IGF-1 does help build muscle tissue...the hypothesis is that the gains you see from GH are actually due to IGF-1 stimulation/release.
As far as colostrum, while it probably does contain IGF-1 AT THE SOURCE when consumed from a breast, all colostrum supps are BOVINE colostrum, and usually are heat pressed into tablets.
Now, the problem is two-fold:
1. IGF-1 needs to be refrigerated to remain active.
2. All studies done on IGF-1 used injectables...IGF-1 is extremely expensive, and you could buy a new house for the cost of the gallon or so you would need to drink to achieve oral bio-efficacy.
The bottom line is that any claims of increasing IGF-1 levels in the body by taking bovine colostrum pills are false.
As Prince said, colostrum has been on the market for over a decade, and it's never lived up to any claims.
(Logically, if colostrum, a SUPER CHEAP substance, was able to boost IGF-1 levels, why would Professional BBrs and Researchers pay hundreds of dollars a MILLIGRAM for the IGF-1 injectable?)