Are Serum IGF1 Tests Pointless for Bodybuilding?

Muscle growth is primarily influenced by IGF-1 produced locally within the muscle tissue (autocrine/paracrine effects) rather than systemic (endocrine) IGF-1 levels found in the blood. Local IGF-1 is more directly involved in muscle repair and hypertrophy following resistance training and things like using insulin and HGH.

The elevation of serum IGF1 from driving your estrogen through the roof doesn't mean much when it comes to actual muscle growth.

There's no well-established correlation between Serum IGF-1 and muscle growth. Systemic IGF-1 measured in the serum reflects overall body levels but does not necessarily correlate with the IGF-1 activity within the muscle tissue where growth occurs.

Protein, glucose, and insulin stimulate IGF production. Estrogen affects IGF by increasing liver production of binding proteins, which can make IGF ineffective. High estrogen levels lead to more binding protein 1, causing IGF to be bound and unable to enter cells. This results in higher serum IGF levels that don't contribute to muscle growth. This is why women, especially during ovulation and pregnancy, have more bound IGF and less muscle growth, as energy is directed towards the embryo/fetus rather than muscles.

This test is misused by bodybuilders and is meant to be used to diagnose disease, not potential muscle growth. 

Serum IGF tests are mostly meaningless tests for bodybuilding purposes. #bodybuilding #igf1 #hypertrophy