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Fatigue during third week of MOTS-c and whether to keep going

28 replies13 peopleJul 9, 2026☆ Follow
Summary

Why does MOTS-c cause exhaustion around week three and should the cycle be stopped or continued

The original poster reports strong fatigue starting in week three on 3.3 mg three times weekly after two decent weeks. Several replies link the tiredness to low carbohydrate intake interfering with the peptide's AMPK effects and possible calorie deficit. Suggestions include raising carbs slightly while staying on the cycle or pausing peptides altogether if side effects appear. Later posts discuss SS-31 pairing, dosing variations, and age-related mitochondrial considerations without reaching one clear protocol.

What this discussion establishesWhere people disagree

Whether to push through the fatigue or stop immediately, and whether low-carb users should add carbohydrates or abandon MOTS-c

Still open

Optimal length of cycle, exact dosing schedule, and necessity of SS-31 pre-treatment for most users

Nothing here is advice.

28 replies · 13 people
ClearQuill84archiveopening postJul 9

I asked about this in another thread but got no reply so I started a new one. I am now in week three of MOTS-c at 3.3 mg three times a week. The first two weeks felt okay with maybe a bit more energy that could have been placebo. Week three has been rough though with constant exhaustion, sleepiness all day, and trouble getting through workouts or even small tasks. I am 49, have followed a clean high-protein diet without alcohol or junk for about five years, but earlier habits may have left my mitochondria less than ideal. I did not run SS-31 first. I have read that this kind of dip is common around weeks two or three while the body shifts its energy systems and that things should improve later. I am unsure whether to push through the full cycle or stop now.

ClearKettle55archiveJul 9
↳ replying to @ClearQuill84 (opening post)

I never recommend pushing through negative effects with these compounds. I have had few problems myself but even CJC that I liked started causing issues so I plan to drop it. Are you taking the MOTS-c fasted and training fasted as well? Many people report better results that way. The idea is that AMPK activation tells the body to draw energy from fat stores, glucose, and other sources which can support a fasted session aimed at fat loss.

ClearQuill84archiveJul 9
↳ replying to @ClearKettle55

I already follow intermittent fasting with two meals a day, the first around noon and the second after my evening workout. That means the dose at 7 am is taken fasted and the workout is also fasted. I have been low-carb for four years and did a full year of keto so my system is used to pulling energy from fat rather than glucose.

GreyAlder39archiveJul 9

MOTS-c works through the AMPK pathway but much of how it functions is still unknown since it was only discovered about ten years ago. One thing worth checking is blood sugar because early cycles for me produced nighttime lows lasting roughly an hour and the current cycle keeps readings about 20 mg/dl lower than retatrutide alone. That drop can easily explain the fatigue. If daily carbs stay under 25-50 g and you are in ketosis the combination may not work well. SS-31 can be used at the same time but most alternating schedules have little scientific support and are mainly due to cost. For me the effect has been mixed with some days feeling like a sudden oxygen boost.

ClearQuill84archiveJul 9
↳ replying to @GreyAlder39

That could be exactly what is happening because I have kept carbs low for years and rarely go above 50 g a day.

GreyAlder39archiveJul 9
↳ replying to @ClearQuill84

Then that is probably the cause. I have stayed between 10 and 25 g daily for six years yet still deal with stubborn blood-sugar problems and cannot reach ketosis. You might get better results from SS-31 instead.

ClearQuill84archiveJul 9
↳ replying to @GreyAlder39

So what do you recommend doing now? Should I raise carbs, keep going with MOTS-c for the full six weeks, and monitor how I feel?

GreyAlder39archiveJul 9
↳ replying to @ClearQuill84

If the low-carb approach has worked well for years I would stay with it. MOTS-c can help when insulin resistance shows up or as a partial stand-in for metformin, but older studies found that lowering calories to around 400 kcal with a low-carb diet produced similar improvements in insulin resistance and glucose control. The peptide itself is fairly stable so storing it for a couple of years should not be an issue.

NorthWillow72archiveJul 9
↳ replying to @GreyAlder39

Could the tiredness simply come from running too large a calorie deficit? On my first cycle I was at 1200 kcal daily and often felt drained. The second cycle came after reaching goal weight and raising calories and that time the energy benefits appeared. There is research on how GLP-1 medications interact with fatigue and calorie restriction.

GreyAlder39archiveJul 9
↳ replying to @NorthWillow72

A calorie deficit certainly does not help but after years at the same intake most people reach equilibrium so the fatigue here seems tied more directly to MOTS-c. Thanks for the reference. Retatrutide has cut my appetite sharply and some days it is hard to hit even 50-60 g of protein. Sodium drops and low blood pressure episodes have increased especially in the heat so electrolytes and a multivitamin have become necessary, yet the overall benefits still make it worthwhile.

SharpKettle23archiveJul 9

Thanks for the thread. I am already on retatrutide and plan to begin SS-31 and MOTS-c soon.

BlueMarble90archiveJul 9

What dosing schedule are people following for SS-31? I have seen 5 to 10 mg daily mentioned but that adds up quickly. How can someone tell whether it is actually needed or worth the cost? I have been using MOTS-c fasted before workouts and have noticed an energy increase.

LevelCinder55archiveJul 9

I am in week two of MOTS-c at 2 mg five days a week. I am not sure I feel much overall except that cardio sessions feel easier. I used to sprint one minute then cruise for ten and now I can sprint two minutes and still finish feeling good instead of wiped out. It might just be normal progress but the change happened after starting the peptide.

NorthWillow72archiveJul 9
↳ replying to @BlueMarble90

Age matters because mitochondrial damage accumulates over time. In my late fifties I felt confident the compounds would help.

CopperAlder51archiveJul 9
↳ replying to @BlueMarble90

One mitochondrial protocol calls for 4 mg of SS-31 daily for six weeks. I ran SS-31 and MOTS-c one after the other. Newer ideas suggest combining them but those come from rat data. If someone is already running low on metabolic resources the peptides can make fatigue worse because they increase mitochondrial output that still has to come from somewhere. Keeping protein and carbohydrate intake adequate seems necessary to get results from the approach.

GreyAlder39archiveJul 9
↳ replying to @BlueMarble90

Whether it is useful depends on age and current health. Under roughly 50 with no heart, liver, or metabolic issues most people will not notice much benefit.

WarmSparrow33archiveJul 9

I am currently running SS-31, MOTS-c, 5-amino, and NAD together. So far I have not seen much change but I intend to keep going. I did take a full two-week break on a doctor's advice before restarting.

BlueMarble90archiveJul 10
↳ replying to @CopperAlder51

Thanks, that protocol is helpful. I already take 5-amino and NAD so that part is covered. I will pick up some SS-31 and try the six-week plan. For context I turn 62 this month, am generally healthy, and have been losing weight after gaining about 50 lb over thirty years. I have dropped 26 lb so far and am approaching 20 percent body fat, so I thought a mitochondrial reset might be useful.

CopperAlder51archiveJul 10
↳ replying to @BlueMarble90

One note from my experience: 5 mg of MOTS-c felt like too much, almost like rocket fuel, so I settled on 4 mg as the right amount. It also helps to start lower the first week to see how you respond because allergic reactions have been reported. I used 1 mg, then 2 mg, then 3 mg on Monday-Wednesday-Friday during that first week.

GreyPebble34archiveJul 12
↳ replying to @LevelCinder55

I am about to begin MOTS-c and was wondering about dosing. Some people use 2 mg five days a week while others do 10 mg split across three days such as Monday-Wednesday-Friday. Does the schedule itself matter?

IronLedger90archiveJul 12
↳ replying to @NorthWillow72

I agree with that stack. Mine is almost identical except I use 3 mg of SS-31 every day. At 44 I have not had any fatigue or other side effects and I have noticed steadier energy during the day. Normally I feel drained right after work but lately that has improved.

GreyPebble34archiveJul 12
↳ replying to @BlueMarble90

What dosing schedule did you follow for MOTS-c? I am about to start it along with 2 mg of retatrutide.

IronHarbour22archiveJul 13
↳ replying to @GreyPebble34

The protocols I see online for MOTS-c and NAD+ vary widely. I chose a fairly conservative plan: 5 mg of MOTS-c every five days for a few weeks and a loading week of 50 mg NAD+ daily followed by 50 mg two or three times a week. Most suggestions are higher but I prefer to run my own smaller experiments.

LevelCinder55archiveJul 14
↳ replying to @GreyPebble34

I am not an expert on dosing. Some sources suggest very high amounts like 40 mg a week which gets expensive fast. Others I have spoken with say 2 mg per injection worked for them with modest but noticeable effects. I may increase the dose or stop depending on how things go. I do not understand how the studies used 40 mg three or four times a week because that would empty an entire vial in one go.

CopperAlder51archiveJul 14
↳ replying to @LevelCinder55

I have not heard of anyone injecting 40 mg of MOTS-c in a single day. That amount would be extreme and probably too much for me. My personal limit is 4-5 mg and I followed the protocol at 4 mg three days a week. I have heard of that kind of dosing with SS-31 though, which is a different compound.

SlowLantern50archiveJul 14

I have started my first week of MOTS-c at 10 units three times a week and have not noticed anything yet. I will see how the next week goes.

LevelCinder55archiveJul 14
↳ replying to @CopperAlder51

I have seen study references to those high amounts but I do not know anyone who could afford them. Even 40 mg a week would be a stretch for me. The protocol you mentioned earlier already sounds intense. I showed it to my training partner and he was interested but wanted me to try it first because I could handle the cost better. Being a test subject is one thing but that schedule feels like too much.

CopperAlder51archiveJul 14
↳ replying to @LevelCinder55

I completed the full 14-week protocol and others have as well. SS-31 is daily while MOTS-c is three times a week so total MOTS-c comes to 15 mg weekly. I am not sure where the 40 mg figure came from because that protocol does not reach it. I have not heard of anyone using that much MOTS-c and it could be risky.

SlowLantern50archiveJul 15

I am now entering the second week of MOTS-c and still have not noticed any changes.

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