Taking rapamycin on a 3 day water fast

Does anyone have any experience taking rapamycin in the middle of a 3 day fast?
I am trying to decide if it would be helpful, or if I should just skip this week.

Many people are doing this to increase autophagy. I think I will try it soon. I saw this on another forum, regarding fasting and rapamycin:

I do a three day fast once a month. I have been doing it for ages but only recently added Rapa. Two things, adding Rapa does make it easier. But also it just gets easier the more you do it. You get more metabolically flexible so its easier for your body to swap fuel sources without needing to slow down metabolism to conserve energy. Well that’s what I think anyway. Good on you for giving it a whirl! I remember David Sinclair said fasting and/or very low calorie diets (which have basically the same effect) are the longevity techniques with the most solid evidence behind them.


I am doing a 5 day fast, once every 3 weeks. I do a longer fast about once every 3 months. I take rapamycin on the first day. I took 10mg this time.


I did a 5 day water fast, and am currently doing a 5 day partial fast. I took 12 mg of rapamycin with a grapefruit salad on the night before the fast. I got my first rapamycin induced mucosal ulcer. It is no big deal. It is very different than fever blisters I have had, because there is no puss. I look forward to eating normally next Monday.


Question for the three to five day water fast? I have done two day water fasts only and lately finding it harder to fight the hunger. Any tips to fight the hunger?

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I drink a lot of bone broth during my fasts - and tea, and those both help me. Not a pure 'water fast" but close enough for me. The most I’ve done so far is a 3 day fast, and day 2 is fine, but I start to feel weak by day 3, and hard to get work done.

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the key is to supplement properly when fasting

i take slow mag for magnesium 4-6 pills
and zero calorie bone broth for sodium (2-3 grams per day)
i also drink black coffee when needed

the hard parts for me are:
I feel cold as thyroid function drops
I am a sensitive sleeper, and its more difficult during a fast

I will take my rapa tomorrow morning (day 2), and then go to the gym


Thanks for the reply. Any recommendation for bone broth to buy? I find day 3 very hard a well…hard to focus and concentrate…and I’m a professor…and hard to teach on day 3.

My reply to Zmm for for both Rapadmin and Zmm.

This is what I use
It’s basically 1gram of sodium per packet

And then slow mag

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These two links cover the why, and also how much


As far as hunger overall
Sodium and magnesium definitely help

The higher your ketones go, the less hungry you will be. You should still have your full strength, but probably less energy stamina

I have found that there are things that can be done to make the fuel transition to ketones easier and faster

Eat keto the day or two before starting to fast

Lift weights on the first day of the fast to deplete glycogen faster

I use the keto mojo to check glucose and ketones periodically when fasting

Generally, the lower the glucose, the higher the ketones

I find that by day three usually, glucose is flat at around 60 (unless I just did exercise or sauna), and ketones can be 4-6 which is high

Once ketones hit this number, hunger is almost not existent. However within minutes of starting to eat, I get hungry again

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When I take rapamycin for a fast, I want to make sure its effects are largely gone by the end of the fast. Post-fasting, many tissues that have been reduced/recycled by the fast are primed for regrowth, which means mTor is needed. This is a major benefit of fasting, so don’t short-circuit it with mTor inhibition.

For a 5 day fast, I’ll take my weekly rapa dose 2-3 days before the fast, then delay the next dose until 3 days after the fast ends.


Given how hard I’ve needed to work to gain some muscle, I’ve personally been avoiding extended fasts, out of concern for losing lean body mass. I do however practice time restricted feeding on a daily basis (typically 16/8 or 18/6).

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ZMM, thanks for the very helpful information.

My local Costco has a few different versions that are a good value. I buy the Pacific Foods Organic bone broth. It tastes good.

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I just took 6mg of rapamune (morning of day 2).
I usually take 7mg, but figured on a fast to try a bit less.

I checked my ketones right before, and plan on checking them again after 60min. I am curious if rapa will boost my ketone (fat) utilization, similar to additional fasting.

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Day 3 and feeling great. Rapa definitely did not make fasting harder, and may have made it easier.

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Ended up being my best fast so far
I have no idea if it was because of the rapa, or in spite of it

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@brandy, for some reason min protein requirements aren’t widely known, and the need increases with age especially >60yo to prevent sarcopenia. >100 grams protein, a small variance male/female but most I suspect aren’t getting enough quality protein especially if ones diet includes too much carb or vegetables. My ability to eat volume has dropped forcing me /us to move to nearly 100% carnivore + protein shakes in the AM + map-aminos (non fast breaking)) first thing AM.

I’ve not read here re muscle loss on rapa. I’ve seen my weight drop and I bet muscle drop too even though I work hard (house remodeling) and eat nearly my needed protein / day…

Something for you to look into, getting enough protein. IE in a paleo diet where you under consume protein the body will burn the protein instead of making/repairing/building mucle… As well as burn muscle mass. :frowning:

I am yet to take rapa (tomorrow, baby step, 2mg).

But in my experience, fasting gets easier after 3 days. Like a steady state. You get sharper, more energy, heightened senses, better mood, etc.

By day 5+, you kind of regret having to eat again and losing your ĂĽber self (and I am very gourmand).

But you DO need to suplemment with mineral salts. Or you will feel weak and prone to fainting. Some small spoons of “fleur du seul” are enough for me.


Saw this today - we still don’t know why rapamycin tends to cause apthous ulcers (mouth sores) in people - interesting to see it triggered (or seems to be triggered… perhaps it was just coincidence) by rapamycin plus fasting:

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