One cup of milk has 25 times more IGF-1 than deer antler spray supplements.
The supplement label claims that each 'serving' of the spray contains 27.5 ng of IGF-1. See the 'Indgredients' tab at the link.
A recent PSU study reports the concentration of IFG-1 in dairy milk: "Concentrations of IGF-1 in milk were similar between conventional milk and milk labeled rbST-free. Organic milk had less (P<0.05) IGF-1 than either conventional or rbST-free milk (2.73 ng/mL vs 3.12 and 3.04 ng/mL, respectively)."
Thus, one cup (or 236.588 mL) of conventional milk contains 738 ng of IGF-1. That's more than 25 times the amount claimed to be in the supplement.