Whey peptides are gradually gaining support from hard trainers who are well versed in muscular development. One of their avid drinkers, Hayato Aizawa, sat down with Mr. Hosoya of Megmilk Snow Brand Co., Ltd., who is involved in selling whey peptides, to discuss the unique appeal and effective ways to use them.

Aizawa: I started drinking whey peptides when I was in high school. When I tried them, I felt like I had a continuous pump throughout my training. I've been drinking them ever since.

Hosoya Whey Peptides are made by enzymatically hydrolyzing whey protein, so their advantage over other products is their rapid absorption. Peptides are further broken down into amino acids, and the absorption rate of peptides is said to be comparable to that of amino acids.

AizawaIs the absorption rate roughly the same as that of amino acids?

Hosoya Peptides vary in the number of amino acids they contain depending on the degree of degradation (Figure 1), but the majority of the peptides we handle are "tripeptides" with three amino acids and "dipeptides" with two amino acids. Tri- and di-peptides, as well as amino acids, have their own transporters in the small intestine (Figure 2), so they do not need to be decomposed before absorption. Therefore, it is believed that the absorption rates are roughly the same.

Aizawa: I was also recommended amino acids, but honestly, the price range of whey peptides is great for students like me to use on a regular basis. So, it's great news that the absorption rate is almost the same as amino acids (laughs). But, for example, assuming you've overcome the cost issue, how should you choose between whey peptides and amino acids?

(Figure 1)

(Figure 2)

Hosoya : In a simple comparison, whey peptides are likely to be superior in terms of amino acid composition. For example, BCAAs cannot supplement essential amino acids other than valine, leucine, and isoleucine. In contrast, whey peptides are made by finely chopping whey protein, so the amino acid composition remains intact. Compared to the same peptides based on casein or soy, whey peptides are richer in BCAAs (Figure 3), and they also contain the remaining six essential amino acids and 11 non-essential amino acids required for muscle synthesis.

Aizawa: The only difference is the molecular weight, but the nutritional value is the same. And it's fast-absorbing and relatively inexpensive, so it's got all the good points!

Hosoya Peptides can be thought of as a hybrid that combines the best features of proteins and amino acids, which are often compared.

Timing and amount of intake to maximize muscle synthesis

Aizawa: What about the timing of intake? I only take whey peptides during training. The "physical sensation" you mentioned earlier was the feeling of a sustained pump and the feeling of being able to maintain concentration until the very end.

Hosoya: Unfortunately, the relationship between peptides and the "physical sensation" of sustained pumping or sustained concentration is unknown. Generally, it is said that taking them after training, when muscle synthesis is at its peak, is the standard. However, there is ongoing debate as to whether taking them before or after training is better. While little has been said about taking them during training, since both muscle synthesis and muscle breakdown are at their peak during exercise, it could be argued that energy replenishment is necessary to prevent catabolism and to complete training to the end. Taking amino acids and peptides before and during training may be effective.

Aizawa: Along with the timing, I'm also concerned about the amount I take. I drink 40-60g of whey peptides per session, depending on the length of my training. I take 60g on leg days, when I mainly target half of my body. Since it takes a long time to train just one part of the body, I take a larger amount because I'm concerned about the concentration of amino acids in my blood. On days when I train other parts of the body, I usually take 40g.

Hosoya : First of all, we have to consider the burden that consuming too much protein can put on the kidneys. Generally, it's said that non-exercisers should consume 0.8g per kg of body weight, and athletes should consume 1.4-2.0g per kg of body weight. I would like you to use these as a guideline for your intake.

Aizawa: Bodybuilding may not be a world where normal standards apply (laughs). Even if you're told 2g per kg of body weight, it still feels like a small amount.

Hosoya : How much are you currently consuming?

Aizawa: I currently weigh 80 kg and aim for 3.5g per kg. Of course, I started with 2g at first, but I felt that it wasn't enough, so I adjusted it little by little, and now I feel like I've settled on this amount. However, when I talk to the bodybuilders around me, very few of them are satisfied with 2g. I think the harder you train, the more protein you need, so is there any research going on in this area?

There has been much research and discussion about the amount of protein needed to maximize muscle synthesis, and it is said that peak intake is around 20-30g per session.

Aizawa: Do you know why it's 20 to 30g?

Hosoya: Have you ever heard the phrase "leucine trigger theory"? This theory states that protein synthesis begins when the blood concentration of leucine, a BCAA, exceeds a certain threshold. Even now, several years after research began, no conclusion has been reached as to whether muscle synthesis increases as leucine concentrations increase after the threshold, or whether the switch for muscle synthesis is simply flipped once the threshold is exceeded. Nevertheless, since we know that leucine is essential for increasing muscle synthesis, it is believed that consuming 20 to 30 grams of protein is necessary to reach the threshold.

Aizawa : So leucine acts as a switch for muscle synthesis. But that doesn't mean that taking only leucine is enough, right?

Hosoya: That's right. Even if you press the switch, it won't actually work if the materials necessary for muscle synthesis aren't available. It makes sense to take amino acids other than leucine at the same time.

Aizawa: I had no idea there was another benefit to choosing whey peptides!

Hosoya : I would also like to point out that the muscle synthesis switch is not solely the responsibility of leucine. Progress is being made in elucidating the mechanism by which muscle synthesis is switched on through exercise such as training, and it is said that the hormone "insulin," which is secreted in response to carbohydrate intake, also has the function of switching on muscle synthesis.

Aizawa : If hard training activates muscle synthesis and requires more protein, then the benefits of whey peptides, which are quickly absorbed and highly nutritious, come into play.

Hosoya : It is believed that exercise and nutrients have a synergistic effect on muscle synthesis. In one experiment, leucine was administered directly into the bloodstream without exercise, and it was found that after a certain amount of time had passed after administration, the rate of muscle synthesis returned to the same level as before ingestion, regardless of the blood leucine concentration. This phenomenon is called the "muscleful effect," meaning that there is an upper limit to muscle synthesis. However, some believe that exercise raises this limit.

It seems that Aizawa 's experience isn't entirely based on assumptions. My whey peptide intake is also based on personal experience. I dissolved 42g of carbohydrates and 20g of whey peptide in a bottle that holds just over 1 liter and drank it twice during training. On leg days, I drank just 20g of whey peptide alone, and my performance improved, so I've continued. By "personal experience," I mean that compared to when I first started drinking only BCAAs, I no longer run out of gas mid-training. I was able to perform well until the final event and push myself to the limit. Even if other athletes started drinking it because "other athletes were taking it" or "it was recommended," I think they continue to drink it because of their personal experience. When you're immersed in training, you're always looking for information on what works best, but what's really important is that it fits your body. So I think I'll continue to trust my own "experience" and choose whey peptides.

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From GOLD'S GYM MANIA Vol.36

Keita Shimada talks about the appeal of whey peptides