Basic Chemistry
Phosphatidyl Serine when consumed in food, for example egg yolks, or in a capsule provides about 20% of active Phosphorylated Serine. Each 100mg of Phosphatidyl Serine yields about 20mg of active phosphorylated serine following consumption. The bulk of the weight is derived from 2 fatty acids
In the intestinal tract, the various enzymes clip off the fatty acids, predominantly the unsaturated fatty acids. These fatty acids are not reassembled in the body to the stump molecule, rather different fatty acids are attached by the body to replace RI and R2.  The shaded glycerol molecule is very abundant in the body because it is found in all body fat and in dietary fats/oils in great abundance.

In brief, the Phosphatidyl Serine acts as a precursor molecule and is not the active form of this nutrient. In our tissues, the rate limiting step is the phosphorylation of the serine molecule. In contrast, Phosphorylated Serine (brand name, SERIPHOS®) provides the activated or Phosphorylated Serine in a chelate form of magnesium and calcium. In the local tissue, the Phosphorylated Serine is linked to glycerol and the appropriate fatty acids specific to each tissue, and is not linked to the fatty acids provided in the precursor Phosphatidyl Serine. Phosphorylated Serine (brand name, SERIPHOS®) is a pure product not derived from animal tissue. The serine is from vegetable sources and the phosphate is from a pure phosphate donor compound.