Eggs and myostatin

As you will have read previously one very interesting substrate of egg protein contained with in the egg yolk is element known as follistatin. Follistatin is highly effective as Myostatin antagonist inhibitor or blocker. Myostatin is a muscle growth inhibitor so the potential ingestion of follistatin is a very positive factor for anyone looking to gain lean muscle mass naturally.

Below are extracts from a couple of studies looking at the application of follistatin ingested from fertile egg yolk extract.

Follistatin is known to antagonise the function of several members of the TGF-beta family of secreted signalling factors, including Myostatin, the most powerful inhibitor of muscle growth characterised to date. In this study, we compare the expression of Myostatin and Follistatin during chick development and show that they are expressed in the vicinity or in overlapping domains to suggest possible interaction during muscle development. We performed yeast and mammalian two-hybrid studies and show that Myostatin and Follistatin interact directly. We further show that single modules of the Follistatin protein cannot associate with Myostatin suggesting that the entire protein is required for the interaction. We analysed the interaction kinetics of the two proteins and found that Follistatin binds Myostatin with a high affinity of 5.84 x 10(-10) M. We next tested whether Follistatin suppresses Myostatin activity during muscle development. We confirmed our previous observation that treatment of chick limb buds with Myostatin results in a severe decrease in the expression of two key myogenic regulatory genes Pax-3 and MyoD. However, in the presence of Follistatin, the Myostatin-mediated inhibition of Pax-3 and MyoD expression is blocked. We additionally show that Myostatin inhibits terminal differentiation of muscle cells in high-density cell cultures of limb mesenchyme (micromass) and that Follistatin rescues muscle differentiation in a concentration-dependent manner. In summary, our data suggest that Follistatin antagonises Myostatin by direct protein interaction, which prevents Myostatin from executing its inhibitory effect on muscle development.

Another study:

Absorption Profile and Hormonal Influence of Fertilized Egg Yolk Ingestion in the Human.

Fertile egg yolks contain significant concentrations of follistatin. In an effort to identify whether this orally ingested source of naturally occurring follistatin is actually absorbed and pharmacokinetically active in the human model, this study was undertaken. A male subject was chosen because the normal baseline male physiology does not regularly contain any measurable concentration of follistatin. Follistatin rich fertile egg yolk powder properly processed to preserve active follistatin was used.
After initial blood draw and subsequential oral follistatin dosing, serum follistatin levels were qualitatively and quantitatively measured as an indicator of absorption. In addition, since we know follistatin is a negative modulator of myostatin, serum myostatin levels were qualitatively and quantitatively measured as an indication of hormonal influence and thus true pharmacokinetic activity. Testing utilized follistatin and myostatin standardized for verification. Confirmations were run by ELISA and quantitations by Liquid Chromatography Tandem Mass Spectrometer with third degree fragmentation.
Results showed as predicted, a zero level of follistatin at baseline with a myostatin level of 46 pg/ml, 12 hours after follistatin dosing. Serum follistatin measured 57.1 pg/ml with a decline of myostatin to 34 pg/m1, 24 hours after the initial dosing, follistatin levels began to predictably drop from the time of initial dosing to 11.4 pg/ml. Yet myostatin continued to decline slightly with a 24-hour level of 31 pg/ml. These results clearly indicate that a fertile egg yolk powder properly processed to preserve active follistatin, when orally ingested, results in detectable serum follistatin. Furthermore, this resultant follistatin presence has significant pharmacokinetic activity is shown by the hormonal down regulation of serum follistatin.


Desiccated fertile egg yolk powder processed correctly with maintained levels of follistatin (the myostatin inhibitor) when orally ingested down regulates myostatin.


Department of Veterinary Basic Sciences, Royal Veterinary College, London NW1 OTU, UK

Journal of American College of Nutrition, Vol 25, No5, Abstract 66, October 2006

‘Effect of debulked fertile egg yolk ingestion on Myostatin levels’ Colker C

Follistatin complexes Myostatin and antagonises Myostatin-mediated inhibition of myogenesis.

Amthor H, Nicholas G, McKinnell I, Kemp CF, Sharma M, Kambadur R, Patel K.