What Is Phosphatidic Acid?
In chemical gobbledygook, phosphatidic acid (PA) is a classified as a diacyl-glycerophospholipid, in which two fatty acids and a phosphate group are covalently bonded to a glycerol molecule through ester linkages. In more simple terms PA is a phospholipid that makes up a small percentage of the total phospholipid pool in the body. As such, it is a constituent of all cell membranes. Relevant to its role in bodybuilding and sports nutrition, PA acts as an intracellular lipid second messenger that regulates the important signalling protein called mammalian target of rapamycin (mTOR).
Where Does Phosphatidic Acid Come From?
While there are three main pathways in the body which synthesize, there are also several natural sources in nature. These include soy and egg. These different sources of PA have varying degrees of unsaturated or saturated fatty acid chains and this can influence the behavior of PA. Specifically, it has been suggested that two saturated fatty acids will promote storage, but one saturated and one unsaturated fatty acid will promote signaling3.
Phosphatidic Acid Benefits
The interest in supplementation with PA stems from its role as stimulator of the mTOR pathway, which is also the same mechanism by which leucine and protein stimulate muscle growth. To date there have been two studies exploring the effect of supplemental PA on the response to a periodised resistance training program. One study conducted by researchers from Florida found that supplementing with PA in conjunction with a 4-day per week resistance training program over 8 weeks lead to a 12.7% increase in squat strength and a 2.6% increase in lean body mass, while subjects consuming placebo showed a 9.3% improvement in squat strength and a 0.1% change in lean body mass1.
The second study was conducted at the same institution but by different researchers and involved 28 subjects with an average age of 21 who also took part in an 8 week periodised resistance training program where they trained 3 times per week2. Compared with placebo, subject receiving PA exhibited a significant increase in lean body mass (+2.4 kg), cross sectional area (+1.0 cm), and leg press strength (+51.9 kg) over placebo.
In summary these two studies suggest that 8 weeks of supplementation with PA is likely to be beneficial in increasing lower body strength and lean body mass.
Phosphatidic Acid Recommended Dosages & Timing
Both of the above studies used a daily dose of 750 mg of PA2, 3.
Phosphatidic Acid Supplements
Supplemental forms of PA can be derived from either soy or egg sources, however, studies have shown that soy based sources of PA result in a stronger stimulus of mTOR2. Hence this is the source most commonly used in supplements.
Phosphatidic Acid Safety
Even though the activation of mTOR is considered a key regulator of survival in human cancer cells, there are no concerns regarding the safety of oral supplementation with PA.
1. Hoffman JR, et al. Efficacy of phosphatidic acid ingestion on lean body mass, muscle thickness and strength gains in resistance-trained men. Journal of the International Society of Sports Nutrition. 2012;9:47.
2. Joy JM, et al. Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy. Nutrition & Metabolism. 2014;11:29.
3. Foster DA. Regulation of mTOR by phosphatidic acid? Cancer Res. 2007;67:1–4.