There's a few issues at play when it comes to Amphetamine tolerance.
The first one is Catecholamine depletion, which results in the brain being unable to reproduce enough Dopamine, Norepinephrine and Epinephrine neurotransmitters quickly enough to replenish those lost that aren't successfully reuptaken into the pre synaptic storage vesicles. This can be addressed through the use of L-Tyrosine. Word of caution though, L-Tyrosine taken by itself will deplete Serotonin levels and once Serotonin levels have reduced so far, the brains safety mechanism kicks in and it will simply refuse to biosynthesize anymore Catecholamines until Serotonin levels are replenished. This is why it's recommended to take L-Tyrosine and 5-HTP together. A 10:1 ratio seems to be the common recommendation. So for 1000mgs of L-Tyrosine, take 100mgs of 5-HTP each day. This should allow both amino acids to continue synthesizing the neurotransmitters until the storage vesicles are fully replenished.
The second issue and the one that the pharmaceutical industry loves to completely ignore is the downregulation of the Catecholamine and Serotonin receptors. This is caused by over stimulation and results in the receptors being desensitized. It's a lot like jacking off too much and eventually your dick gets more numb to it and it doesn't feel quite as good as it did in the good old teen acne days. There is however some "anecdotal" evidence that suggests that certain "not quite Vitamin B" supplements can help to upregulate these receptors and make them more sensitive again to the neurotransmitter binding process. I personally recommend Myo-Inositol (8 grams per day), but there are others that I have yet to try out. (Sorry, don't know how to re sensitize the dick, that's a whole other topic)
The third issue is in regards to the reuptake channels. When neurotransmitters are released into the synaptic cleft, most of them are reuptaken through their corresponding reuptake channels. This is to allow them to re-enter presynaptic vesicles so that they can be used again when required. Now unlike Methylphenidate or Cocaine which act as full reuptake channel blockers (predominantly Dopamine and Norepinephrine reuptake channels) , Amphetamine only acts as a partial blocker to the Catecholamine reuptake channels. This is because Amphetamine makes it's way through the channels (rather than simply blocking them off) and directly enters the pre-synaptic neurons. However, because Amphetamine enters this way, it slows down Catecholamine neurotransmitter reuptake. Although this effect isn't quite as dramatic as Methylphenidate or Cocaine, the brain may still end up creating more reuptake channels to try and compensate for the partial blockage. Because of these additional reuptake channels, the neurotransmitters can be reuptaken too quickly before they even get a chance to bind to the receptors. Now i'm currently unaware of any supplements or substances that can combat this effect. But it's my understanding that stimulant holiday's will cause the brain to eventually destroy the additional reuptake channels once it realizes there are too many. Again, it's not quite as bad with Amphetamine as it is with Methylphenidate or Cocaine, but the issue may still occur at a slower rate with long term Amphetamine use.
The last issue is the lack of pre-synaptic vesicles themselves. When positively charged Calcium Ions flood into the Axon Terminal through the CA2+ gates (The space between the vesicles within the pre synaptic neurons), they bind to the vesicles and signal to them to merge with the pre-synaptic membrane. When this happens, the neurotransmitters spill out of the vesicles and into the synaptic cleft for some hardcore receptor binding action. Some of these vesicles are then recycled and there are two currently known methods of how some of these vesicles get recycled. The easiest one to understand is the so called "kiss and run" method. This is where a vesicle doesn't fully merge into the pre synaptic membrane and is able to break free after it releases it's neurotransmitters allowing it to float back up into the docking position ready to be replenished with more neurotransmitters. The second method is more complicated and I don't even pretend to really understand it myself. But this is when a vesicle does fully merge with the pre synaptic membrane, but through some complex chemical process, the membrane is able to recycle parts of the vesicles that have fully merged into it and create new ones as a result. Amazingly, this process takes less than 1 minute to occur. However, not all vesicles get recycled and it takes the brain more time to create fresh new vesicles to replace the old ones. The good news is, it's believed to only take 24-48 hours for these new vesicles to take the place of the one's that failed the recycling process. One way you can combat the issue of temporary vesicle depletion is by limiting the amount of Calcium Ions that can flood into the Axon Terminal in a short amount of time. One of the easiest ways to do this is through the use of Chelated Magnesium (Magnesium Glycinate). It acts as CA2+ Gate regulator/partial blocker and because it partially blocks the Calcium Gates it slows down how many Calcium Ions can get into the Axon Terminal and trigger a vesicle to membrane merger. This will of course result in less neurotransmitters getting into the synaptic cleft too quickly which will make the effects of a stimulant seem somewhat less intense. However, the effect will be much more smooth and longer lasting, with no nasty hard crash, you'll get a very smooth roll off instead. 400mgs of Chelated Magnesium is the recommended RDA and no more than that is necessary for general Amphetamine use. Also be sure to stick to a diet rich in Calcium and Potassium as an imbalance of too much Magnesium can be just as bad for your health as not having enough.
So to summarize. Regardless of whether you're taking an Amphetamine break or not. 1000mgs of L-Tyrosine, 100mgs of 5-HTP, 8gs of Myo-Inositol and 400mgs of Chelated Magnesium (Magnesium Glycinate) + a Calcium and Potassium rich diet.
Give these supplements a go each day for several weeks before attempting to use Amphetamine again. But low dose and work your way up and see how your tolerance level compares to how it is right now when you do.
