Heroin absorption

Many people die each year from heroin intoxication. Yet the presence of heroin has never been reported in postmortem tissues. How can that be? The main reason is that heroin undergoes rapid metabolic change immediately following administration.

What do drug tests test for?

After heroin is administered it quickly metabolizes into 6-monoacetylmorphine (6MAM). Within 6-25 minutes after that, approximately one-half of the 6MAM will have metabolized into Morphine. Since heroin and 6MAM both have very short half-lives, drug tests do not test for either, but instead test for Morphine.


How long will Morphine stay in your system?

The half-life of Morphine is about 2.5 – 5 hours. Consequently, the half-life of heroin is the combination of both 6MAM and Morphine, or 3 hrs – 5.5 hrs. On the other hand, the drug effects of heroin last between 1 – 2 half-lives, and that means you’ll feel the effects of heroin for approximately 3 – 11 hours, with the average being 7 hours. The drug-effects of heroin are heavily dependent upon the dose, duration of use, and the build-up of heroin tolerance.


Understanding the elimination half-life

The elimination half-life of heroin (diacetylmorphine) is a measurement that represents the period of time it takes the typical human body to metabolize heroin into half the original dosage. In other words, if you shoot 10mg of heroin at 12:30 p.m. and at 12:35 p.m. there is only 5mg of heroin circulating in your system, you would say that heroin has a 5 minute half-life. As we stated earlier, drug tests do not test for heroin but rather for Morphine. The half-life of heroin is really a combination of three half lives; heroin itself (less than 5 minutes), 6MAM (6 – 25 minutes) and Morphine (2.5 – 5 hours).

Elimination half-life schedule

  1. 1/2
  2. 1/2 x 1/2 = 1/4
  3. 1/2 x 1/4 = 1/8
  4. 1/2 x 1/8 = 1/16
  5. 1/2 x 1/16 = 1/32
  6. 1/2 x 1/32 = 1/64
  7. 1/2 x 1/64 = 1/128
  8. 1/2 x 1/128 = 1/256

If you look above you’ll see a bunch of numbers listed 1-8. Number one represents 1 half-life, or 50% (1/2) of the original amount. Number 4 represents 1/16 the original amount or 6.25%. Number 7 represents 7 half-lives. The product of number 7 is 1/128, which means less than 1% (.0078). The number .0078 is derived by dividing 1 by 128. In other words, it takes 7 half-lives to get below 1% of the original amount. It is safe to say that less than 1% means that the drug is effectively gone from your system.


The final product

The half-life of heroin is at most 5.5 hours, i.e. 5 minutes for heroin, plus 25 minutes for 6MAM, plus 5 hours for Morphine. Heroin’s total half-life is 5.5 hours, and when you multiply 5.5 by 7 (for 7 half-lives), your product is 38.5 hours.


Passing a drug test for heroin

To be absolutely safe we recommend you multiply 5.5 hours by 8 half-lives, the product of which is 44 hours. It is safe to say that most people will be able to pass a drug test for heroin after 44 hours has passed since the last dose. The amount of Morphine circulating through your system after 44 hours will be less than 1/2 of 1 percent (.0039 or 0.39%).