Only phosphatic acid from soya speeds up muscle growth

A daily dose of 750 mg phosphatic acid helps strength athletes build up strength and muscle mass faster. Sports scientists at the University of Tampa come to this conclusion in a sponsored study.

Phosphatic Acid

Phosphorus is what helps muscle cells to grow. Anabolic signal molecules generally become active if cells attach a phosphorus group to them at the right spot. That’s textbook stuff. So if you know that, and developed an obsession about your muscularity in adolescence, you’ve probably already wondered whether phosphatic acid supplementation can boost muscle growth.


The researchers published in 2012 a study that did suggest, but didn’t prove that phosphatic acid does indeed possess semi-anabolic properties. The study published a few months ago was larger – and produced strong enough evidence of statistically significant effects.


These effects are shown below. The subjects were young strength athletes, all of whom followed the same training programme for eight weeks. Half of them were given a placebo; the other half took 750 mg phosphatic acid every day.

An asterisk (*) represents a significant effect in terms of the training period (‘before’ versus ‘after’) and a number sign (#) represents a statistically significant effect derived from phosphatic acid versus the placebo treatment. Phosphatic acid led to an extra increase in lean body mass and muscle strength.




The researchers did in-vitro research and discovered that phosphatic acid activates the anabolic key molecule mTOR in muscle cells via the signal molecule p70. Armed with this knowledge they then measured the effect of a number of related molecules on p70.

S-PS = soy-derived phosphatidylserine; S-PI = soy-derived phosphatidylinositol; S-PE = soy-derived phosphatidyl-ethanolamine; S-PC = soy-derived phosphatidylcholine; S-PA = soy-derived phosphatic acid; S-LPA = soy-derived lysophosphatidic acid; DAG = diacylglycerol; G3P = glycerol-3-phosphate; E-PA = egg-derived phosphatic acid.


As you can see, phosphatidylserine, lysophosphatidic acid and phosphatic acid from soya are mTOR boosters, while phosphatic acid derived from eggs has little effect.

“This could be due to the composition of the phosphatic acid molecule”, the researchers suspect. “For instance, Foster et al. have reported differing effects of phosphatic acid based upon the structure of its fatty acid components; wherein, two saturated fatty acids promoted storage, yet one saturated and one unsaturated fatty acid promoted signaling.”

“Thus, the higher unsaturated fat content of soy may explain these observations. This suggests that soy derived phosphatic acid, lysophosphatidic acid, and phosphatidylserine are superior agonists of mTOR signaling, and therefore, they appear to be suitable candidates for augmenting the effects of resistance training on muscle mass.”

Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy.



The lipid messenger phosphatidic acid (PA) plays a critical role in the stimulation of mTOR signaling. However, the mechanism by which PA stimulates mTOR is currently unknown. Therefore, the purpose of this study was to compare the effects of various PA precursors and phospholipids on their ability to stimulate mTOR signaling and its ability to augment resistance training-induced changes in body composition and performance.


In phase one, C2C12 myoblasts cells were stimulated with different phospholipids and phospholipid precursors derived from soy and egg sources. The ratio of phosphorylated p70 (P-p70-389) to total p70 was then used as readout for mTOR signaling. In phase two, resistance trained subjects (n?=?28, 21?±?3 years, 77?±?4 kg, 176?±?9 cm) consumed either 750 mg PA daily or placebo and each took part in an 8 week periodized resistance training program.


In phase one, soy-phosphatidylserine, soy-Lyso-PA, egg-PA, and soy-PA stimulated mTOR signaling, and the effects of soy-PA (+636%) were significantly greater than egg-PA (+221%). In phase two, PA significantly increased lean body mass (+2.4 kg), cross sectional area (+1.0 cm), and leg press strength (+51.9 kg) over placebo.


PA significantly activates mTOR and significantly improved responses in skeletal muscle hypertrophy, lean body mass, and maximal strength to resistance exercise.

PMID: 24959196 [PubMed] PMCID: PMC4066292