Pre-workout supplementation has become increasingly popular in recent years. A huge variety of pre workout formulas are available for purchase and the vast majority are based around a core selection of supplements. Frequently, the volume of branded pre-workouts can be bolstered with cheap ‘fillers’ to give the illusion of value to the consumer. More recently the focus has been on ‘concentrated formulas’ with serving sizes of approximately 5 grams becoming common place. This article will discuss a no-nonsense and affordable pre-workout supplement formula that is designed to enhance pump, energy, endurance and focus.
Osagi (long-term MuscleTalk moderator and nutritional supplementation advisor) is typically recognised as the creator of the Osagi Stack, though he admits himself that he cannot take entire credit for the idea of stacking the different ingredients as he based it upon similar formulas used in many branded pre-workout products. As mentioned previously many of these products not only contain cheap ‘fillers’ but can be over-priced and contain low doses of active ingredients. However, by sourcing the ingredients from bulk suppliers and making your own pre-workout supplement a consumer can be sure they are getting value for money! So while Osagi might not have developed the stack, he did perfect it for the consumer.
The original ingredients and dosages of the Osagi Stack were:
- 3-5g Arginine Alpha Ketoglutarate (AAKG), Di-Arginine Malate or Arginine Ethyl Ester (AEE)
- 2g Creatine Ethyl Ester (CEE) or 3g Creatine Monohydrate
- 2g Taurine
- 1g Glucuronolactone
Naturally, over time the stack has changed, evolved and ultimately been refined and improved through a process of experimentation and feedback from many different trainers. As it stands now the updated stack consists of the following core ingredients:
- 4g Taurine
- 3g Tyrosine
- 1g Glucoronolactone
- 5g AAKG
Plus optional extras:
- Beta Alanine
- Citrulline Malate
- Dimethylethanolamine (DMAE)
- Acetyl-L-Carnitine (ALCAR)
As mentioned above, the purpose of this stack is to produce an enhanced ‘pump’ during training while simultaneously providing stimulatory and endurance enhancing benefits to a trainer. The above list of ingredients has therefore been carefully selected to provide all of these benefits in a single, synergistic stack. With this in mind this article will now discuss each of the ingredients in turn.
Arginine Alpha Ketoglutarate (AAKG) / L-arginine
Arginine is an amino acid that has numerous functions within the body. An important role arginine plays with regards to this stack is that it acts as a precursor to nitric oxide (NO) production (Andrew & Myer 1999, Harald et al 1994) which in turn relaxes blood vessels (Gokce 2004). NO plays an important role as a vasodilator. A vasodilator is a compound which causes vasodilatation, i.e. the dilating or relaxing of blood vessels. NO is produced in the body by an enzyme called nitric oxide synthase which converts the amino acid L-arginine to NO and L-citrulline. The NO causes the blood vessels to relax and increase in width, thus increasing your blood vessel’s ability to deliver blood to the muscles. This process causes your muscles to temporarily swell giving the ‘pumped’ look. This is obviously only a short term but can have both positive and negative physiological side effects. When the pump is there the trainer looks and feels bigger increasing their confidence. However, when the pump subsides the trainer may feel much flatter and smaller.
The main advantage of this improved blood flow is that more oxygen and vital nutrients are theoretically delivered to the muscle and more waste products (lactic acid, for example, which impedes performance) are removed from the muscle, potentially improving an athlete’s performance. There is also evidence to indicate that regular supplementation (12g daily) can increase strength in trained athletes (Campbell 2006).
The problem with supplementing with plain L-arginine is that little arginine actually makes it into the blood stream where it is actually used to produce the target nitric oxide. The body uses L-arginine for many purposes other than its role as a precursor of NO. When a trainer ingests L-arginine, a substantial amount of it will be destroyed in the liver by arginase. Arginase is an enzyme made in the body designed to remove excessive arginine. Obviously when supplementing with arginine the purpose is to elevate your arginine level so this enzyme poses a problem. While there are methods one could use to inhibit the arginase enzymes, these enzymes have other functions so this is not a route that should be advocated as rather than interfere with the enzyme we can bypass it entirely. A better route is to utilise alternative forms of L-arginine e.g. Arginine alpha-ketoglutarate (AAKG). AAKG is a salt formed by combining molecules of the amino acid L-arginine with molecules of alpha-ketoglutarate which will bypass the arginase enzyme increasing the amount available for NO production. AAKG was/is a key ingredient in products such as Gaspari Superpump 250 and BSN NO Xplode.
Taurine is the second most abundant amino acid in muscle behind glutamine. As a sports supplement, taurine is believed to have several important functions. It behaves similarly to creatine in that it can expand your muscle cells by causing the muscle cell to hold more water, i.e. ‘muscle cell volumisation’. For a trainer this may be of benefit as it can boost hydration possibly resulting in a higher rate of protein synthesis and muscle fullness.
There is limited research to support the use of taurine as a sports supplement with much of the evidence being anecdotal in nature. Li et al 2006 demonstrated that Zucker diabetic fatty (ZDF) rats on high-fat diets that were supplemented with taurine did not becoming overweight and had improved diabetes control. Research such as this has yet to be replicated in humans. The single study on human subjects showed daily administration of 1.5g taurine had no significant effect on insulin secretion or insulin sensitivity (Brøns et al 2004).
Taurine is also highly associated with improved mental focus and concentration which is why it is so often included in energy drinks. Again, research is limited in this area as typically taurine is tested as part of a ‘stack’ of ingredients in energy drinks (Alford et al 2001, Reyner & Horne 2002, Van den Eynde et al 2008). Within these studies, stacks containing taurine improved focus and concentration.
More information on taurine supplementation
Tyrosine is a non-essential amino acid formed from phenylalanine (the body can convert phenylalanine to tyrosine but it cannot convert tyrosine to phenylalanine). However, phenylalanine is an essential amino acid and if this is not available in sufficient quantities from ones diet then tyrosine can become an essential amino acid due to the lack of the precursor amino acid.
Tyrosine has become a popular sports nutrition supplement as it acts as a precursor for the manufacture of various hormones and neurotransmitters including, but not limited to, dopamine, dihydroxyphenyalanine (DOPA), norepinephrine and epinephrine. Tyrosine is thought to improve alertness and enhance cognitive performance. Avraham et al (1996) demonstrated in their study on mice that tyrosine supplementation improved some of the neurobiological disturbances associated with dietary restrictions without causing an increase in body weight. Should this type of effect transfer to humans then tyrosine supplementation would be beneficial in improving focus and performance during training particularly when the trainer is on a calorie restricted diet. Studies have also shown beneficial effects of tyrosine supplementation in humans. Deijen et al (1999) examined the effect of tyrosine supplementation on cognitive task performance on a group of 21 cadets during a demanding military combat training course. The group supplied with the tyrosine performed better on a memory and a tracking task than the control group supplied with the placebo.
These findings suggest that supplementation with tyrosine may, under operational circumstances characterised by psychosocial and physical stress, reduce the effects of stress and fatigue on cognitive task performance. As a result of this, a trainer may experience improved focus and mental performance during training. Tyrosine also has been linked as a potential weight loss aid (Hull & Maher 1990) however, this is not of relevance to this article.
Typically caffeine or ephedrine is a trainer’s stimulant of choice for pre-workout supplementation. The problem with compounds such as these is that they would counteract the previously discussed vasodilator (AAKG) in the stack as they are vasoconstrictors. A vasoconstrictor is the opposite of a vasodilator, in that they force blood vessels to tighten and constrict (which is what’s responsible for the increased blood pressure you may feel as a result of using these compounds, particularly the more powerful ones, such as ephedrine). The effect of using a vasoconstrictor at the same time as a vasodilator is that it tends to cancel out at least part (depending on the dosage of both supplements) of the pump enhancing effects you are aiming for, rendering that part of your stack at least partly obsolete. So this combination of stims, together with your NO stack, is best avoided if possible.
Glucuronolactone is a naturally occurring chemical compound produced from the metabolism of glucose in the human liver and is thought to increase endurance and improve reaction times, concentration and mental alertness. As a result of all these properties, glucoronolactone is also often included in ‘energy’ or stimulant drinks such as Red Bull. This substance in included as part of this stack as it doesn’t exert any vasoconstricting properties in the body so it won’t interfere with increased blood flow associated with AAKG.
Its exact effectiveness is unknown as previous research involves the study of energy drinks which also contain caffeine and taurine. It is therefore impossible to ascertain which compound was responsible for the enhanced benefits. The testing of the energy drinks did show this combination of ingredients (two of which are part of this stack) resulted in improved attention, reaction speed and aerobic and anaerobic performance (Alford et al 2001, Reyner & Horne 2002, Van den Eynde et al 2008). Research from the 1960s on animals supplemented with glucoronolactone in isolation showed improved endurance and stamina in rats over placebo, caffeine, glucose, fructose and glycogen (Tamura et al 1966, 1968).
Basic Stack Summary
The above is the basic Osagi stack. The purpose of this stack is to produce an enhanced pump while simultaneously providing stimulatory and endurance enhancing benefits to a trainer in a single, synergistic stack. However, the above protocol and stack may not suit every trainer. Don’t be afraid to experiment and add/remove ingredients and vary dosages as desired. Below are several such ingredients that may be useful additions depending on your goals.
Beta-alanine is an amino acid which is a popular addition to pre-workout formulas and is backed by relatively strong research as a performance booster. BA delays muscle fatigue, improves endurance, increases lean muscle mass and improves body composition. BA’s effects are achieved though its ability to indirectly increase the levels of carnosine in muscles.
When anaerobic metabolism occurs in muscles lactic acid is produced. The lactic acid then breaks down into hydrogen ions (H+) and lactate which causes a drop in the pH in the muscle. This build up of hyrogen ions in the muscle contributes to fatigue of the muscle. After beta-alanine is ingested it is converted to carnosine in the body. Carnosine is responsible for the buffering of H+ delaying musclular fatigue. (More on how beta-alanine works).
Research has demonstrated that when supplementing with 6.4g of BA daily for 4 weeks, muscle carnosine concentration increases by 40-60% (Harris et al 2006; Hill et al 2007) and for 10-12 weeks duration concentrations increased by 80% (Hill et al 2007). The effectiveness of BA to delay fatigue has been demonstrated in several published studies. Hill et al (2007) found that the total work completed before exhaustion in a cycle test increased by 13% after 4 weeks and a further 3% after 10 weeks supplementation of 6.4g of BA daily in comparison to those who had a placebo. Research on sprinters who supplemented with 4.8g a day produced increases in torque of 4-6% in the last two sets of a 5 set session of knee extensions. Kern & Robinson (2009) found that supplementing with 4g of BA daily resulted in decreased ‘shuttle’ times, increase lean mass and improved body composition. This contradicts pervious research (Kendrick et al 2008) which found supplementation with BA did not increase muscular endurance or body composition. Reasearch is still ongoing and concensus has yet to be reached but it appears BA supplementation is extremely uselful to endurance athletes so may be included as part of this stack particularly if endurance forms part of your training goals.
BA has no acute effect on performance and should be taken daily (4-6g daily). Again it can be included as part of this stack for convienience but must be taken on non training days seperately also. I would advise against taking all 4-6g at once as BA causes a tingling sensation on the skin which some people find disturbing so it is better advice to spread the dose into 2 to 3 doses during the day. Of course other people enjoy the tingling during the workout as it gives an indication that the stack is working providing a phycological boost to the trainer. Again, it is down to the individual trainers preferences.
Citrulline Malate (CM) is a compound formed from the amino acid citrulline (which is formed in the body during the urea cycle) and malate (a compound formed during the Krebs cycle). Again, it is thought that this supplement improves performance and reduces fatigue.
With regards to this pre-workout stack, CM can increase the level of arginine in the body (Dhanakoti et al 1990) and the trainer then benefits from the subsequent Nitric oxide (NO) benefits discussed above in the AAKG section of this article. Furthermore, during anaerobic and aerobic exercise the body produces ammonia and lactic acid which contributes to fatigue. These waste products are removed by the urea and Krebs cycle. Supplementing with CM is thought to improve the speed at which these cycles remove the waste products consequently delaying the onset of fatigue.
Research supports this theory. Giannesini et al (2009) demonstrated that rats that were supplemented with CM had increased resistance to fatigue. Human testing also has shown promising results. Bendahan et al (2002) supplemented 18 men suffering with fatigue with 6g daily of CM. CM ingestion resulted in a significant reduction in the sensation of fatigue and a 34% increase in the rate of oxidative ATP production during exercise confirming improved aerobic function.
CM does not have an acute effect so should be taken on a daily basis (approx 6g, over several doses) and can be included as part of this stack as a matter of convenience.
Creatine is naturally produced in the human body from amino acids (arginine, methionine and glycine) primarily in the kidney and liver. Creatine plays a number of major roles as a sports supplement. In the liver, creatine is combined with phosphorus to form the compound creatine phosphate (phosphocreatine).
Creatine phosphate is essential for short term energy bursts for such activities like strength training. It is essential for short term energy as it can rapidly convert ADP (adenosine diphosphate) back to ATP (adenosine triphosphate). ATP is the fuel that provides the power for muscular contractions. When muscles are used to lift weights or to perform any kind of activity, ATP is broken down to ADP and energy is released. The amount of ATP stored in the muscle will only fuel a maximum effort such as lifting a weight for 10 to 15 seconds. After that, the muscle must rely on creatine phosphate to restock its supply of ATP. Creatine promotes intense lifting by replenish the necessary energy molecule ATP.
Creatine is probably the most researched sports supplement with the majority of studies focusing on its effects on short-term activity such as weight lifting or sprint performance. Rawson & Volek (2003) review of 22 studies found that the creatine monohydrate group showed an average 8% better gain in maximum strength and a 14% increase in the number of repetitions done with a sub-maximal load in comparison to the placebo group. Kreider (2003) reported that that nearly 70% of creatine studies had reported a benefit to high intensity training. The average gain in strength and repetitions to failure was 5-15%, the increase in sprint performance was 1-5% and work done during repeated sprint performance was 5-15%.
It should also be noted that typically around 10% of people do not respond to creatine monohydrate. The reasons for this are not well understood but it is thought to occur in individuals who already have naturally high levels of creatine (Aagaard 2004). There are many alternative types of creatine available (e.g. creatine ethyl ester, creatine gluconate, etc); however, there is no concrete evidence that these forms are more effective than creatine monohydrate.
Similar to beta-alanine creatine does not have an acute effect. So it is included in this stack as a matter of convenience and should be taken on its own on non training days also.
More creatine information
Previously discussed in the article is the issue relating to caffeine negating the pump enhancing effect of AAKG within the stack. While this is an important issue, its importance should not be over stated. A moderate dose of caffeine (100-200mg) will not entirely counteract the pump enhancing effect of the AAKG so both products can be used simultaneously though obviously not at full efficiency.
Caffeine is a central nervous system (CNS) stimulant. Research demonstrates that it is effective at improving alertness and reducing drowsiness (Zwyghuizen-Doorenbos et al 1990). There is a large body of research demonstrating caffeine as an effect pre-workout supplement in both endurance athletes (Ganio et al 2009, Kreider et al 2010, Cox et al 2002) and in strength training athletes (Beck 2006, Green at al 2007, Hudson et al 2006). Caffeine also has positive effects cognitive and mental focus and performance (Smit & Rogers 2000, Smith et al 1994, Hogervorst et al 1999). Caffeine is a powerful stimulant regardless of your training goals and should be included if possible.
More caffeine facts
Dimethylaminoethanol, known as DMAE, dimethylethanolamine and Deanol, is a central nervous system stimulant that acts as a precursor to the neurotransmitter acetylcholine (Pfiffer et al 1957, Lohr & Acara 1990, Ceder et al 1978).
Studies have shown an increase in vigilance and alertness following administration of DMAE, vitamins and minerals in individuals suffering from borderline emotional disturbance (Dimpfel et al 2003). DMAE has also been extensively used in studies on individuals with attention deficit hyperactivity disorder and Alzheimer’s with positive results showing improvements in attention levels, memory and mental performance in both humans (Fisman et al 1981, Knobel 1974, Ferris et al 1977, Lewis & Young 1975) and animal studies (Levin et al 1995, Blin et al 2009).
For athletes and other active individuals, DMAE may help enhance focus, concentration and mental alertness resulting in improved performance during training thus can be considered a useful addition to any pre-workout stack. Typical dosage would be in the 150-250mg range.
ALCAR is the acetylated derivative of L-carnitine. ALCAR is nootropic and as a precursor of acetylcholine (White & Scates 1990) is thought to enhance brain cognition through its effect upon the acetylcholine system and anecdotal evidence suggests a synergy between tyrosine, DMAE and ALCAR. Its effect on the acetylcholine system is very complicated and beyond the scope of this article and, indeed, beyond the scope of my own cognitive function (I may try an ALCAR/DMAE/tyrosine stack and study the system!). A good review of the system can be viewed here.
Research in animals has shown that ALCAR supplementation increases focus, memory and cognitive performance (Bossoni & Carpi 1986, Freddi et al 2009, Ghirardi et al 1989, Valerio et al 1989). Likewise, research in humans has also been promising: Cipolli & Chiari (1990) demonstrated that ALCAR supplementation improved memory function and constructional thinking in the elderly while Spagoli et al (1991), Passeri et al (1990) and Thal (1996) showed the usefulness of ALCAR in treating Alzheimer’s. Malaguarnera et al (2007) showed supplementation with L-carnitine reduces the severity of physical and mental fatigue and resulted in increased cognitive functions in centenarians. For this stack approximately 500mg should be an effective dose.
The beauty of the nootropics discussed is their versatility: having the potential to increase mental performance, decrease mental and CNS fatigue, improve mental acuity, decrease reaction time amongst a host of other positive benefits. It is easy to see how nootropics may play a positive role in improving and maximising your overall performance whatever your sporting arena. As mentioned before, as the trainer you have the power to decide what works for you. Experimentation is vital and whilst you do all that you can to improve and support your bodies physical performance to increase strength, stamina and endurance, don’t you owe it to yourself to maximise your greatest asset and boost the old grey matter whilst you’re at it? After all, as the old adage goes: what the mind can perceive, the body can achieve!
Is the Osagi Stack any good for cardio?
Absolutely. Given the endurance enhancing and lactic acid buffering effects of the various ingredients of the stack it is suitable for high-intensity interval training (HIIT) and steady state cardio.
Any side effects?
Some people may experience some mild side effects (upset stomach, etc). It is therefore wise to begin using a lower dose of each ingredient to ascertain your tolerance to the stack before increase dosage (obviously only increase if required; many people will find lower amounts work perfectly fine for them making the stack more cost effective).
Do I have to use all the ingredients?
Not at all. The idea of a stack like this is that you can pick and choose according to your goals and budget. The basic stack should be used as a minimum, and supplements like BA, CM, etc are very useful additions.
When do I take the stack?
The stack should be taken approximate 60 minutes prior to training on an empty stomach (empty means no food in the previous 90 minutes).
Can I take the stack along with my protein shake or BCAA acid that I normally have before training?
Ideally no! Other aminos may compete with the ingredients of the stack for absorption so for the stack to be fully effective it should be taken on its own 60 mins before training, on an empty stomach.
If I have an empty stomach for training, won’t my performance be impaired?
Of course it will! It is ok to have a small meal (some protein and carbs) 30 mins after you have consumed the work out stack to give the stack time to get into the blood stream unhindered. The ‘perfect’ protocol would look like this:
- 1 hour before training: Osagi Stack taken on an empty stomach (no food previous 60-90 mins)
- 30 mins before training: small meal of protein and carbs
- Training session
Which ingredients should I take on non-training days?
Creatine should be taken daily. If you’re using citrulline malate or beta alanine as part of the stack they should also be taken daily. Taurine could also be used daily but my preference would be to save it for workout days. DMAE and ALCAR can also be taken daily.
It doesn’t taste too good?
Unfortunately this is unavoidable especially if CEE is part of the stack. Easiest way of taking it is in the least amount of liquid possible (100ml or less) with some lemon or citrus flavour cordial. Remember to stay hydrated before and throughout your workout!
Do I need to cycle this supp?
Cycling is not required. This stack is not stim-heavy so a tolerance will not be built up.
I would like to thank Osagi for some helpful comments and guidance on an earlier version of the article. Furthermore, his previous posts on MuscleTalk act as a hive of information on the Osagi Stack and its various ingredients and were of massive benefit in researching this article.
- Aagaard, P., (2004) ‘Making muscles “stronger”: exercise, nutrition, drugs’ Journal of Musculoskeletal and Neuronal Interactions, 4(2):165-174.
- Andrew, P.J.; Myer, B. (1999). “Enzymatic function of nitric oxide synthases”. Cardiovascular Research 43 (3): 521–531
- Alford C., Cox H., Wescott R., (2000) ‘The effects of Red Bull energy drink on human performance and mood’, Amino Acids 21:139-150
- Avraham Y, Bonne O, Berry EM (1996) “Behavioral and neurochemical alterations caused by diet restriction–the effect of tyrosine administration in mice”; Brain Research, 732(1-2):133-44.
- Beck TW, Housh TJ, Schmidt RJ, Johnson GO, Housh DJ, Coburn JW, Malek MH., (2006), “The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities”, The Journal of Strength & Conditioning Research 20(3):506-10.
- Blin O, Audebert C, Pitel S, Kaladjian A, Casse-Perrot C, Zaim M, Micallef J, Tisne-Versailles J, Sokoloff P, Chopin P, Marien M., (2009), “Effects of dimethylaminoethanol pyroglutamate (DMAE p-Glu) against memory deficits induced by scopolamine: evidence from preclinical and clinical studies” Psychopharmacology, 207(2):201
- Bossoni G, Carpi C., (1986), “Effect of acetyl-L-carnitine on conditioned reflex learning rate and retention in laboratory animals”, Drugs under experimental and clinical research, 12(11):911-6.
- Brøns, C., Spohr, C., Storgaard, H.,Dyerberg, J., Vaag, A., (2004) ‘Effect of taurine treatment on insulin secretion and action, and on serum lipid levels in overweight men with a genetic predisposition for type II diabetes mellitus’ European Journal of Clinical Nutrition, 58;1239–1247.
- Campbell B, Roberts M, Kerksick C, Wilborn C, Marcello B, Taylor L, Nassar E, Leutholtz B, Bowden R, Rasmussen C, Greenwood M, Kreider R. (2006), “Pharmacokinetics, safety, and effects on exercise performance of L-arginine alpha-ketoglutarate in trained adult men” Nutrition 22(9):872-81.
- Ceder G, Dahlberg L, Schuberth J.(1978), “Effects of 2-dimethylaminoethanol (Deanol) on the metabolism of choline in plasma.” Journal of Neurochemistry, 30(6):1293-6.
- Cipolli C, Chiari G., (1990), “Effects of L-acetylcarnitine on mental deterioration in the aged: initial results” Clinical Therapeutics, 132(6 Suppl):479-510.
- Cox GR, Desbrow B, Montgomery PG, Anderson ME, Bruce CR, Macrides TA, Martin DT, Moquin A, Roberts A, Hawley JA, Burke LM., (2002), “Effect of different protocols of caffeine intake on metabolism and endurance performance., Journal of Applied Physiology, 93(3):990-9.
- Deijen JB, Wientjes CJ, Vullinghs HF, Cloin PA, Langefeld JJ. (1999), “Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course”. Brain Research Bulletin;48(2):203-9.
- Dhanakoti, S.N, Brosnan,J.T., Herzberg, G.R., and Brosnan, M.E., (1990), ‘Renal arginine synthesis: studies in vitro and in vivo’, American Journal of Physiology ,259;pp. 437–442.
- Dimpfel W, Wedekind W, Keplinger I., (2003). “Efficacy of dimethylaminoethanol (DMAE) containing vitamin-mineral drug combination on EEG patterns in the presence of different emotional states”. European Journal of Medical Research. 8 (5): 183–91
- Ferris SH, Sathananthan G, Gershon S, Clark C., (1977), “Senile dementia: treatment with deanol.” The Journal of the American Geriatrics Society, 25(6):241-4.
- Fisman M, Mersky H, Helmes E., (1981), “Double-blind trial of 2-dimethylaminoethanol in Alzheimer’s disease” The American Journal of Psychiatry, 138:970-972.
- Freddi R, Duca P, Gritti I, Mariotti M, Vertemati M., (2009), “Behavioral and degeneration changes in the basal forebrain systems of aged rats: A quantitative study in the region of the basal forebrain after levo-acetyl-carnitine treatments assessed by Abercrombie estimation”, Progress in Neuro-Psychopharmacology & Biological Psychiatry, 33(3):419-26
- Ganio MS, Klau JF, Casa DJ, Armstrong LE, Maresh CM., (2009), “Effect of caffeine on sport-specific endurance performance: a systematic review. The Journal of Strength & Conditioning Research, 23(1):315-24.
- Ghirardi O, Milano S, Ramacci MT, Angelucci L., (1989), “Long-term acetyl-L-carnitine preserves spatial learning in the senescent rat”, Drugs under experimental and clinical research, 13(1-2):237-45.
- Giannesini, B., Izquierdo, M., Le Fur, Y., Cozzone, P.J., Verleye, M., and Le Guern, M.E.,(2009) ‘Beneficial effects of citrulline malate on skeletal muscle function in endotoxemic rat’, European Journal of Pharmacology 602, pp. 143–147.
- Gokce, N., (2004). ‘L-Arginine and hypertension’, Journal of Nutrition 134 (10 Supplement): 2807S–2811S.
- Green JM, Wickwire PJ, McLester JR, Gendle S, Hudson G, Pritchett RC, Laurent CM., (2007), “Effects of caffeine on repetitions to failure and ratings of perceived exertion during resistance training.”, International journal of sports physiology and performance, 2(3):250-9.
- Harald, H., Schmidt, H. W., and Walter, U., (1994) ‘NO at work’, Cell, 78 (6), 919-925
- Harris, R.C., Tallon, M.J., Dunnett, M., Boobis, L., Coakley, J., Kim, H.J., Fallowfield, J.L., Hill, C.A., Wise, J.A. (2006) ‘The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in human vastus lateralis’ Amino Acids 30: 279-289
- Hill C.A., Harris R.C., Kim H.J., Harris B.D., Sale C., Boobis L.H., Kim C.K., Wise J.A. (2006), ‘Influence of β-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity’, Amino Acids, 32:225-233
- Hogervorst E, Riedel WJ, Kovacs E, Brouns F, Jolles J., (1999), “Caffeine improves cognitive performance after strenuous physical exercise” International Journal Sports Medicine 20(6):354-61.
- Hudson GM, Green JM, Bishop PA, Richardson MT., (2008), “Effects of caffeine and aspirin on light resistance training performance, perceived exertion, and pain perception” Journal of Strength & Conditioning Research,22(6):1950-7.
- Hull KM, Maher TJ. (1990), “L-Tyrosine potentiates the anorexia induced by mixed-acting sympathomimetic drugs in hyperphagic rats.” Journal of Pharmacology and Experimental Therapeutics. 255:403-409.
- Kendrick I.P., Harris R.C., Kim H.J., Kim C.K., Dang V.H., Lam T.Q., Bui T.T., Smith M., Wise J.A. (2008), ‘The effects of 10 wk of resistance training combined with beta-alanine supplementation on whole body strength, force production, muscular endurance and body composition’ Amino Acids 34: 547–554.
- Kern, B. and Robinson, T., (2009), ‘Effects of beta-alanine supplementation on performance and body composition in collegiate wrestlers and football players’ Journal of the International Society of Sports Nutrition Volume 6, Supplement 1, p 2.
- Knobel M., (1975), “Approach to a combined pharmacologic therapy of childhood hyperkinesis” Behavioral Neuropsychiatry, 6:87-90
- Kovacs, Eva; Stegen JHCH, Brouns F (1998). “Effect of caffeinated drinks on substrate metabolism, caffeine excretion, and performance.”. Journal of Applied Physiology 85: 709–715.
- Kreider RB, Wilborn CD, Taylor L, Campbell B, Almada AL, Collins R, Cooke M, Earnest CP, Greenwood M, Kalman DS, Kerksick CM, Kleiner SM, Leutholtz B, Lopez H, Lowery LM, Mendel R, Smith A, Spano M, Wildman R, Willoughby DS, Ziegenfuss TN, Antonio J., (2010), “ISSN exercise & sport nutrition review: research & recommendations” Journal of the International Society of Sports Nutrition, 2;7:7.
- Kreider, R.B., (2003) ‘Effects of creatine supplementation on performance and training adaptations’, Molecular and Cellular Biochemistry, 244(1-2):89-94.
- Levin ED, Rose JE, Abood L.(1995), “Effects of nicotinic dimethylaminoethyl esters on working memory performance of rats in the radial-arm maze” Pharmacology Biochemistry and Behavior, 51(2-3):369-73
- Lewis JA, Young R.,(1975) “Deanol and methylphenidate in minimal brain dysfunction”, Clinical Pharmacology & Therapeutics, 17(5):534-40.
- Li F., Abatan, O.I., Kim, H., Burnett, D., Larkin, D., Obrosova, I.G., Stevens, M.J., (2006), ‘Taurine reverses neurological and neurovascular deficits in Zucker diabetic fatty rats’. Neurobiology of Disease, 22:669–676
- Lohr J, Acara M., (1990), “Effect of dimethylaminoethanol, an inhibitor of betaine production, on the disposition of choline in the rat kidney” Journal of Pharmacology and Experimental Therapeutics, 252(1):154-8.
- Malaguarnera M, Cammalleri L, Gargante MP, Vacante M, Colonna V, Motta M., (2007), “L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial”, The American Journal of Clinical Nutrition, 86(6):1738-44.
- Passeri M, Cucinotta D, Bonati PA, Iannuccelli M, Parnetti L, Senin U., (1990), “Acetyl-L-carnitine in the treatment of mildly demented elderly patients”, Int J Clin Pharmacol Res 10(1-2):75-9
- Pfeiffer et al (1957), Stimulant Effect of 2-Dimethylaminoethanol—Possible Precursor of Brain Acetylcholine, Science 126(3274), 610-611
- Rawson E.S., and Volek J.S., (2003), ‘Effects of creatine supplementation and resistance training on muscle strength and weightlifting performance’, Journal of Strength & Conditioning Research, 17(4):822-31.
- Reyner L.A., Horne J.A., (2002), ‘Efficacy of a functional energy drink in counteracting driver sleepiness’, Physiology & Behavior, 75:331-335
- Smit, H. J.; Rogers, P. J., (2000), “Effects of low doses of caffeine on cognitive performance, mood and thirst in low and higher caffeine consumers” Psychopharmacology, 152(2), 167-173.
- Smith A, Kendrick A, Maben A, Salmon J., (1994), Effects of breakfast and caffeine on cognitive performance, mood and cardiovascular functioning., Appetite. 22(1):39-55.
- Spagnoli A, Lucca U, Menasce G, Bandera L, Cizza G, Forloni G, Tettamanti M, Frattura L, Tiraboschi P, Comelli
- M, (1991), “Long‐term acetyl‐L‐carnitine treatment in Alzheimer’s disease”, Neurology, 41(11):1726-32.
- Tamura, S., Tomizawa, S., Tsutsumi, S., Suguro, N., Kizu, K., (1966), ‘Metabolism of Glucuronic Acid in fatigue due to physical exercise’, The Japanese Journal of Pharmcology 16, S.138-156.
- Tamura, S., Tsutsumi, S., Ito, H., Nakai, K., Masuda, M., (1968), ‘Effects of glucuronolactone and the other carbohydrates on the biochemical changes produced in the living body of rats by hard exercise’ The Japanese Journal of Pharmcology, 18(1):30-8.
- Thal LJ, Carta A, Clarke WR, Ferris SH, Friedland RP, Petersen RC, Pettegrew JW, Pfeiffer E, Raskind MA, Sano M, Tuszynski MH, Woolson RF., (1996), “A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer’s disease, Neurology. ,47(3):705-11
- Van den Eynde, F., Van Baelen, P.C., Portzky, M., Audenaert, K. (2008) ‘The effects of energy drinks on cognitive performance’. Tijdschr Psychiatr, 50 (5), 273.
- Valerio C, Clementi G, Spadaro F, D’Agata V, Raffaele R, Grassi M, Lauria N, Drago F., (1989), “The effects of acetyl-l-carnitine on experimental models of learning and memory deficits in the old rat” Functional Neurology. 4(4):387-90
- White HL, Scates PW., (1990), “Acetyl-L-carnitine as a precursor of acetylcholine” Neurochemical Research, 15(6):597-601.
- Zwyghuizen-Doorenbos, A.; Roehrs, T. A.; Lipschutz, L.; Timms, V.; Roth, T. (1990). “Effects of caffeine on alertness”. Psychopharmacology 100 (1): 36–39.