Comment by majkinetor

Looking further into it, it seems that we simply don't know much about it, but as I pointed out earlier there is measurable waste disposal. You can imagine that precise knowledge is difficult to measure as it probably must be done separately by each waste product.

This review from 2019 states:

> However, the effectiveness of sweat glands as an excretory organ for homeostatic purposes is currently unclear as there are no comprehensive reviews on this topic.

https://www.tandfonline.com/doi/full/10.1080/23328940.2019.1...

It also mentions stuff similar to the things you wrote:

> The role of sweating to eliminate waste products and toxicants seems to be minor compared with other avenues of excretion via the kidneys and gastrointestinal tract; as eccrine glands do not adapt to increase excretion rates either via concentrating sweat or increasing overall sweating rate. Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body may be an artifact of methodological issues rather than evidence for selective transport.

However, the problem here is that normal sweating is taken into account, but discussion here is about sauna/exercise in which case sweating waste products approach kidney flux rates (which is why people do those things to detoxify) - human can easily sweat 1.5L per hour in that case, which is comparable to daily pee volume, and there are measurements regarding sweat composition that show comparable waste excretion:

    | Substance | Sweat (1h) | Urine (24h) |
    | --------- | ---------- | ----------- |
    | Urea      | ~0.3–1.2 g | ~20–30 g    |
    | Lead      | ~5–50 µg   | ~10–50 µg   |
    | Arsenic   | ~10–60 µg  | ~20–200 µg  |

So, I wouldn't dismiss based on current knowledge, and besides, this has no practical importance even if so, as sauna has the number of other measurable benefits.

Otherwise, I agree with you regarding focus - liver should be treated as sanctuary.