I’ve been talking about glycine for years. It is one of my favorite amino acids. The reason why is does what it did for you is as follow:
Glycine is an inhibitory amino acid, it acts a lot like GABA in that it decreases neural activity. It calms your brain down by having your neurons firing slower. It helps put you in parasympathetic/rest and recover mode.
It will thus decrease anxiety as well as facilitate recovery from training, mostly neurological recovery.
The problem with neurological recovery occurs when your neurons keeps firing super fast for hours after your workout. During the session your nervous system is firing on all cylinders, especially if the lifting is heavy (or explosive, or high skill). Which is needed to perform. But if it stays that way for hours and hours after your workout you risk what we call “CNS fatigue” (which isn’t really CNS fatigue). I explained this in depth in a previous “Question of Strength” column. But most of the time"CNS fatigue" is a temporaty resistance of the adrenergic receptors from being overstimulated (they are kept turned on when the nervous system stays amped up for hours) making you resistance to your own adrenaline thus having less energy, drive, motivation, confidence, etc.
The faster your can “shut down” your brain after ypur workout, the less negative impact it will have on the nervous system.
Glycine will put you more easily in parasympathetic mode, decreasing adrenaline levels and also cortisol levels. All of that helps your recover, allows you to maintain higher testosterone levels over the long run, build more muscle, retain less water,etc.
On top of that glycine is, with leucine, the amino acid that has the greatest impact on mTOR activation. Activating mTOR is the key to trigger muscle growth, the more you can activate it during and after your workout, the more muscle you can build.
So yes, glycine is an awesome amino acid, and one I have been using for over 13 years.
HOWEVER in about 15-20% of the population it can have paradoxical/opposite effects. In individuals with too much glutamate (very emotional people, with tons of mood swings) glycine becomes excitory instead of inhibitory.
As a type 3, especially one who likes to lift heavy, glycine will be the best supplement. Because type 3’s main problems are an overactivity of the CNS along with excess cortisol production. They also recover badly from heavy workouts. Glycine will help with all of these.