MOTS-c vs ATX-304 (My n=1)
To start, these compounds are similar, yet very different. Both are marketed as exercise mimetics and activate AMPK. MOTS-c is a peptide your mitochondria already make, while ATX-304 is a research chem heading into Phase 2. I have experimented with both, so I will dive into the science and my n=1 for both below.
(All of this information is for educational/research purposes only, not medical advice, just my n=1 experience)
Origins:
MOTS-c:
- Discovered in 2015 in Pinchas Cohen's lab at USC, so it's a relatively new discovery
- 16 amino acid peptide encoded in your mitochondrial DNA (12S rRNA region), not your nuclear DNA
ATX-304:
- Started life as O304 at Betagenon, a small Swedish biotech out of Umeå
- Cambrian Bio launched Amplifier Therapeutics in 2023, which bought Betagenon
- Oral small molecule, NOT a peptide
Mechanisms of action:
AMPK is the fuel gauge in your cells. When energy runs low (training, fasting) it flips on and tells the cell to pull in glucose, burn fat, and build more mitochondria. It also tells the cell to quit spending energy on building stuff, which comes up again later and is relevant to the mTOR discussion, as these two pathways seem to see-saw a bit.
MOTS-c MOA:
- Gets to AMPK the long way around
- Jams the folate cycle, AICAR builds up, AICAR flips AMPK
- Under metabolic stress it moves into the nucleus and turns on antioxidant response genes
ATX-304 MOA:
- Goes straight at AMPK
- Keeps it locked on by blocking the step that switches it back off (dephosphorylation at Thr172)
- Your cells don't have to run low on energy for it to work. ATP held steady at every concentration Cambrian tested
- The Umeå group later showed it also acts as a mitochondrial uncoupler, burning extra fuel to create demand
The research:
MOTS-c
Mice:
- ↑ Running capacity and physical performance (young, middle-aged, and old)
- ↓ Insulin resistance
- ↓ Diet-induced weight gain
- ↑ Healthspan, even when started late in life
Humans:
- ↑ Muscle MOTS-c ~12x after a workout
- ↑ Blood MOTS-c 1.6x during exercise
- ↓ Levels with age
- No trials of injected MOTS-c yet
ATX-304
Mice:
- ↑ Muscle glucose uptake
- ↓ Body weight and body fat, even while eating more
- ↓ Insulin resistance
- ↑ Fat used as fuel
- ↑ Heart function and exercise capacity in aged mice
Humans:
- ↓ Fasting glucose
- ↓ Insulin resistance
- ↑ Blood flow to small vessels
- ↓ Blood pressure
- ↓ Liver fat
- ↓ Visceral fat
- ↓ Triglycerides
- ↑ Adiponectin
- ↑ Resting metabolic rate (8%)
- Minimal weight loss at 400mg (Phase 2 plans higher doses)
My n=1 observations:
MOTS-c:
- Felt the energy within the first 2 days, and it stayed consistent the whole run
- Higher work capacity ceiling in the gym
- Low level focus boost
- Jump in caffeine sensitivity
- Fat loss felt faster stacked with GLP1
- A1c improved a ton (can't split this one from GLP1), insulin sensitivity is the best it's ever been
- Clean for the first 3-4 months, then a mast cell reaction basically overnight
- Coming off: not much, maybe a slight dip in energy
ATX-304:
- Slight energy boost at lower doses
- Effect builds the longer I run it (O304 has a long half-life, and it took 14 days to reach steady state in the 2018 trial)
- Body temp seemed to increase at higher doses, but I do not have measurable data on this
- I believe I have experienced some slight fatigue as the uncoupling effect kicks in, but the experiment is heavily confounded
- 188 to 181 lbs in the first week back from vacation, after bumping to 100mg+ stacked with SLU-PP-915 pre cardio (a chunk of that is likely post-vacation water)
- Eating more carbs than usual without gaining weight
- Increased bowel movements, up to 7x a day when I started
MOTS-c: 2mg daily AM, subQ (months, goal: energy and accelerated fat loss)
ATX-304: 50mg titrated up to 150mg, oral (ongoing, goal: speed up fat loss)
RHR, sleep scores, and labs stayed pretty consistent across both runs. Not much changed. hs-CRP stayed at 0.5 mg/L.
The mast cell reaction (MOTS-c):
First 3-4 months on MOTS-c were completely fine, no issues. Then basically overnight I couldn't tolerate it. Every pin left a welt that stuck around 7+ days.
The explanation that makes the most sense for this is that mast cells sit in your skin loaded with histamine. With repeat pinning, your immune system can quietly build IgE antibodies against the peptide. Those antibodies park on your mast cells and nothing happens for a while. Once you're sensitized, the next pin cross-links them and the mast cells dump histamine. So it can go from zero to welts overnight after months of nothing.
Classic hives fade within a day. Welts that last a week likely mean a slower, delayed-type immune reaction on top of the histamine.
Re-exposure after sensitization can escalate to full body hives, lip/tongue/throat swelling, trouble breathing, dizziness, anaphylaxis. I was lucky and never got past the welts, but I have heard anecdotal reports of people who have had much more extreme reactions.
FDA flagged immunogenicity from peptide aggregates and impurities as a risk for MOTS-c in its compounding review.
Confounders:
- GLP1 running in the background for both
- MOTS-c ran alongside SS-31 and a few other peptides
- My body started rejecting SS-31 too, which is what pushed me to switch to SLU-PP-915 + ATX-304
- ATX-304 runs alongside SLU-PP-915 (10mg), which pushes the same oxidative side through ERR
Things to be mindful of:
- Adverse reactions on MOTS-c are more common than people think
- ATX-304's human data is two small, short trials, and the newest isn't peer reviewed
- ATX-304's GI response is real, especially early and on an empty stomach
- FDA's own reviewers recommended against listing MOTS-c. The PCAC committee voted 7-5 in favor. Nothing changes until FDA does rulemaking on the compounding side
- Running both at once is in some ways double-dipping the same switch
My take:
I'm staying on ATX-304 until my growth phase starts.
AMPK and mTOR pull in opposite directions, so once the goal is building muscle, I want to promote an environment in my body that's as conducive to doing so as possible.
MOTS-c did its job for months. The energy was real and stacked well with a GLP1. If it wasn't for the adverse reactions, I would likely still be on it.