There is 6g of hydro whey providing 5.5g of protein (~90%) and 3g added leucine for a total of 9g in the mTOR matrix as per the label.
Yep. Here's an old post of mine on the subject (sorry for any repetition with Adizzle1's post):
"Here's the study on various doses of whey in combination with leucine and BCAAs:
https://www.ncbi.nlm.nih.gov/pubmed/24284442
Doses/combinations:
-25g Whey Protein (3g leucine)
-6.25g Whey Protein (0.75g leucine)
-6.25g Whey Protein (added leucine to 3g)
-6.25g Whey Protein (added leucine to 5g)
-6.25g Whey Protein (added leucine to 5g; from added BCAAs instead of just added leucine)
Interestingly, Phospho-mTOR was increased at 1.5 hours in the Whey 25g, Whey 6.25 (3g l) and Whey 6.25 (5gl), but not in the Whey 6.25g or Whey (3g l; BCAAs). The study, along with others, have shown that a suboptimal protein dose (6.25g whey) supplemented with leucine (3g total) can stimulate postprandial MPS rates equivalent to that of 25g whey (with 3g leucine total).
The discussion of the study said this:
Because BCAAs share a common intestinal transporter, differences in amino acid appearance profiles between W6+BCAAs and W6+High-Leu treatments likely represents antagonism between BCAAs for uptake from the gut, which is congruent with data showing that isoleucine and valine compete with and can impede leucine absorption (47). The same effect could be true for the transsarcolemmal BCAA transport because BCAAs share the same transporter at that site (48).
There's also another study that showed increasing the leucine content of EAAs (from 1.87g to 3.5g) taken intra-workout increased post-workout muscle protein synthesis by 33% compared relative to the lower leucine content:
Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis
There's also a study showing that a combination of 6g EAAs and ~40g carbs taken intra-workout was able to improve strength and fat-free mass by more than EAAs or carbs alone, with no significant difference in fat (all groups lost fat):
https://www.ncbi.nlm.nih.gov/pubmed/16456674
There's also some interesting research on Whey Protein Hydroslate (WPH):
Buckley et al. examined whether hydrolyzed whey protein isolate speeds recovery more effectively than intact whey protein isolate following eccentric exercise [21]. The subjects performed 100 maximal eccentric contractions of their knee extensors and then consumed either 25 g of hydrolyzed whey protein isolate or intact whey protein isolate. Interestingly, peak isometric torque was recovered fully in 6 h in the whey protein hydrolysate group, while it remained suppressed in the intact whey protein group.
The results revealed that whey protein hydrolysate ingestion induced significant increases in skeletal muscle glycogen levels compared with other protein sources or BCAA.
Thus, whey protein hydrolysate appears to enhance the effects of carbohydrate ingestion on post-exercise muscle glycogen resynthesis. Whether whey protein hydrolysate stimulates muscle glucose uptake and glycogen resynthesis in athletes remains to be determined.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2761917/
This makes the pairing of carbs with WPH (over BCAAs) particularly interesting, and, referring back to the low-dose whey + lecuine study, it seems very possible that you can get away with a lower dose of WPH with added leucine to 3-5g total.
With that in mind, I like either 6-10g EAAs with leucine content added to total 3-5g, or ~6g WPH with leucine content added to 3-5g total, plus ~40g carbs (I typically go with Gatorade powder since it's very affordable and can be used to flavor bulk ingredients) intra-workout.
With the above reserach in mind, I do not think that drinking only BCAAs intra-workout is ideal, as you also want EAAs, and 3-5g leucine of course. Also, it appears that sometimes you don't want a ton of BCAAs, just a lot of leucine and a "sufficient" amount of the other BCAAs and EAAs. The WPH provides these EAAs and BCAAs (along with some leucine of course), and the additional leucine brings the total leucine content into that ideal 3-5g range.