Fair enough, i have not used Lr3 so cannot use personal experience as you can with this one. MGF i have used and when used correctly, is amazing.
Below is an abstract from a study using MGF. I cannot find many using LR3 showing this.
The fact that IGF-1 can act either as a hormone or as a local factor has complicated the analysis and interpretation of IGF-1 function, as well as its therapeutic application in different disease models. At the structural level, IGF-1 shares a 50% amino acid similarity with insulin (reviewed in Ref. [1]) but unlike the insulin gene, the IGF-1 gene encodes at least four different IGF-1 isoforms, originating from alternative splicing, alternative promoter usage and post-translational modification [4] and [5]. The different isoforms vary in structure and function and are referred to as circulating (class 2) and local (class 1) IGF-1 [5] and [6]. The variation in IGF-1 isoform expression probably reflects an underlying complexity of IGF-1 actions. Circulating IGF-1 has consistently been associated with cancer [7], and many of the clinical trials using IGF-1 have been interrupted as a result of the potential tumorigenic effects. An autocrine form of IGF-1, called mechano growth factor (MGF), is rapidly activated and subsequently repressed in damaged and in exercised muscles, suggesting that MGF acts as a separate growth factor, having an important role in the regenerative capacity of senescent skeletal muscle [8]." -IGF-1, inflammation and stem cells: interactions during muscle regeneration, Foteini Mourkioti, Trends in Immunology Volume 26, Issue 10, October 2005, Pages 535–542