Rapamycin + Niacin

I’m about to start taking rapamycin. I don’t take any other longevity supplements. I’m also interested in taking niacin as a recent study showed large doses to have great health benefits in a human trial. However I’m aware that rapamycin can cause glucose intolerance and niacin can cause insulin resistance. I’m concerned that using both of them together could therefore create issues. What do people think?

Welcome to the community,
I don’t know about interactions with Rapamycin. But if you haven’t taken a niacin dose before, try it first. For me, the flushing and itching were not tolerable. They might have better preparations available these days.

1 Like

High-dose niacin isn’t necessarily harmless. Even if you reduce flushing risks with coated sustained-release niacin tablets, here are some potential concerns (not comprehensive):

  • Liver injury
  • Hyperglycemia/insulin resistance
  • Hyperuricemia/gout
  • Increased homocysteine
  • Increased risk of infection
  • Other drug interactions

Unfortunately taking enough niacin in therapeutic doses, i.e. to reduce cholesterol etc., might cause liver damage.
As an aside: It kills me that people will diss statins and then take niacin to lower their cholesterol levels, which would probably be the only reason to take niacin with rapamycin.

'Niacin can also cause serious hepatoxicity that ranges from a mild elevation of liver enzymes to acute liver failure."

“Niacin associated hepatotoxicity is generally related to ingestions of around 3 grams per day”
This is about the amount you would have to take to significantly lower your cholesterol.

“The niacin dosage that a doctor may recommend for high cholesterol is as follows: 1500–3000 mg a day orally, divided into two or three dosages. a starting dose of 250 mg at bedtime, gradually increasing by 250 mg a day every 4–7 days up to 2000 mg a day.Oct 30, 2022”


That is a very good point; I first tried Niacin when it was all the rage in the 80s. The dangers were covered in medical school, but I don’t remember everything I was taught except all of the obscene mnemonics we used to study for tests.


I did too, but I couldn’t get past the “flush” which I found not only irritating but seemed to trigger a hyper-allergic bout of contact dermatitis.


Liver problems only come from taking the slow release forms. If you take instant release, the liver gets plenty of time to recover between doses and there is no problem.

Instant release will burn. Start with 50’s and just keep taking them whenever you think of it. Pretty soon you can do 100’s…I don’t know if it’s worth it, but it does work. I have been taking Niacin instant release with Rapa for a couple years. My lipids look better than ever and I think it gives me more NAD which helps.

I have no certainty about statins or the risk of having higher LDL.


OK great thanks. I’m aware of the risks with niacin and agree the instant release minimises liver issues. I also wouldn’t take more than 200mg instant release per day in one dose which I pretty sure is unheard of for causing liver problems. I also know that tolerance to flushing builds up.

My concern was it interacting with rapa and causing insulin issues but you don’t seem to have any problems which is good to hear.

This is the study that got me interested in taking it ahead of other (far more expensive) B3s although the benefits weren’t as clear in healthy adults.


A friend and fellow longevity enthusiast, and PHD in biology out of Stanford University had this to say to me about niacin…

I’ve been a fan of Niacin for quite some time. So many great attributes, not the least of which is lowering cholesterol.

I can’t read the whole article, but I’ll assume that they use straight niacin. That being said, I still think the best bang for the buck is the amide version: Nacinamide (aka nicotinamide). I think this is the version that most readily supports levels of NAD.

Nicotinamide - Wikipedia

And it’s cheap!


Thanks. My concern with NAM is that it may have a negative longevity affect as well. Jury’s still very much out on that though.

It also doesn’t seem to improve various markers (like choloestrol levels) to the same level as NA or in some cases at all.

This was posted on this forum in 2022. If you have not seen/read review;

Review another post from 2022 on this forum

William B. Parsons Jr. MD was involved in the trials in the US using niacin. The information from the person who did the actually work. This is is a consumer book with a plethora of references

This is a great study, and I had read a summary but did not realize that the result was for people with serious problems to begin with. I wish they would have given one of the controls the Niacin as well to see what happens.

I have found it to be very safe, but also hard to put up with the burn. Also the Enduracin is the one my doctor likes (and he is very knowledgeable about it) but he says don’t use it with a hot beverage such as coffee since the part that makes it slow release is like a wax and it will melt and instantly release. Just FYI. I’m sticking with IR.

No they did give it to healthy people too and there was clear benefit. I made the mistake in thinking otherwise when reading it first too. There was only muscle NAD+ benefit in the patients with mitochondrial myopathy but if you read on there were blood NAD+ increases and improvements in other markers with healthy people too. So it was a very positive outcome.

BTW I’m assuming going by your words that you haven’t built up a tolerance to the burn then? I had thought that happened.

Yeah, I take a gram and a half every morning and it does very little now. If I take another gram in the afternoon, then the next day I feel nothing with the morning dose. I forget sometimes and then I get a little burn the next day. So it really works best to keep swallowing the stuff.

Not easy to accomplish this. I read a study where they gave people 3 or 4 grams and talked about the results and when I was building up my tolerance over maybe 4 months I kept saying “where did they get these people that can take 4 grams?”

It helps to take with food, and they say nsaids work too, though I never tried.

1 Like

Been on 500mg of niacin and taking rapamycin since Nov 2021. The niacin dose definitely has an effect on my genetically higher lp(a). The flushing effect subsides faster and is less intense when taken regularly. Non-flushing niacin is ineffective.

Neither NMN nor NR camps (or the much smaller megadosing niacin vitamin camps) have really discussed the NNMT side - it’s almost always omitted completely. The pilot cited only shows treating a deficiency may be beneficial.


I’m not certain about high-dose niacin necessarily being beneficial for “healthy” people to justify it outside of the indicated uses when an important part of NAD+ is consistently omitted - and we know the trials for atherosclerosis have been not particularly compelling at all. There are also possible known harms with high doses.

Literally, no prospective studies demonstrate Lp(a) lowering with niacin in patients with high Lp(a) is beneficial. Subgroup analyses of trials showed that niacin-mediated reductions in Lp(a) were not accompanied by improved clinical outcomes at all. So there isn’t any reason to use it for that AFAIK.

It reminds me of estrogen replacement therapy reducing Lp(a) levels, yet it is actually discouraged for the use of CVD risk reduction because of negative outcomes.

It’s more likely antisense oligonucleotides towards Lp(a) will pan out or PCSK9 inhibitors make much more sense IMO, but we’ll see.

1 Like

One of many I’ve come across.

1 Like