Understanding Post-Workout Nutrition

Phil Learney

Written by Phil Learney - Strength & Conditioning Expert

The combining of various proteins, much like the differing rates of carbohydrate metabolism, allows us to utilize different absorption and uptake rates,

thus modulating the postprandial (after ingestion) metabolic responses.

Utilising different molecular forms of protein, we can combine varying rates of absorption and support muscle protein synthesis for longer, whilst delivering the desired high plasma response of amino acids post workout.


Bioavailability (BA), with the exception of intravenous administration (direct into a vein) is of importance as it indicates the fraction of what we ingest orally that is actually available for absorption, use and storage intra-cellularly (1,2)

To analogise, it’s like having a wallet with £100 in it but £50 of it is the wrong currency. It’s still £100, but only half of it is usable.

How much of the protein we ingest is usable and how much do we excrete?

A low bioavailability in a supplement means the amount that actually reaches the systemic circulation for absorption (what you can spend) is significantly less than the amount stated on the label.

The quality of a supplement is partly defined by this statistic, but unfortunately it isn’t an obligatory statistic made available to the consumer.

PhD Nutrition have combined various molecularly different proteins to offer a post workout product that extends beyond simply the higher initial concentration of amino acids we typically receive from the faster whey and isolate derivatives.

The idea is to create a higher concentration of plasma essential amino acids post workout that is associated with a higher muscle protein synthesis (MPS) (3,4), concurrently then providing a steady release of amino acids that keeps that level of muscle protein synthesis high over a more prolonged period of time.

Typically the faster the absorption, the quicker therefore the lowering.

Whey and whey isolate taken independently would classically require a whole food source to maintain this underlying level of synthesis beyond the window in which something so readily available would provide. This, after considering digestive turnover rates for many whole foods, leaves a series of questionable trade offs ideally best avoided.

Proteins can be termed as anabolic (regenerative) or anti catabolic (preventative of degeneration) both critical if we are to build whilst also sparing muscle tissue. The latter releasing a slow steady state of amino acids into the bloodstream. The former a rapid influx. It’s important to understand this when we start to understand and categorise the different forms.

The four key ingredients in PhD Tricellar Whey™

  • Hydrolysed Whey Isolate

This is at the top of the tree. By hydrolysing the already rapidly absorbed whey isolate, it takes the long protein chains and breaks them down into small chain peptides, enabling faster digestion, absorption and utilization. This is a process
called enzymatic hydrolysis and is often referred to as ‘pre-digestion’

This takes the already high BA of the whey isolate and allows a faster gastric emptying time (passage through the gut)

  • Whey Isolate

This gives the concurrent yet more tapered rate of absorption. As mentioned this has an already high BA but the non-hydrolysed version has a slightly slower rate of passage into the circulation. This creates a lower peak of MPS and a slightly prolonged state of anabolic signaling.

  • Micellar Casein

Micellar casein is a ‘slower’ form allowing a prolonged period of elevated amino acids in the blood. Micellar casein is the only protein that has been shown to prevent the oxidative breakdown of muscle tissue during and post training. (5)

This allows it to be termed as anti-catabolic (anti degenerative)

Micellar casein forms a clot in the stomach that slows down its rate of gastric emptying (one of the influencing factors in rate of absorption). This slows down the amount of amino acids released into the small intestine before reaching the bloodstream.  This gives a prolonged and slow state

  • Micelle XL™ Casein

Micelle XL™ is a restructured form of micellar casein. The molecules are approximately three times the size of regular micellar casein. This slows the rate of absorption yet again and overlays a final speed of uptake and muscle protein synthesis.

The combination of the four proteins provide sufficient rates of anabolism and muscle protein synthesis immediately post workout whilst supporting these metabolic processes far beyond the normal absorption window.

Introducing MicelleXL™ - a U.K. first ingredient innovation

Written by Phil Learney


1 - Heaney, Robert P. (2001). "Factors Influencing the Measurement of Bioavailability, Taking Calcium as a Model". The Journal of Nutrition 131 (4): 1344S–8S.

2 - Srinivasan, V. Srini (2001). "Bioavailability of Nutrients: A Practical Approach to In Vitro Demonstration of the Availability of Nutrients in Multivitamin-Mineral Combination Products". The Journal of Nutrition 131 (4 Suppl): 1349S–50S.

3 - Greater stimulation of myofibrillar protein synthesis with ingestion of whey protein isolate v. micellar casein at rest and after resistance exercise in elderly men. The British Journal of Nutrition (2012).

4 - Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein. American Journal of Clinical Nutrition (2009).

5 - Boirie Y1, Dangin M, Gachon P, Vasson MP, Maubois JL. (1997). "Slow and fast dietary proteins differently modulate postprandial protein accretion". Proc Natl Acad Sci U S A. 1997 Dec 23;94(26):14930-5.

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