison
Long R3 IGF-1 · Long-R3-IGF-I · LR3 IGF-1
A synthetic analogue of insulin-like growth factor 1 (IGF-1), the main downstream mediator of growth hormone. LR3 ("Long R3") is engineered to bind the IGF binding proteins (IGFBPs) much less than native IGF-1; because most native IGF-1 is normally bound by IGFBPs, cutting that binding leaves more free peptide in circulation and dramatically lengthens its active half-life. It is used in the bodybuilding community for a longer, systemic version of IGF-1's anabolic signalling. Note: the exact LR3 half-life figure widely quoted (~20-30 h) comes from research-reagent/community sources, not an approved-drug label.
Ibutamoren · MK677 · Nutrobal
An oral ghrelin mimetic that stimulates GH pulses. Technically not a peptide but a non-peptide agonist of the ghrelin receptor that increases growth hormone and IGF-1 levels.
7 / 10 natty scale / 4
Same lane
Both sit in the same class and are run for bulking, recovery. This is a like-for-like comparison: read the gaps as real trade-offs.
The tape
Core ratings
The same three rulers every entry on the site is scored with, read head to head.
Natty scale
1 natural · 10 heavyΔ3
Effectiveness
Documented effect · of 5Δ1
Side-effect severity
Documented burden · of 5Δ0.5
Cost side
Body-load fingerprint
Where each one actually lands its strain, on the calculator's thirteen channels. Tap a row for what it means and which labs track it.
Cardiometabolic
Organ strain
Hormonal
Systemic
Injection & site care
Bars show strain at each one's typical protocol, not your dose. ≈ marks values inferred from side-effect data or category rather than hand-graded. For your numbers, run the calculator.
Logistics
The vitals
Benefit side
What each is for
Shared goals carry both dots; a goal with one dot belongs to that side alone.
Run for
Documented upside
- Much longer active half-life than native IGF-1 (reduced IGFBP binding)
- Potent activation of the PI3K/Akt/mTOR protein-synthesis pathway
- Systemic (whole-body) rather than fleeting local action
- Does not suppress natural testosterone - no PCT required
- Complements GH and anabolic steroid protocols
Run for
Documented upside
- Oral administration (no injections)
- Improved sleep quality
- Increased appetite
- Elevated IGF-1 levels
- Enhanced recovery
The downsides
Side effects, aligned
Each entry's documented side effects, sorted onto the same body systems so the gaps and the overlaps are visible. Tap any effect for the detail.
None documented
None documented
None documented
The exit
Hormonal fallout & recovery
What each does to your own hormone axis while on, and what leaving it costs.
IGF-1 LR3
IGF-1 does not suppress natural testosterone production - no PCT required for IGF-1 LR3 alone. If stacked with suppressive compounds (e.g. steroids), PCT is needed for those compounds.
MK-677
Does not suppress testosterone. No PCT required.
Read-out
How they separate
- 01
Enhancement
IGF-1 LR3 sits 3 points higher on the natty scale (7/10 vs 4/10): a bigger step beyond natural at its typical protocol.
- 02
Side-effect bill
IGF-1 LR3's documented side-effect severity is heavier (3.5/5 vs 3/5). The body-load fingerprint above shows where that weight actually lands.
- 03
Body load
The widest gap at typical protocols is liver strain (IGF-1 LR3 4.4/10 vs 0/10), then estrogen load (MK-677 4/10 vs 0/10).
- 04
Coming off
Neither requires PCT: both leave the natural testosterone axis running.
- 05
Logistics
IGF-1 LR3 runs as subcutaneous, MK-677 as oral; typical runs are 4-6 weeks vs 8-12 weeks.
- 06
Tested athletes
Both are WADA-prohibited: neither belongs anywhere near tested competition.
Generated from each entry's data file. Descriptive, not a recommendation; nothing here is medical advice.