Head-to-head comparison
| Property | IGF-1 DES | IGF-1 LR3 |
|---|---|---|
| Category | Muscle & Growth | Muscle & Growth |
| Legal Status | Research Only | Research Only |
| Primary Route | subcutaneous | subcutaneous |
| Half-life | ~20–30 minutes | ~20–30 hours |
| Mol. Weight | 7,371.4 Da | 9,117 Da |
| Side Effects | Hypoglycemia (dose-dependent), Injection site pain or swelling, Jaw pain or facial growth with chronic high-dose use | Hypoglycemia (dose-dependent, serious), Fatigue, Jaw pain |
Key differences
- Mechanism: Both activate the IGF-1 receptor (IGF-1R) via PI3K/Akt/mTOR and MAPK/ERK pathways; IGF-1 DES uniquely drives localized satellite cell activation and muscle hyperplasia at injection sites.
- Half-life: IGF-1 DES has a very short half-life of 20-30 minutes; IGF-1 LR3 has a dramatically longer half-life of 20-30 hours, approximately 60x longer.
- Potency: IGF-1 DES is approximately 10-fold more potent than native IGF-1 in vitro; IGF-1 LR3 is approximately 3-fold more potent than native IGF-1.
- IGFBP binding: IGF-1 DES has dramatically reduced binding to IGF-binding proteins due to N-terminal truncation; IGF-1 LR3 reduces IGFBP binding by approximately 1000-fold through its structural modifications.
- Effect scope: IGF-1 DES produces highly localized effects confined to tissue near the injection site; IGF-1 LR3 produces systemic anabolic effects throughout the body.
- Dosing: IGF-1 DES is typically dosed at 20-100 mcg once daily post-workout into target muscles; IGF-1 LR3 is dosed at 20-50 mcg once daily post-workout with systemic distribution.
- Side effects: Both carry hypoglycemia risk; IGF-1 LR3 has documented acromegaly-like symptoms with long-term use due to systemic exposure, while IGF-1 DES risks are more localized.
The verdict
IGF-1 DES and IGF-1 LR3 serve different research purposes despite sharing the IGF-1 receptor as their primary target. IGF-1 DES offers greater potency and site-specific muscle remodeling through its short half-life, making it suited for localized applications. IGF-1 LR3 provides broader systemic anabolic support with its extended half-life. Neither has completed controlled human clinical trials, and both are banned by WADA and classified as research-only compounds.
Frequently asked questions
Some research protocols combine them for localized plus systemic IGF-1R activation, though no controlled studies validate this combination. The rationale is that IGF-1 DES provides intense site-specific effects while IGF-1 LR3 provides background systemic anabolism.
IGF-1 DES is approximately 10-fold more potent than native IGF-1, compared to IGF-1 LR3 at approximately 3-fold. However, IGF-1 DES's very short half-life (20-30 minutes) limits its effects to the injection site, while IGF-1 LR3's effects are distributed systemically over 20-30 hours.
IGF-1 DES has a half-life of only 20-30 minutes, meaning it is cleared from circulation before it can distribute widely. This confines its receptor activation to tissue near the injection site. IGF-1 LR3's 20-30 hour half-life allows it to circulate and reach tissues throughout the body.
Both are classified as research-only compounds with no FDA approval. Both are prohibited by WADA in competitive sport. Neither is a scheduled controlled substance in the US, but they are considered prescription drug analogues in some countries.
Both IGF-1 DES and IGF-1 LR3 can cause dose-dependent hypoglycemia because IGF-1R activation drives glucose uptake. The risk is greater with IGF-1 LR3 due to its systemic distribution and long half-life. Research protocols recommend having fast-acting carbohydrates available during use.