Topical half life

Can anyone comment on topical application? It looks like oral half life is *58–63hrs.

Assuming topical is similar does it make sense to use daily or every other day?

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The topical rapamycin doesn’t get into the blood stream so half life isn’t a relevant point of discussion. There has been only a single skin cream rapamycin study… See here Rapamycin May Slow Skin Aging (Drexel U. Study)

They used daily I believe, and that is what I do. If I get a pimple I pause for a few days.

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Can you explain how its not relevant? The compound is presumably active for a specific amount of time.

If you don’t have an answer thats, okay its not clear why you want to declare it irrelevant. That seemed pretty confident, can we assume you’re a biologist or have expertise in this field?

When we talk about “half-life” of a drug like rapamycin we are typically talking about its blood/plasma half-life. As wikipedia says " In a medical context, the half-life may also describe the time that it takes for the concentration of a substance in blood plasma to reach one-half of its steady-state value (the “plasma half-life”)."

When we put rapamycin (in a topical mixture) on our skin I don’t think there is anything equivalent to the types of processes we have inside our body that will steadily decrease the amount of rapamycin on our skin. It may be something that happens, but I’ve not seen any references to this in any of the literature, and in the one topical rapamycin on aging skin study, they did not find any absorption of the rapamycin into the blood stream. I’m not a biologist, but I’ve read hundreds of rapamycin research papers over the past few years.

Anyway, in the one topical rapamycin skin study that was done they applied every day or two and saw some reasonable positive results. I’ve been doing the same for a significant portion of the past few years (perhaps 30% to 40% of the time, sometimes using DIY rapamycin cream, sometimes getting it from GetHealthspan) and I have also seen a moderate positive effect.


If you’re looking at topical use for skin improvement and regeneration, I’ve been using 0.2% siriolimus/rapamycin, for almost 3 years. This as a skin solution has improved my neck skin and facial skin.

However, if we’re talking about topical solution for hair. I put it also in a solution with minoxidil and get a good growth of hair. Past two years.

There is no consideration of a 1/2 life because you wash it off your face… neck within a day, or wash your hair daily or every other day.

Good point. I actually typically wash my face every morning when I get up, and evening before bed - so yes, any topical cream is going to be mostly eliminated during those washes.

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