During the first 3 months of life, most babies gain 170-225 grams a week!  During the next 3 months, their growth rate slows a bit, but they still gain about 140-170 grams weekly).

Protein is a key component of the nutrition babies need to fuel their growth.  Proteins are made up of amino acids—the building blocks that our bodies use to make their own unique proteins and other compounds.

Because nature designed human milk to perfectly suit the needs of growing babies, human milk is the best protein source for infants.  It has an unusually high proportion of essential amino acids, mainly because it is rich in a type of protein called alpha-lactalbumin. 

Alpha-lactalbumin—or alpha-protein for short—is easy to digest and rich in an amino acid called tryptophan. Tryptophan helps produce body chemicals that help to regulate mood, appetite, and sleep. Some investigators have reported that infants receiving a trytophan-fortified formula fell asleep faster than infants receiving standard formula. Wyeth's infant formula, which is rich in alpha-protein, provides a good source of tryptophan.

Because alpha-protein has relatively high levels of essential amino acids, a formula rich in alpha-protein can also have a lower level of total protein. A lower total protein level makes it easier for baby’s kidneys to process formula.

Although many standard infant formulas are whey-dominant like human milk, they have high levels of beta-lactoglobulin, a protein not normally found in human milk. Wyeth's infant formula with increased levels of alpha-protein and reduced levels of beta-lactoglobulin, has a composition closer to that of human milk.