Amino acids and derivatives

EAAs, BCAAs, leucine, HMB, glutamine, citrulline. Which has an effect of its own, which is an expensive version of something you already eat, and why BCAAs still sell.

Loose amino acids are protein taken apart. That is the key to the whole category: you are almost always paying considerably more for a fraction of something you already have whole and cheaper in the tub next to it.

BCAAs: the clearest case of a product with no slot

The branched-chain amino acids — leucine, isoleucine and valine — are three of the nine essential ones. The commercial idea is that since leucine fires the anabolic signal, taking the three is enough. The problem is that a signal without material builds nothing.

The one context where something like this makes sense is prolonged fasting with training in the middle, and there the right answer is complete EAAs, not BCAAs.

EAAs: the version that does make sense, in a small slot

Complete essential amino acids do sustain protein synthesis: they are protein without the rest. The catch is the price, which per useful gram is usually three or four times that of a good whey concentrate.

• Dose: 10-15 g with a leucine content of 2-3 g.
• When they pay off: fasted training when you cannot tolerate a shake beforehand, or digestive problems that rule out whole protein.
• When they do not: on any normal day when you hit your protein from food. Which is most of them.

Leucine on its own

It has a real slot in plant-based diets with small servings and in older adults, where anabolic resistance raises the per-meal leucine threshold.

HMB

It is a metabolite of leucine. The ISSN devoted a position stand to it in 2013 with optimistic conclusions; what has happened since is that the large effects show up mostly in untrained people and in muscle-wasting situations, and shrink or vanish in people who already train.

Studied dose

3 g/day, split

The free acid form (HMB-FA) absorbs faster than the calcium salt; no clear advantage in outcomes.

Where there is a signal

Beginners, older adults, enforced rest

As a protector of lean mass rather than a builder.

Where there is not

Trained people with enough protein

This is why the AIS keeps it out of group A.

Glutamine

Citrulline and nitric oxide precursors

Citrulline raises blood arginine better than arginine itself, and with it nitric oxide production. It is the ingredient behind the pump sensation of pre-workouts.

• Dose with studies behind it: 6-8 g of citrulline malate, about 60 minutes before.
• What the evidence shows: Gonzalez and Trexler’s review finds mixed results; some studies see more repetitions in sets to failure, others see nothing. Small, inconsistent effect.
• What it does not show: that the pump you feel translates into more hypertrophy. That is a hypothesis, not a finding.
• Arginine alone has poor oral bioavailability: it is the worse version of the same idea.

The category at a glance