A common question that new Kratom users often ask is how long does Kratom last? This article gives a thorough answer to this question based on empirical and subjective data.

Scientifically, how long the effects of a substance lasts depends on the half-life, which is the amount of time it takes for half of the concentration of a substance to be eliminated from the body. Short acting substances have short half-lives, whereas long acting substances have long half-lives.

According to scientific studies, Kratom’s primary alkaloid Mitragynine has a half-life of approximately 3.85 hours. The half-life of Kratom as a whole is a little more complicated, since Kratom contains dozens of other alkaloids which have psychoactive effects. However, using an approximate half-life of 4 hours is a good estimate since most of Kratom’s effects are due to Mitragynine or the conversion of 7-hydroxymitragynine into Mitragynine.

A half life of 4 hours means that if you take 10 grams of Kratom, only 5 grams remains in the body after 4 hours, 2.5 grams after 8 hours, 1.25 grams after 12 hours, 0.625 grams after 16 hours, 0.3125 grams after 20 hours, and 0.155 grams after 24 hours.

This information can be used in combination with the full guide to Kratom powder dosage which was recently posted on Kratom Cafe. 10 grams is a very strong dose, but 4 hours later the half-life causes the effective level of Kratom in the body to decline to 5 grams in terms of effects, which is a medium dose, and then 8 hours later the half-life causes it to decline to 2.5 grams, which is a light dose. 12 hours later the effective level of Kratom in the body declines to 1.25 grams, which is a threshold dose, and after that the effective level drops below the threshold dose, so no effects from the Kratom would be felt after that point.

In simpler words, if you take a really strong dose it will have the most significant effects within 4-8 hours after the dose, threshold effects can be felt up to 12 hours after the dose, and then after that no effects will be felt, although a small bit of Kratom does remain in the body even up to 24 hours after the dose.

I have been using Kratom for a decade, and my subjective experiences, one of which can be read about in this experience report, match up with these scientific findings.

For example, I’ve noticed that effects typically peak in the 1-2 hour range, which matches up exactly with the scientific finding that Mitragynine reaches maximum concentration in the body 1.26 hours after a dose. Then significant effects, such as relaxation, euphoria, and an overall sense of well-being usually last until 4-8 hours after a dose. After that there are no significant effects, but a little bit of relaxation and happiness can be felt perhaps up to the 12 hour mark.

Notably, I only take Kratom once a day, and I find that I have no desire to redose until 24+ hours after a dose, which is around when all of the Kratom is eliminated from the body.

Thus, the best answer for how long Kratom lasts is 4-8 hours, and it is important to mention that effects peak around 1-2 hours after the dose. That being said, some slight effects can linger until about 12 hours after a dose.