Delaying Physical and Mental Fatigue with Phenylalanines, Tyrosine

The consumer market is flooded with increased energy and mental alertness drinks and pills.  Phenylalanines claims to promote energy, mental alertness, elevates mood, and enhances concentration. 

I will attempt to explain how and why this works.

Without bringing back bad memories of College Biochemistry, here is the pathway (I’ll skip the enzymes for simplicity):

L-phenylalanine -> L-tyrosine -> L-DOPA –> Dopamine –> Norepinephrine –> Noradrenaline –> Epinephrine (or adrenaline)

L-phenylalanine (LPA) is one of the 20 common amino acids used to form proteins.

This is not to be confused with D-phenylalanine (DPA) or DL-phenylalanine (DLPA) which is marketed as a nutritional supplement for its supposedly analgesic and antidepressant activities.  A small amount of D-phenylalanine appears to be converted to L-phenylalanine.

You may have heard people suffering from depression frequently take “dopamine” and are told to consume Tyrosine supplements.

One has to simply look at the pathway above and you can clearly see where the supplement manufacturers are heading towards.  For example, you can’t buy generic dopamine off the shelf, but dopamine supplementation via tyrosine (and theanine, for example) has been marketed for mental alertness, increase feelings of well being, and offset physical and mental fatigue.

In a similar example, the old Sudafed formulation (with pseudoephedrine) can increase norepinephrine and thus act as a stimulant as well as being non-congested for better breathing in cold weather environments!  (** cough cough NHL Hockey Players cough cough **).  Because of the recent abuse of homemade crystal meth, drug stores have limited the purchase of pseudoephedrine products.

Tryptophan and serotonin has a sedative effect.  High amounts of Tryptophan can be found in turkey and warm milk… the 2 foods that allegedly can make you sleepy (whether it crosses the blood-brain barrier remains controversial).  Phenylalanine uses the same active transport channel as tryptophan to cross the blood-brain barrier, and, in large quantities, interferes with the production of serotonin. 

Thus Phenylalanine competes with tryptophan, and it explains why Tyrosine is one of the most popular ingredients in “mental alertness” supplements and drink such as as Vitalyze, PowerDrive, Red Bull, 5-hour energy shots, and countless others.

The products I have used in the past are:

1. SNAC’s Vitalyze contains DL-phenylalanine, L-Tyrosine, Ginseng, caffeine, B6.  Their old formulation did not contain caffeine.
2. Biotest’s Powerdrive contains L-Tyrosine, Phosphatidylcholine, DMAE, Ginkgo Biloba, B6. Powerdrive is hard to find (only in the UK) and also because Biotest is promoting their own product called SPIKE which is mainly Thiamine di(2-methyl-propionate) disulfide.
3. 5-hour energy shots contains Taurine, Tyrosine, L-Phenylalanine, and of course, Caffeine.  I like this “shot” because it gives me an alert feeling and improved mood without the jitters or shakes from too much coffee, espresso and caffeine!
4. Red Bull is another popular choice for athletes as it contains Taurine (not Tyrosine) and sugar.  It also contains Glucuronolactone which claims it detoxifies the body.   Elite athletes are addicted to this drink.  I know, I’ve seen cases disappear at the Rome Gala Meet!

Another source of phenylalanine is the artificial sweetener aspartame sold under the trade names "Equal" and "NutraSweet".  That, coupled with caffeine, and you wonder why people are addicted to Diet Coke?  In the U.S. and Canada, all products that contain aspartame must have the label "Phenylketonurics: Contains phenylalanine." as  a warning for people with the inability to metabolize phenylalanine.  This warning is for people with the genetic disorder, phenylketonuria.

The Red Bull sugar-free version also contains aspartame and sucralose in place of sucrose and glucose.

I hope this article helps you understand the nature behind “Energy” and “Mental alertness” drinks and pills.