CB4211_Dosage, benefits & legal status
Also known as CB-4211
A modified MOTS-c analog that completed human safety trials and was abandoned over its formulation.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is CB4211?
Plain language first. The technical label stays, but it never stands alone.Overview
It is the only peptide in the MOTS-c family whose human trial has finished and reported. That trial ended in 2021. MOTS-c itself entered a registered phase 2a trial in February 2026. That trial is recruiting and has reported nothing. Liver fat fell by about the same amount on drug and on placebo, injection-site reactions were the only common side effect, and in 2023 the company said the formulation it had used was not suitable for further development.
CB4211 is a chemically modified analog of MOTS-c, the 16-amino-acid mitochondrial-derived peptide, developed by CohBar for fatty liver disease and obesity. The specific modifications were never published, and there is no FDA substance record for it.
What it's used for
Nothing. It was an experimental injection for fatty liver disease and obesity, and development ended. Its value now is as the only finished human-trial record in the MOTS-c family.
How does CB4211 work?
What it does in the body, and where.CB4211 was built from MOTS-c, a short peptide coded by the small separate genome inside mitochondria rather than by the DNA in the cell nucleus. The company described it as a novel and improved analog, so it is a changed molecule and not MOTS-c itself.
- 01The MOTS-c ideaMOTS-c switches on AMPK, the alarm cells raise when fuel runs short. The same switch is pulled by exercise and fasting, so the hope was more fat burning and better insulin sensitivity.
- 02What changed in CB4211The modifications were meant to make the peptide last longer and behave like a drug rather than a signaling fragment. CohBar never published the sequence or the chemistry, so the difference from MOTS-c cannot be measured from outside.
- 03Where it stoppedIn 20 people with fatty liver, liver enzymes fell further than on placebo while the liver fat itself fell the same amount in both arms. The company later said the formulation could not be taken further, and the program was shelved in a merger.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
What the trial measured
Investigational- Human trial88 people took part across three stages: 65 healthy adults on single and then multiple ascending doses, then 23 obese adults with fatty liver randomized to 25 mg daily for four weeks, of whom 20 were analyzed after three dropped out.
- Human trialLiver fat on MRI fell 5.03 percentage points on CB4211 and 4.88 on placebo, from unequal starting points of 21.1% and 15.9%. In relative terms the placebo arm fell further. The share of people whose liver fat dropped by more than 30% was 36% on drug and 33% on placebo.
- Human trialALT fell 21% while rising 4% on placebo, and AST fell 28% against 11%. Both differences were reported at p<0.05 in a 20-person study.
- No dataEveryone in the four-week stage was confined to the clinical unit, so diet and activity were controlled for both arms. That is the usual explanation for a large placebo response in liver-fat trials.
- No dataNo results paper was ever published. Every figure here comes from a company release and a conference poster.
Why it ended
none- Human trialThe only side effect above 10% in the four-week stage was injection-site reactions, listed in the company's own risk factors as something it might not be able to reduce.
- RegulatoryTwo years after the results, the company told shareholders the formulation was not suitable for further development and that attempts to improve it had failed.
- RegulatoryCohBar then merged into what is now TuHURA Biosciences, and the filing says the combined company is not expected to continue developing CohBar's candidates.
CB4211's liver-enzyme results get quoted as evidence that MOTS-c improves fatty liver. Two things are wrong with that. CB4211 is a modified molecule, not MOTS-c, and the liver fat itself moved the same amount on placebo. The ALT and AST figures come from 20 people in a safety study whose primary endpoints were all safety measures. The program's own sponsor then said the formulation could not be developed further, so this is the only finished human record in the MOTS-c family, and it is a stopped program rather than a positive result. A phase 2a trial of MOTS-c itself started recruiting in February 2026 and has reported nothing.
The published record
Papers and trials about CB4211
1 papers tagged human · 0 not reviews or lab · 0 clinical trial publications
1 registered trials · none with posted results
Furthest stage reached: Phase 1, completed, no results posted
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about CB4211
Evidence
Investigational
Category
Longevity and energy
Common vial
Varies
Half-life
Not published
How much, and do you cycle it?
The range, and whether you take breaks.25 mg per day in the phase 1b stage, once daily. Not applicable Discontinued
The only human schedule tested was once daily for 7 days, then 28 days. Development ended in 2023, so there is no cycle to follow.
Not publishedNo figure
The trial measured pharmacokinetics as a secondary endpoint, but no half-life was published in the topline release and no full results paper followed before the program was shelved.
Source: ClinicalTrials.gov NCT03998514 lists pharmacokinetics as a secondary endpoint
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Nothing to store: it is not sold anywhere.
CB4211 has never been marketed, so there is no vial, pen or bottle to keep at home. Supplies for a trial are made, stored and dispensed by the sponsor and the trial pharmacy under conditions set in the protocol. Anything offered for sale under this name did not come from that supply chain.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Not applicable. No product exists and development ended
- Any vial sold under this name: the molecule's structure was never published, so there is nothing to check it against
Stop and get help
- Not applicable outside the closed trial
Common effects
- Transient, mild to moderate injection-site reactions, the only event above 10% in the four-week stage
- No serious adverse events were reported across either stage
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is CB4211 approved?
And where the numbers on this page come from.No. CB4211 was never approved, and its development has ended. There is no legal route to obtain it as a medicine.
- Approval statusInvestigational
- RouteUnder the skin (subcutaneous)
- Checked23 October 2026
- DoseFrom published clinical trials. Not approved by a regulator for this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
What has happened recently
Never approved anywhere, and development has ended. The phase 1a/1b trial (NCT03998514) ran from July 2018 to April 2021 with 88 participants and is recorded as completed. In its August 2023 merger filing CohBar said that "we do not believe that the formulation of CB4211 used in the Phase 1b stage of the trial is suitable for further development" and that "Efforts to develop an improved formulation have not been successful to date." CohBar merged with Morphogenesis and was renamed TuHURA Biosciences; the filing lists CB4211 among legacy assets and says the combined company is not expected to continue developing CohBar's candidates. There is no FDA GSRS record and no INN.
You can compare this against the whole library, or read how to check a seller.
What else is like CB4211?
Others in Longevity and energy, side by side.If you're weighing CB4211, it's worth reading GDF-11, Nicotinamide Riboside (NR), and P110 in the same class.
A modified MOTS-c analog that completed human safety trials and was abandoned over its formulation.
- Dose
- 25 mg per day in the phase 1b stage
- How often
- Once daily
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- Dose
- Research only
- How often
- Not established
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- Dose
- 300 up to 1,000 mg per day
- How often
- Daily
A research peptide that blocks one route to mitochondrial fragmentation, tested only in cells and animals.
- Dose
- No human dose; 1.5 to 3 mg/kg/day by continuous pump in mice
- How often
- Continuous infusion in animals
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- CB4211 phase 1a/1b record, ClinicalTrials.gov NCT03998514(2021)Phase 1, 88 participants, started July 9, 2018, completed April 19, 2021, sponsor CohBar. All six primary outcomes are safety measures, one of them specifically injection-site reactions.
- CohBar phase 1a/1b topline results, August 10, 2021(2021)Phase 1b: 25 mg daily for four weeks in 20 obese people with fatty liver, 11 on drug and 9 on placebo. ALT fell 21% against a 4% rise, AST fell 28% against 11%, glucose fell 6% against 0%, each at p<0.05. Liver fat fell 5.03% against 4.88%.
- CohBar Form S-4 Amendment No. 1, August 10, 2023 (SEC)(2023)States the phase 1b formulation is not suitable for further development and that efforts at an improved formulation have not succeeded. Names CB4211 a legacy asset of the Morphogenesis merger that created TuHURA Biosciences.
Beyond these, 1 records are indexed. Browse the records