If you are already taking Adderall, you might consider a tyrosine supplement (2 or 3 grams a day): amphetamine tends to deplete tyrosine from the dopamine system; and high tyrosine blood levels have been correlated with high dopamine levels. And, as you will see below; high prolactin levels, too (in males). :o
Nutr Neurosci. 2003 Aug;6(4):237-46.
Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on cognitive and motor performance deficits during sleep deprivation.
Magill RA, Waters WF, Bray GA, Volaufova J, Smith SR, Lieberman HR, McNevin N, Ryan DH.
Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
Cognitive and motor performance are critical in many circumstances and are impaired by sleep deprivation. We administered placebo, tyrosine 150 mg/kg, caffeine 300 mg/70 kg, phentermine 37.5 mg and D-amphetamine 20 mg at 15.30 h following overnight sleep deprivation and compare their effects on cognitive and motor performance in healthy young men. Tests of visual scanning, running memory, logical reasoning, mathematical processing, the Stroop task, four-choice serial reaction time, time wall take, pursuit tracking, visual vigilance, Trails (B) task and long-term memory were evaluated at standardized intervals before, during and after sleep deprivation and drugs. Performance decrements with sleep deprivation occurred in visual scanning, running memory, logical reasoning, mathematical processing, the Stroop test, the time wall test, tracking and visual vigilance. Interestingly, with sleep deprivation some tests improved and others did not deteriorate. Improvements with medication following sleep deprivation were seen in running memory, logical reasoning, mathematical processing, tracking and visual vigilance. Although less effective than D-amphetamine, tyrosine improved performance on several tests. We conclude that all drugs tested improved at least some aspects of cognitive and motor performance after sleep deprivation. As a naturally occurring amino acid, and thus amenable to nutritional strategies, tyrosine may deserve further testing.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 12887140 [PubMed - indexed for MEDLINE]
Neuropsychopharmacology. 2004 Feb;29(2):427-32.
Decreasing amphetamine-induced dopamine release by acute phenylalanine/tyrosine depletion: A PET/[11C]raclopride study in healthy men.
Leyton M, Dagher A, Boileau I, Casey K, Baker GB, Diksic M, Gunn R, Young SN, Benkelfat C.
Department of Psychiatry, McGill University, Montreal, Quebec, Canada. marco.leyton@mcgill.ca
Acute phenylalanine/tyrosine depletion (APTD) has been proposed as a new method to decrease catecholamine neurotransmission safely, rapidly, and transiently. Validation studies in animals are encouraging, but direct evidence in human brain is lacking. In the present study, we tested the hypothesis that APTD would reduce stimulated dopamine (DA) release, as assessed by positron emission tomography (PET) and changes in [(11)C]raclopride binding potential (BP), a measure of DA D2/D3 receptor availability. Eight healthy men received two PET scans, both following d-amphetamine, 0.3 mg/kg, p.o., an oral dose known to decrease [(11)C]raclopride BP in ventral striatum. On the morning before each scan, subjects ingested, in counter-balanced order, an amino-acid mixture deficient in the catecholamine precursors, phenylalanine, and tyrosine, or a nutritionally balanced mixture. Brain parametric images were generated by calculating [(11)C]raclopride BP at each voxel. BP values were extracted from the t-map (threshold: t=4.2, equivalent to p<0.05, Bonferroni corrected) and a priori identified regions of interest from each individual's coregistered magnetic resonance images. Both receptor parametric mapping and region of interest analyses indicated that [(11)C]raclopride binding was significantly different on the two test days in the ventral striatum (peak t=6.31; x=-25, y=-8, and z=0.1). In the t-map defined cluster, [(11)C]raclopride BP values were 11.8+/-11.9% higher during the APTD session (p<0.05). The reduction in d-amphetamine-induced DA release exhibited a linear association with the reduction in plasma tyrosine levels (r=-0.82, p<0.05). Together, the results provide the first direct evidence that APTD decreases stimulated DA release in human brain. APTD may be a suitable new tool for human neuropsychopharmacology research.
PMID: 14583741 [PubMed - indexed for MEDLINE]
However, WARNING! High dose tyrosine blood levels have also been correlated with higher prolactin levels. So if you are male,
you might want to not engage in high dose tryosine...
This trials' results contradict the results from above; and both of these trials were randomized (and included many of the same researchers); so it makes you wonder if tyrosine really works as a stimulant by itself....
Nutr Neurosci. 2003 Aug;6(4):221-35.
A comparison of tyrosine against placebo, phentermine, caffeine, and D-amphetamine during sleep deprivation.
Waters WF, Magill RA, Bray GA, Volaufova J, Smith SR, Lieberman HR, Rood J, Hurry M, Anderson T, Ryan DH.
Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
Sleep deprivation can impair alertness and cognitive and motor performance. We hypothesized that the amino acid tyrosine might reduce deleterious effects of sleep deprivation. Seventy-six healthy males, age 18-35 years, participated in a four-day protocol that included a habituation night, a baseline night, a 40.5 h period without sleep, and a recovery night. Tyrosine 150 mg/kg, caffeine 300 mg/70 kg, phentermine 37.5 mg, D-amphetamine 20 mg and placebo were administered in a double-blind, randomized fashion to compare their effects on the time it took to fall asleep, on endocrine responses during sleep deprivation, and on sleep quantity, quality and architecture as measured by polysomnography during recovery sleep. When given after 36 h without sleep, tyrosine had no significant effect on any parameter of sleep. D-amphetamine produced marked decrease in sleep drive but caused deleterious effects on many aspects of recovery sleep. Still, D-amphetamine was associated with increased alertness on the first recovery day. Phentermine and caffeine both decreased sleep drive during sleep deprivation, but phentermine impaired rapid-eye-movement (REM) recovery sleep. Tyrosine (when compared to placebo) had no effect on any sleep related measure, but it did stimulate prolactin release.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 12887139 [PubMed - indexed for MEDLINE]
let's keep looking....
J Psychopharmacol. 1999;13(2):144-7.
Attenuation of some subjective effects of amphetamine following tyrosine depletion.
McTavish SF, McPherson MH, Sharp T, Cowen PJ.
University Department of Psychiatry, Warneford Hospital, Oxford, UK. sarah.mctavish@psyc.ox.ac.uk
Fifteen healthy volunteers received d-amphetamine (20 mg orally) 2 h after ingesting either a nutritionally balanced amino acid mixture or one lacking the catecholamine precursors, tyrosine and phenylalanine (TYR-free). Plasma tyrosine levels were significantly lowered in subjects who received the TYR-free mixture but mean plasma amphetamine levels were higher. Despite this, the TYR-free mixture appeared to decrease the subjective psychostimulant effects of amphetamine, as determined by visual analogue scales. In contrast, the TYR-free mixture failed to lower the subjective anorectic effect of amphetamine. These findings are consistent with animal experimental studies indicating that tyrosine depletion attenuates the release of dopamine produced by amphetamine but not the release of noradrenaline.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 10475719 [PubMed - indexed for MEDLINE]
I might suggest 2 or 3 grams tyrosine a day; on an empty stomach (maybe right after you awaken).
