IGF-1

What it measures 

Measures the primary mediator of growth hormone activity. Sits at the intersection of muscle health, recovery capacity, and biological aging, with a narrow optimal range that shifts as you get older. 

Best for 

Anyone experiencing poor exercise recovery, muscle loss, persistent low energy, or those actively tracking their biological age. Relevant for both under and overtraining. 

If results need attention 

Your Protocol doctor will review your IGF-1 in the context of your full hormone picture and guide you on training, nutrition, sleep, or specialist investigation where appropriate.