What blood tests are people taking?, Any rapamycin specific ones?

For full transparency, I work at Marek Health.
We offer low-margin self-service blood testing as part of our mission to reduce the barrier of entry to affordable health care.

Our Rapamycin (Sirolimus) serum blood test (LC/MS-MS) via LabCorp is only $59 vs $95 at LEF.

Additionally, the LEF “Chemistry Panel” (Lipids, CBC, CMP) is only $25 at Marek vs $35 at LEF.

Also, Marek Health offers the high sensitivity CRP test for $20 vs $42 at LEF.
And the IGF-1 test for $39 vs $75 at LEF.

You can find links to the aforementioned tests here: Rapamycin related blood tests - JustPaste.it

If this is against the rules here please delete my post. I stand to gain nothing, I am simply trying to help others get access to the same lab tests at lower costs.


This is helpful information - thanks for posting.

This type of service you are offering seems high value and helpful to our audience.


Hey Mike,

Great questions!

You do not need to pay any consulting fee to access lab tests.
If you want interpretation, coaching, and prescriptions, that is when you would pay a $250 patient exam fee.

Marek Health has two lines of business:

  1. Self-Service Lab Work
  2. Concierge Health Coaching (Guided Optimization)

I’m going to be fully transparent here.
The self-service lab work is not a profit centre for us. It’s goal is to get people access to affordable diagnostic lab work as we believe it’s important. However, it also serves as a free marketing campaign for our brand. We believe if we offer the most affordable, convenient diagnostic lab tests it is inevitable that a huge number of eyes utilize our services. A small percentage of those will read the about marek page, or follow our social media, or read our trustpilot reviews and decide they want help interpreting their lab markers, opimizing their health, improving their longevity, etc and that drives business to our real profit centre – guided optimization.

Hence, the lab test prices you see are not introductory prices or special sales prices. They are simply lab tests with very low margins, mostly to cover overhead.


I noticed Marek offers the new Glutathione test through Labcorp for $59. Other places charge at least twice that. Glynac (NAC + glycine) is reputed to improve glutathione levels. It would be interesting to see if anyone has a measurable increase in glutathione after being on this mix for a while.


Where do you get the lab test for trough serum Rapamycin levels? I’d like to test mine.

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I think most people are using LEF or Marek Health. The latter costs less. Here is a link.

Both of these companies use Labcorp. You can find out if there’s a nearby lab at this link.

In some areas you may only have Quest Diagnostics. In that case, you could use Ulta Labs. It’s more expensive: Sirolimus, LC/MS/MS | Ulta Lab Tests

You can look for nearby Quest Diagnostics locations here.

When you order labs yourself, they’re pre-paid and not through insurance. NY, NJ, and RI restrict self testing.


You can read up about them here How to get a Rapamycin (sirolimus) Blood Level Test

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Thank you, much appreciated!

Why am I not surprised you had a long post on this? Thanks!

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Wondering who is your doctor?

I do not understand why your RDW would be a bio marker of any value and would help lower your bio age by 13 years. It is the Red Cell Distribution Width, affected chiefly or solely by your iron stores. Little use beyond that clinically. But Your obviously well read and invested in the process (I am 63 as well) so curious of your thoughts.

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I disagree, RDW is used as an epigenetic age marker on many age calculators because there are many, many papers citing RDW as a risk factor.
The paper below is just one example.

“RDW levels above the median were associated with a significantly lower survival rate on long-term follow-up”

“Higher RDW levels at discharge were associated with a worse long-term outcome, regardless of haemoglobin levels and anaemia status.”


So with machine learning algorithms we are likely to see a host of associations. RDW as a Biomarker could be related to iron deficiency from an early GI malignancy before anemia develops. There are confounding variables not related to aging. The question is, does lower RDW mean better health? We have seen many bio markers like homocysteine not really pan out or deliver. In Geroprotective markers, the controversies are even more complicated.

My comment was more that if his bioage dropped by 13 years in four months, hard to fathom. Especially hard to fathom if it was based on an obscure marker like RDW and a more solid one like creatine. But again, we don’t know how much of a change or why it flipped the formula so much. A creatine of 0.9 changing a little means nothing, especially if working out and good muscle mass. I am sure his creating did not go down from 2.4 to 1.1, something clinically that would give him 13 more years.

But I will read more into the RDW articles, thanks for the link.

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I agree. I don’t place much stock in the epigenetic age tests, but maybe they tell me if I am going in the right direction.

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comprehensive biological, fluid physics and optics studies showed that variation of red blood cells size measured by RDW results in increased interactions between vascular wall and circulating morphotic elements which contribute to vascular pathology.


I think (but didn’t search long enough to find the references) that blood stem cells tend to not work as well with advancing age & that one symptom is an increase in RDW.


Shouldn’t there be a guideline for a specific blood concentration of sirolimus to be below at trough? Rather than this weird heuristic of 5 half-lives? I mean why would the level you need to get down to be higher if you took a higher dose? I don’t understand the logic there.

Does anyone have a best guess as to what blood level the trough should be below to be safe?

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Its actually rather funny… during the past 20 years of rapamycin / sirolimus use, the entire goal was the opposite (how to keep the blood/sirolimus levels above a certain level … I think above 5ng/mL (or in the range of 5 to 15 ng/mL), for transplant patients so that the donor organs don’t get rejected.

Now that we’re using it for longevity, our goal is the opposite (sort of), to make sure trough levels get down to some nominal value, to minimize side effects and mTORC2 inhibition. So - you are right - we don’t have any hard and fast rules for what that lower target is. We need to develop it. Dr. Green just gives a rough rule of thumb to help make it simple for people, which may be enough.


The reason for using 5 half-lives is because after 5 half-lives the through level will have reached steady state levels. If the trough level after 5 half-lives is very low, you know the drug is not accumulating significantly with repeated doses. Taking a rapamycin trough level blood test to find how long you have to wait to get a very low concentration would also be useful, but rapamycin blood tests aren’t so accurate at very low concentrations. One lab I know of only gives a level of <1 if it’s low, which doesn’t tell you whether you have 0.5 or 0.7 or what.

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But that begs the question: what is the level that qualifies as “very low”?
And since a typical Half-Life time for wrapamycin metabolism is just a bit under 3 days, only those taking it about once every 2 weeks will have five have lives to work with.

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The thing is, no one actually knows the half-life in any one individual.

"The half-life of rapamycin is about 3 days, or 58–63 hours. In a study of long-term, low-dose oral rapamycin, the mean half-life was 38.7 hours