Tobacco is very good at clearing things from the body, like drugs or caffeine. Smokers clear caffeine faster from the brain than non smokers.
Check out the P450 group of enzymes to find out how this works, part of the clearance rate is controlled by the liver becoming more efficient and altering your food and drink cravings.
Other foods/chemicals like grapefruit juice slow the metabolism of some drugs, so 2litres of grapefruit juice combined with 50Mg of viagra will see you visiting A&E with a 5hr priaprism, that has to be let down with andrenaline injections into the corpus spongiosum.
Generally if you want your illegal drugs to last longer dont smoke.
You can use Mag Oil as another way to get Mg into the body. Its basically Magnesium Sulphate aka Epsom Salts mixed with water and rubbed on the skin. If its really concentrated it will sting the skin, but dilute to reduce the stinging effect. Alternatively soak in a bath with Magnesium Sulphate.
https://www.epsomsaltcouncil.org/wp-content/uploads/2015/10/...
Any sulphate can be absorbed through the skin, so soaking in copper sulphate will get more copper into the body which is useful for all types of Collagen. Copper will also make smokers feel like they are smoking their very first cigarette, ie they will feel nauseous if they smoke within 30mins of taking a copper supplement. I wouldnt advise applying copper sulphate directly onto the skin though as it will debride the skin and is now only used by the US Military for cleaning extreme wounds.
Magnesium irritates the lower bowel hence the diarrhea, so if taken orally, its better to take little and often through the day rather than one big supplement for a day, and always take after eating because tablets breakdown in the gut and get into the blood stream quickly.
Magnesium is also used to make ATP (Adenosine triphosphate) which helps provide cellular energy so being superfit, her demands for Mg will be higher than a sedate person.
Taking Potassium also helps the cells take up glucose, amino acids and other nutrients including magnesium whilst sodium makes the cells take up just water, so in a way sodium starves cells at a cellular level, which could help contribute to a variety of problems including anxiety. To get your daily potassium intake of 4.7grams, you would need to eat 11 large banana's a day. One sign you are deficient in Potassium is you crave sugary foods after eating, but if you supplement around >2g with potassium (chloride/bicarbonate) your sugar cravings will go.