Clinical Studies Ingredients
- HgH Amino Acids Blend

These Research Studies on the Ingredients
Prove that GHR Platinum Supplements Really Work

Dr. LE Dorman, MD - Growth Hormone / Amino Acid Blend
Author of "The Methusaleh Factor"

As we age, our body stops producing an adequate supply of HGH amino acids. Out of the 191 amino acids in the Growth Hormone chain, GHR PLATINUM replenishes the body with the needed blend of Stacked HGH Amino Acids in the Right Ratio and Molecular Weight that helps Stimulate and Restore the Release of your body’s own natural Growth Hormone. Many substances stimulate the release of Growth Hormone from the pituitary gland. Amino acids ( from HGH chain ), drugs and exercise are among the provocateurs." ( Page 35 )

AMINO ACID: ARGININE

The Amino Acid - ARGININE works in two key ways in the body:

1. It is a precursor used to make other compounds. The first of these functions is that it works by converting into the special compound Nitric Oxide. This substance plays a pivotal role in various activities of metabolism in the body. These include the management of the flow of blood, various cellular activities of the Mitochondria to produce energy, and sending communication signals between the cells.

Nitric Oxide works by dilating and relaxing blood vessels. So it functions as a Vasodilator. This improves the circulation of the blood throughout the whole body. This allows more necessary nutrients from food and supplements, along with oxygen in the blood to reach the many organs, muscles, tissues and cells. This function also helps to lower high blood pressure. As a result of these activities, ARGININE  helps support a healthy Heart Function. Thus, it can be beneficial in alleviating related conditions, including Hypertension, diseases of the Circulatory System, Angina and Erectile Dysfunction ( ED ).

Meanwhile, Nitric Oxide also assists the body, by helping to remove toxic waste products from both the Liver and the muscles, which are produced from metabolism. Specifically, these include Lactate and Ammonia. The result of removing these waste substances quickly is that it helps the muscles, and the whole body, to recover more rapidly from physical exercise and strenuous workouts.

2. ARGININE also helps the body to create Proteins. Additionally, it helps support a healthy Immune System Function. Furthermore, it is also used to break-down sugars ( glucose ). Therefore, it might help improve a condition called Insulin Sensitivity. There are some research studies which indicate that it might then be beneficial to help people who suffer from Type 2 Diabetes.

One of the symptoms of aging is that our bodies sometimes do NOT create enough Arginine. Or our bodies simply
do NOT produce it very well. Often it is necessary for older people to obtain more Arginine by using supplements.

There have been numerous clinical studies by scientists over the past thirty years, regarding the Amino Acids of ARGININE
and LYSINE. They repeatedly show that increasing the amounts of these two particular amino acids boosts the production of
Growth Hormone ( GH ) and then its release into the body. Both of these amino acids are included in the GHR PLATINUM
Hgh Releasers products. Here are some of these studies which prove that ARGININE is a Growth Hormone Releaser ( GHR ).

Growth Hormone Responses to Varying Doses of Oral Arginine

https://pubmed.ncbi.nlm.nih.gov/15809017/

"5 and 9 grams of oral ARGININE caused a significant ( Growth Hormone ) GH response"

Growth Hormone, Arginine and Exercise

https://pubmed.ncbi.nlm.nih.gov/18090659/

"Most studies using oral ARGININE have shown that ARGININE alone increases the resting Growth Hormone levels at least 100%"

Acute Effect of Amino Acid Ingestion and Resistance Exercise
on Plasma Growth Hormone Concentration in Young Men

https://pubmed.ncbi.nlm.nih.gov/9063764/

Sixteen men completed four trials at random as follows:

( Trial A ) Performance of a single bout of resistance exercise preceded by placebo ingestion ( Vitamin C );

( Trial B ) Ingestion of 1,500 mg L-ARGININE and 1,500 mg L-Lysine, immediately followed by exercise as in Trial A;

( Trial C ) Ingestion of amino acids as in Trial B and no exercise;

( Trial D ) Placebo ingestion and no exercise.

Growth Hormone ( GH ) concentrations were higher at 30, 60, and 90 min during the ( two ) exercise trials ( A and B ) compared with the resting trials ( C and D ). No differences were noted in Growth Hormone [ GH ] between the exercise trials.

It was concluded that ingestion of 1,500 mg ARGININE and 1,500 mg Lysine immediately before resistance exercise does not alter exercise-induced changes in Growth Hormone [ GH ] in young men.

However, when the same amino acid mixture ( 1,500 mg ARGININE and 1,500 mg Lysine ) is ingested under basal conditions, the acute secretion ( release ) of [ Growth Hormone ] GH is increased.

A Study of Growth Hormone Release in Man After Oral Administration of Amino Acids

https://pubmed.ncbi.nlm.nih.gov/6790230/

"A study was carried out in [ fifteen ] 15 male volunteers to evaluate qualitatively the secretion of growth factors following stimulation by oral amino acids. The results showed that oral administration of a combination of two amino acids ( 1,200 mg 1-Lysine plus 1,200 mg 1-ARGININE ) provoked a release of Pituitary Somatotropin { related to GH } and Insulin."

"This phenomenon was reproducible and the growth hormone secreted in response to this stimulation had biological activity ( as demonstrated by a radioreceptor assay and somatomedin induction ). The effect appeared to be specific to the combination of the two amino acids."

Increased Human Growth Hormone Following Oral Consumption
of an Amino Acid Supplement: Results of a Randomized,
Placebo-Controlled, Double-Blind, crossover study in Healthy Ssubjects

https://pmc.ncbi.nlm.nih.gov/articles/PMC6732240/

"It is well established that intravenous (IV) administration of some amino acids results in significantly increased HgH secretion. Such studies prompted testing of oral amino acids supplements ( primarily ARGININE, Lysine & Orthinine )
to stimulate HgH secretion."

AMINO ACID: LYSINE

L-LYSINE is one of the eight ( 8 ) "Essential" Amino Acids. These are those which our bodies are NOT able to make. Thus we have to get them from protein foods we eat. Or we have to obtain them from supplements that contain them in forms which our bodies can readily digest and use.

LYSINE is one of the critical amino acids which is needed to make the other proteins in the body. It is vital to create muscle tissues, and to produce hormones, enzymes and anti-bodies. It also plays a vital role in the absorption of the Mineral Calcium, while it helps to reduce the loss of calcium in urine. It also lowers levels of Cholesterol.

Like the amino acid GLUTAMINE, it also assists in healing and repairing of body tissues and cells and recovery from wounds. As a Binding Agent, it works to help increase the number of new cells in a wound that is healing. Together with the amino acid GLYCINE, it is also required to create Collagen, which is used to form hair strands, skin, nails and the various connecting tissues in the body.

It is a precursor to L-Carnitine, derived from amino acids, and found in most of the cells in the body. This is important for the proper functioning of the Nervous System. Lysine is also a precursor for the compound L-Carathine which is also necessary to maintain a healthy Nervous System Function.

Carnitine transports LONG-CHAIN FATTY ACIDS across the cells Mitochondria and then burns them to produce usable energy for metabolism. Afterwards it eliminates the toxins produced by the metabolic processes out of the cells. Lysine is also vital for normal physical growth. Thus, a deficiency in the amount of Lysine in the body can cause various health problems and conditions, including slow physical growth, nausea, dizziness and fatigue.

There have been numerous clinical studies by scientists over the past thirty years, regarding the Amino Acids of ARGININE
and LYSINE. They repeatedly show that increasing the amounts of these two particular amino acids boosts the production of
Growth Hormone ( GH ) and then its release into the body. Both of these amino acids are included in the GHR PLATINUM
Hgh Releasers products. Here are some of these studies which prove that LYSINE is a Growth Hormone Releaser ( GHR ).

A Study of Growth Hormone Release in Man After Oral Administration of Amino Acids

https://pubmed.ncbi.nlm.nih.gov/6790230/

"A study was carried out in [ fifteen ] 15 male volunteers to evaluate qualitatively the secretion of growth factors following stimulation by oral amino acids. The results showed that oral administration of a combination of two amino acids ( 1200 mg 1-LYSINE plus 1200 mg 1-Arginine ) provoked a release of Pituitary Somatotropin { Growth Hormone } and Insulin."

"This phenomenon was reproducible and the growth hormone secreted in response to this stimulation had biological activity ( as demonstrated by a radioreceptor assay and somatomedin induction ). The effect appeared to be specific to the combination of the two amino acids; neither of the amino acids demonstrated appreciable stimulating activity when administered alone, even at the same doses. 

Acute Effect of Amino Acid Ingestion and Resistance Exercise on Plasma Growth Hormone Concentration in Young Men

https://pubmed.ncbi.nlm.nih.gov/9063764/

"Sixteen men completed four trials at random as follows:"

( Trial A ) Performance of a single bout of resistance exercise preceded by placebo ingestion ( Vitamin C );

( Trial B ) Ingestion of 1,500 mg L-Arginine and 1,500 mg L-LYSINE, immediately followed by exercise as in Trial A;

( Trial C ) Ingestion of amino acids as in Trial B and no exercise;

( Trial D ) Placebo ingestion and no exercise.

"Growth Hormone ( GH ) concentrations were higher at 30, 60, and 90 min during the ( two ) exercise trials ( A and B ) compared with the resting trials ( C and D ). No differences were noted in Growth Hormone [ GH ] between the exercise trials. It was concluded that ingestion of 1,500 mg Arginine and 1,500 mg LYSINE immediately before resistance exercise does not alter exercise-induced changes in Growth Hormone [ GH ] in young men."

"However, when the same amino acid mixture ( 1,500 mg Arginine and 1,500 mg LYSINE ) is ingested under basal conditions, the acute secretion ( release ) of [ Growth Hormone ] GH is increased."

Increased Human Growth Hormone Following Oral Consumption of an
Amino Acid Supplement: Results of a Randomized, Placebo-Controlled, Double-Blind, Crossover Study in Healthy Subjects

https://pmc.ncbi.nlm.nih.gov/articles/PMC6732240/

"It is well established that intravenous (IV) administration of some amino acids results in significantly increased hGH secretion. Such studies prompted testing of oral amino acids supplements ( primarily Arginine, LYSINE and Orthinine ) to stimulate hGH secretion."

AMINO ACID: GLUTAMINE

GLUTAMINE is a vital amino acid that supports healthy Brain Function. It is needed for the creation of both RNA and DNA. Growth hormone stimulates a process in the body which is known as "NeuroGenesis". This is the way in which new neuron cellss in the brain are made. It also supports the maintenance and functioning of existing brain cells.

In a similar way, the levels of Growth Hormone ( GH ) also affect the levels of NeuroTransmitters in the brain. These are critical for many functions, processes and activities in the body. In particular, GLUTAMINE is a powerful amino acid that is also precursor for the making of the NeuroTransmitters GABA and Glutamate. These brain NeuroTransmitters also help to regulate and support various Cognitive Functions, including mood, concentration and memory. GABA is also included in the formulation of the GHR PLATINUM products as one of the HgH Enhancers Complex.

Researchers know that even small dosages of supplementing with extra GLUTAMINE can stimulate a noticeable increase in the levels of Growth Hormone ( GH ) in the body. Various clinical studies have shown that using even just 2 mg of this powerful amino acid could temporarily raise the levels of Human Growth Hormone ( HGH ) by as much as 78%.

GLUTAMINE is also precursor to making the amino acid ARGININE - which is proven clinically to promote the increase in production and secretion of Growth Hormone ( GH ) in the Pituitary Gland. So when you consume more proteins which contain Glutamine, or you increase your intake with supplements, you allow your body to raise the levels of ARGININE and the NeuroTransmitters GABA and Glutamate. And there are many research studies which have already shown that both Arginine and Glutamine stimulate the release of Growth Hormone.

How does GLUTAMINE work to promote a release of the Growth Hormone? The NeuroTranmitter Glutamate has a significant part in stimulating the Somatotrophs in the Pituitary Gland. These are the special cells in the Pituitary that actually signal the production and secretion ( release ) of Growth Hormone ( GH ).

There is also a link between Fat Burning in the body and Growth Hormone ( GH ). Growth Hormone helps in the breaking-down of body fats, by a process that is called "Lipolysis". This is how fats and other lipids are digested and then converted to FATTY ACIDS. There is also a similar connection between the metabolism of Carbohydrates and Growth Hormone. This has a direct relationship to levels of blood sugar levels. Thus GLUTAMINE plays a significant role in the Digestive Function and also the subsequent conversion of Starches, Sugars and Fats into usable energy through healthy activities of body metabolism.

Since this important amino acid has a significant affect on levels of body fat, sugar and weight loss, it is important to maintain adequate  levels of both GLUTAMINE ( and ARGININE ). Both of these amino acids are involved in stimulating the production and release of your own natural Growth Hormone ( GH ). The result provides various health benefits to our bodies and minds, physically and mentally.

Moreover, improving the metabolism of both Carbohydrates and Fats in the body, you can achieve healthy weight loss, or simply keep a proper and healthy weight balance. The results will then cause a corresponding increase in the production and release of ( more of ) your own Human Growth Hormone ( HGH ). What is the connection between BODY FAT and HgH levels in the body?

Research studies repeatedly indicate and prove that high levels of BODY FAT, especially BELLY FAT, will decrease, or inhibit, both the production and then the release of Growth Hormone ( GH ). The amount of FAT ( Adipose Tissue ) that men and women carry around in their bodies, especially in their BELLIES, significantly impacts the production of Growth Hormone ( GH ) in a negative way that is made and released from their Pituitary Glands. So if you can lose that extra weight, particularly any BELLY FAT, you can then actually raise the production and release of more of your HGH. The GHR PLATINUM products can help you to do just that.

GLUTAMINE is also the most abundant amino acid which is in the blood and in fluids of the body. There it has several important functions. It is used to create proteins, produce energy, and help with detoxification and removal of waste products, such as Ammonia, from metabolism.

Additionally, this amino acid is needed for a healthy Digestive Function ( as explained above ) and good Intestinal Health. It also supplies energy for White Blood Cells and for growth and maintenance of certain cells in the Intestines. There, this amino acid helps to maintain the barrier which is between the inside of the Intestines and the rest of the body. In this way, it enables you to maintain a healthy gut. This protects against getting what is called a "Leaky Gut". So it works to support a healthy Immune System Function, which helps to protect you from infection, sickness and disease.

Deficiencies of this amino acid can occur when a person is experiencing a lot of stress, or has an illness or severe injury. In those times, the body actually needs an abundant supply of Glutamine for healing and recovery from wounds. Specifically, the body requires it for repairing damaged tissues and cells.  Consequently, if the body needs more Glutamine than it can make on its own, it must get it elsewhere. As a result, the body might then break down muscle proteins, in order to release more of this amino acid. This is what happens often times when a person gets sick or injured.

When a person is under high levels of stress, the body produces much more the Hormone CORTISOL. This is the reason that it is called the "Stress Hormone". Is there a link between HgH levels in the body and stress? Health researchers have discovered that  CORTISOL can inhibit the production of Growth Hormone. Therefore, when you lower the amount of stress you have in your body,
with sufficient amounts of Glutamine, you can also reduce the levels of CORTISOL which block the production and release of that very Growth Hormone ( GH ) you need and want.

Here is one research study that shows an increase of GLUTAMINE causes an increase in Growth Hormone levels:

Increased Plasma Bicarbonate & Growth Hormone After Oral Glutamine Load

https://pubmed.ncbi.nlm.nih.gov/7733028/

"An oral GLUTAMINE load was administered to nine healthy subjects to determine the effect on Plasma Glutamine, bicarbonate, and circulating Growth Hormone concentrations.

"These findings demonstrate that a surprisingly small oral GLUTAMINE load is capable of elevating alkaline reserves as well as plasma Growth Hormone ( GH )."

AMINO ACID: GLYCINE

L-GLYCINE is the second most common amino acid that is used to make the various proteins of the body. It is the most abundant amino acid needed to create Collagen. Collagen is needed for the hair, nails, skin and various connective tissues throughout the body. This amino acid also assists in building bones, muscles ( and energy in the muscles, ) supporting a healthy Brain Function, as well as supporting healthy Patterns of Sleep.

Glycine is used to synthesize the TriPeptide Glutathione ( which is an AntiOxidant found in the cells ). This compound is made from the 3 Amino Acids: Glutamic Acid, Cysteine, and GLYCINE. However, as we age, our bodies have less of an ability to make this important AntiOxidant. Therefore, we most likely we need to obtain more of it by taking supplements as we grow older.

The AntiOxidant Glutathione helps the body to prevent damage and disease to tissues, cells and the organs ( particularly the Liver ), which Free Radicals can cause. When damaged portions of the Liver form Fibrous Tissues, they can become scarred. Or the Liver can become diseased through build-up of excessive fat ( "Fatty Liver" ), alcohol consumption and various immune attacks.

Glycine also works as a brain NeuroTransmitter. In this function, it works in the processing of motor and sensory information, which enables movement, vision and hearing. It also works by helping to calm the Central Nervous System. And just like the amino acid  Glutamine, the ability of our bodies to make it, can become negatively impacted during times of stress, sickness or injury. Therefore, it is necessary to help repair tissues and cells and for healing of wounds.

Finally, this amino acid participates in the Digestive Process. It helps to digest fats by managing the release of Bile Acids from the Gall-Bladder into the Small Intestine. At the same time, it also works as a "Glucogenic Amino Acid", that enables the Liver to convert it into Glucose ( Sugar ).

There have been numerous clinical studies that prove the connection between increasing the amount of Glycine in the body and a related boost in the levels of Human Growth Hormone ( HgH ) in the body. Here are some of them:

Glycine Stimulated Growth Hormone Release in Man

https://pubmed.ncbi.nlm.nih.gov/7376793/

"The influence of GLYCINE, the simplest amino acid, on Pituitary Function has been investigated in the present study. Different doses ( 4, 8, or 12 grams ) of Glycine were intravenously infused over 15 or 30 min in normal subjects.

The dose of 4 or 8 grams [ of ] Glycine induced a significant increase in serum [ Growth Hormone ] GH; however, a more pronounced and significant increase in serum [ Growth Hormone ] GH levels was observed after infusion at a dose of 12 grams [ of ] GLYCINE."

"The present data suggests that GLYCINE might play an important role in the control of Hypothalamic - Pituitary function."

Stimulatory Effect of Glycine on Human Growth Hormone Secretion

https://pubmed.ncbi.nlm.nih.gov/622050/

"GLYCINE was administered orally to 19 non-Obese normal subjects and 12 subjects with partial gastrectomy. In the normal subjects, a clear and significant increase of serum Human Growth Hormone ( hGH ) level was observed."

"The facts demonstrated that Glycine is one of the stimulatory agents inducing the Pituitary Gland to secrete HgH."

The Effect of Glycine Administration on the Characteristics
of Physiological Systems in Human Adults: A Systematic Review

https://pubmed.ncbi.nlm.nih.gov/37851316/

"Functional decline of Physiological Systems during Aging leads to Age-Related Diseases. Dietary Glycine increases healthy lifespan in model organisms. and might decrease inflammation in humans, suggesting its gero-protective potential. This review summarizes the evidence of Glycine administration on the characteristics of eleven Physiological systems in adult humans."

"The Nervous System demonstrated the most positive effects, including improved psychiatric ( mental ) symptoms from longer-term Glycine administration; longer-term Glycine administration improved sleep in healthy populations."

Reduced Plasma Glycine Concentration in Healthy and Chronically Diseased
Older Adults: a Marker of Visceral Adiposity { FAT }?

https://pubmed.ncbi.nlm.nih.gov/38616018/

"Previous studies have shown that a reduced plasma concentration of the amino acid [ GLYCINE ] GLY is associated with intra-abdominal obesity, but the mechanism remains unclear. This study aimed to investigate whether lower plasma
[ GLYCINE ] GLY concentrations in older adults are independently associated with ( visceral ) Adiposity { Condition of being FAT }, age, sex, presence of chronic disease, & glucose intolerance, and whether they are caused by a reduced [ GLYCINE ] GLY Whole-Body Production ( WBP ) and/or increased GLY disposal capacity."

"We studied 102 older adults ( 47 males / 55 females ). We assessed body composition and Visceral Adipose Tissue ( VAT ). The strong association between lower plasma [ GLYCINE ] GLY and increased { Visceral Adiposity Tissue } VAT mass in older adults was independent of age, sex, body weight, lean mass or body mass index, and the presence of COPD."

Reduced plasma [ GLYCINE ] GLY in older adults can be considered a marker of Visceral Adiposity, independent of sex, age, body composition, presence of chronic disease, and whole-body GLY production or clearance.

AMINO ACID: TYROSINE

The Amino Acid - TYROSINE is made from Phenylalanine, one of the 8 "Essential" Amino Acids. Consequently, we must consume plenty of Phenylalanine in our diets, or else we have to obtain it from taking supplements. Thus, if we are lacking in Phenylalanine, we will also be deficient in Tyrosine also.

Tyrosine plays a part in building proteins. In this way, it participates in the production of the various Thyroid Hormones ( Thyroxin ), which help regulate Metabolism, Adreno-Cortical Hormones, Melanin ( a pigment found in the hair, skin and iris of the eyes ), Enzymes, and various NeuroTransmitters in the brain.

The NeuroTransmitters in our brains relate to our various Cognitive Abilities, such as mood, focus, concentration, memory, working memory, cognitive flexibility ( ability to switch tasks or change thoughts ) and following instructions.

Thus this amino acid is a precursor for the NeuroTransmitters / Hormones - Dopamine, Epinephrine, Norepinephrine,  Adrenaline and Noradrenaline. Each of these compounds can affect the secretion of HgH in the Pituitary Gland.

Dopamine is critical for our mental functioning and mood. It regulates the reward and pleasure centers. This important
brain substance is also vital for memory and motor skills.

Adrenaline and Noradrenalin are hormones that are responsible for what is called the "Fight-or-Flight Response" in stressful situations. They enable our bodies to stand and fight, or flee and run - from a perceived or actual attack or harm.

In these ways, this particular amino acid helps to balance the affects of excessive physical and mental stress. When we are under a high level of stress, we often have difficulty thinking clearly and remembering things. Research studies have shown that supplementation with Tyrosine helped to improve such Cognitive Ability. Numerous other studies which have been conducted, proved that Tyrosine reduces anxiety and stress, and assists people to be more mentally alert.

Similarly, Tyrosine has a role in the making of "Enkephalins". These are special substances in the brain which provide pain-relieving effects to the body. They are critical to the healthy functioning of our brains, because they are responsible for transmitting nerve impulses and signals, and prevent conditions such as depression.

Additionally, this amino acid also plays a role in the regulation of Blood Pressure, and also helping to reduce BODY FAT ( which significantly lowers HGH production ). Finally, it also works an AntiOxidant, helping to protect the body from damage to organs, tissues, muscles and cells caused by Free Radicals.

There has been much research to discover how TYROSINE stimulates the Pituitary Gland to cause it to secrete ( more ) Growth Hormone ( GH ). This increased release of our GH, through the work of Tyrosine, may occur at particular times, especially when under stress.

One particular study found that it has a significant part in supporting increased levels of both HGH and IGF-1, particularly in conditions of high stress or during high-intensity workouts. Researchers think that it works by activating the Enzyme, called Tyrosine Kinase, which then acts in the capacity of a messenger, that the Pituitary Gland to start various metabolic activities linked to the production and release of Growth Hormone ( GH ).

Furthermore, various clinical studies have demonstrated that TYROSINE is even more effective at boosting the levels of Human Growth Hormone ( HgH ) - when it is combined with two other specific Amino Acids. So when TYROSINE is then combined with ARGININE and LYSINE, there is a greater increase in HGH levels, compared to using TYROSINE alone.

There is already much research that demonstrates elevating the levels of both ARGININE and LYSINE, particularly when these two amino acids are combined together, leads to a corresponding increase in the production and release of Growth Hormone ( GH ).

Behavioral and Cognitive Effects of Tyrosine Intake in Healthy Human Adults

https://pubmed.ncbi.nlm.nih.gov/25797188/

"The amino acid Tyrosine is the precursor to the catecholamine NeuroTransmitters Dopamine and Norepinephrine. Increasing Tyrosine uptake may positively influence catecholamine-related Psychological Functioning."

"We conducted a systematic review to examine the effects of Tyrosine on behavior and Cognition. Fifteen studies were reviewed. All studies except one involved Tyrosine loading during a single test session. In most behavioral studies, there were no significant effects of Tyrosine on exercise performance."

"In contrast, Cognitive studies employing neuro-psychological measures found that Tyrosine loading acutely counteracts decrements ( gradual decreases ) in working memory and information processing that are induced by demanding situational conditions such as extreme weather or cognitive load."

"The buffering effects of Tyrosine on Cognition may be explained by Tyrosine's ability to neutralize depleted brain catecholamine levels. There is evidence that Tyrosine may benefit healthy individuals exposed to demanding situational conditions."

Working Memory Reloaded: Tyrosine Repletes Updating in the N-Back Task

https://pmc.ncbi.nlm.nih.gov/articles/PMC3863934/

We tested the idea that the food supplement L-Tyrosine ( TYR ) repletes { provides / supplies } resources required for Cognitive-Control Operations. We investigated whether the “updating” ( and monitoring ) of Working Memory ( WM ) representations, a key Cognitive-Control Function, can be promoted by administering L-Tyrosine, the biochemical precursor of Dopamine ( DA ).

Interestingly, executive control has been considered to emerge from the interplay between cognitive stability ( defined as the maintenance of task-relevant representations ) and flexibility ( defined as the ability to adapt, update, and shift between informational states ) – two major, but partially antagonistic functions of cognitive control, (that are) related correspondingly to the PreFrontal Cortex ( PFC ) and the Striatum, which both are modulated by Dopamine ( DA ) - the precursor of which is L-Tyrosine (  TYR ).

The current study focused, for the first time, on the acute effect of L-Tyrosine supplementation on the updating (and monitoring) of Working Memory ( WM ) representations – a key cognitive-control function. We tested whether WM updating can be promoted by administering the food supplement L-Tyrosine (  TYR ). We investigated the link between L-Tyrosine supplementation and the monitoring of WM in healthy adults exposed to an oral dose of either L-Tyrosine (  TYR ) or a neutral placebo.

The present study is the first to demonstrate that Tyrosine supplementation promotes Working Memory ( WM ) updating. As expected, the more challenging 2-back condition was more sensitive to the effect of Tyrosine, which reinforces our suspicion that only tasks with considerable Cognitive Demands benefit from Tyrosine. As we have argued in the introduction, this may be because more demanding Cognitive Operations are more likely or more efficient to exhaust the available Cognitive Resources, which can then be repleted { provided / supplied } by Tyrosine.

Increased Human Growth Hormone Following Oral Consumption of an
Amino Acid Supplement: Results of a Randomized, Placebo-Controlled, Double-Blind, Crossover Study in Healthy Subjects

https://pmc.ncbi.nlm.nih.gov/articles/PMC6732240/

"Does an investigational amino acid supplement affect Hgh release? This was a Randomized, Placebo-Controlled, Double-Blind, crossover study that included 16 ( 12 males, 4 females ; Age 32 ±14 years ) healthy participants. All participants received both placebo and the amino acid supplement after an overnight fast and completed all study visits. Treatment order was randomized and each treatment was separated by a 1-week washout period."

"The primary outcome were the percent change in HgH from baseline to 120 minutes and the area under the curve of hGH over baseline. At 120 minutes, HgH levels increased by 682% ( 8-fold ) from baseline and were significantly higher than placebo.  In addition, a significantly higher mean AUC was observed for the amino acid supplement compared to placebo."

These results show that a single dose of the oral amino acid supplement was sufficient to significantly increase hGH levels in healthy adult males and females.

Tyrosine Promotes Cognitive Flexibility: Evidence From Proactive vs. Reactive Control During Task Switching Performance

https://pubmed.ncbi.nlm.nih.gov/25598314/

"Tyrosine ( TYR ), an amino acid found in various foods, has been shown to increase Dopamine ( DA ) levels in the brain. Recent studies have provided evidence that Tyrosine ( TYR ) supplementation can improve facets of Cognitive Control in situations with high Cognitive demands."

"Here we investigated whether Tyrosine ( TYR ) promotes cognitive flexibility, a cognitive-control function that is assumed to be modulated by Dopamine ( DA ). We tested the effect of TYR on proactive vs. reactive control during task switching performance, which provides a relatively well-established diagnostic of cognitive flexibility. In a Double-Blind, Randomized, Placebo-Controlled design, 22 healthy adults performed in a task-switching paradigm."

"Compared to a neutral placebo, Tyrosine ( TYR ) promoted Cognitive flexibility ( ie: reduced switching costs ). This finding supports the idea that Tyrosine ( TYR ) can facilitate Cognitive flexibility by repleting { filling / supplying } Cognitive resources."

Effect of Tyrosine Supplementation on Clinical and Healthy Populations
Under Stress or Cognitive Demands - A Review

https://pubmed.ncbi.nlm.nih.gov/26424423/

"Consuming the amino acid Tyrosine ( TYR ), the precursor of Dopamine ( DA ) and Norepinephrine ( NE ), may counteract decrements ( gradual decreases ) in neurotransmitter function and cognitive performance. However, reports on the effectiveness of Tyrosine ( TYR ) supplementation vary considerably, with some studies finding beneficial effects, whereas others do not. Here we review the available cognitive/behavioral studies on Tyrosine ( TYR ), to elucidate whether and when TYR supplementation can be beneficial for performance."

"In contrast, TYROSINE ( TYR ) does seem to effectively enhance Cognitive Performance, particularly in short-term stressful and / or Cognitively demanding situations. We conclude that TYROSINE ( TYR ) is an effective enhancer of Cognition, but only when NeuroTransmitter function is intact and Dopamine ( DA ) and/or Norepinephrine ( NE ) is temporarily depleted."