I’m inclined to use sirolimus cream on a lot of my skin (face, arms, lower legs), and using it on half of my body makes me worry that it might be absorbed systemically. I would use the stronger version .1% to .2%. I also intend to take rapamycin orally so don’t want to add an unknown quantity on top of that. Does anyone know if topical sirolimus can affect the body systemically?
On another note, what is the frequency people apply it?
I would think the obvious answer is “yes”, but that does not help. The question is how much rapamycin gets around the rest of the body via the skin. I don’t have an answer to this sadly.
In the one major study (ok, not really very major - only n=13) that has been done on this (in which they used Transcutol as the main reagent to dissolve the rapamycin in) there was absolutely no systemic absorption from the topical application of the rapamycin. They could detect no rapamycin in the blood during the study. So, given that study I would say we are likely fine if we follow the same protocol.
Blood was drawn from consenting individuals (n = 13) at the 6-month visit to assess systemic delivery of rapamycin, and tissue from the dorsal surface of both hands was obtained by biopsy at final visit, using a 3-mm punch probe. Biopsies were divided into 2 sections for further analyses (histological evaluation, immunohistochemistry, isolation of total RNA). Rapamycin was measured in whole blood by an independent CLIA-certified laboratory (NMS Laboratories, Horsham, PA).
Of the 17 participants who completed the study, 13 consented to a blood draw and skin biopsy, and 8 tissue samples produced reliable material for further analysis. No blood samples collected contained detectable levels of rapamycin as assessed by LC/MS/MS analysis (limit of detection, 1 ng/ml).
Note - if you use DSMO as the resolving reagent I would say you would get systemic absorption because it is a much more powerful solvent on the skin - so would avoid using DSMO for this application if you are concerned about that.
The original paper is here if you want to read it: Topical rapamycin reduces markers of senescence and aging in human skin: an exploratory, prospective, randomized trial | GeroScience
The full “Rapamycin for aging skin” thread is here: Rapamycin May Slow Skin Aging (Drexel U. Study)
and to make your own rapamycin cream see this thread: DIY Rapamycin skin cream
And to buy it, see here: Where to buy Rapamycin Skin Cream
And I’ve been using it off and on topically for the past 2 years. I typically apply it either every day, or alternating days (using Retin A on the other days - putting the retin A on just before bed).
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Thank you. I hope/assume they probably accounted for the half-life of sirolimus when they took the blood draws. I’ll be taking a test anyway to see how my body absorbs the oral dose.
What percentage do you use? The paper mentions higher doses inhibit cell growth. I plan to take photos of my skin to try to assess whether it’s having an effect, so if a higher dose results in something positive, I may not worry about it.
As a side note I will be buying ready made cream for now. I’m skeptical about a homemade version because I understand making a cream that has a specific absorption qualities is challenging/something requiring chemistry and testing. For example two sunscreens can have the same amount of titanium or zinc, and both could use nano particles, but have wildy different SPFs depending on how the particles are processed and what other ingredients are used. I’m curious if anyone else sees this as a potential problem – any cosmetic chemists here? – I’d still prefer to save the money with a homemade version if I know it’s just as effective.
