Article updated: 2023 Jan 16. doi: 10.101319/ Author Leslie Griver, Robert Henry

Can You Sweat Out THC?

Yes, you can sweat THC out of your system, but the sweated amount is negligible. It can be used to detect marijuana usage, but it is not enough to detox you.

Let’s take a look at what scientists say about that.

How much THC can you sweat out

The study “Excretion of Delta9-tetrahydrocannabinol in sweat” analyzed the excretion of THC in sweat in 11 regular smokers.

They wore sweat patches for 7 days, and then the TCH concentration in patches was measured. The average concentration was 3.85ng/patch.

Another study collected sweat patches from 12 people who were regular smokers. The concentrations were 0.4-2.0 ng/patch.

What does that mean?

That means that the body excretes ~4ng of THC per sweat patch in 1 week. But that’s only 1 patch.

Let’s estimate how much THC will be sweated by the whole body. We’ll assume that each square inch of our skin excretes sweat.

The area of the skin surface of an average man is 3100 square inches.
The area of a single sweat patch is 2.5 sq. inches.

So we need 1240 patches to cover the whole body.

Each patch will get 4ng of THC excreted with sweat per week.

That means 1240*4 / 7 = 708.6 ng of THC excreted with sweat daily.

Let’s compare that with the THC excretion in the urine.

THC is detected in the urine for up to 30 days with a cutoff level of 50ng/ml for regular users.

Let’s assume the minimal values – the average THC concentration in the urine for 14 days will be 50ng/ml.

The average daily urine output is 1.4L per day or 1400 ml.

So the average excretion of THC in the urine will be 70000 ng per day.

Only 35% of THC is excreted in the urine; 65% is excreted in the faeces, which equals 130000ng daily.

The results are:

The amount of THC excreted with the sweat is insignificant, almost 300 times lower than those excreted through urine and faeces.

Of course, we made assumptions and simplifications, but the general idea is correct.

Can sauna speed the elimination of THC?

What if exercise and sauna work to eliminate THC, not because of sweating, but because of increased core or skin temperature?

The sauna can raise your core body temperature by 1 degree Celsius and your skin temperature by 4 degrees Celsius.

These temperature increases elicit several adaptive changes (besides sweating) in your heart rate and blood flow to various organs.

However, a review of the scientific literature found no consistent change in drug elimination.