MOTS-c in Kidney Disease: Biomarker Studies Do Not Set a Dose

The Missing Study Is Pharmacokinetic, Not Arithmetic

The legacy page assigned kidney-function categories, dose reductions, laboratory intervals, hydration rules, and stop thresholds. Those numbers were not derived from an administered-human MOTS-c renal study.

FDA's multidisciplinary review team summarized the central gap:

“The nominator did not submit, and FDA did not identify clinical studies that provided pharmacokinetic data for MOTS-c-related BDSs.”

The statement appears in FDA's July 2026 Pharmacy Compounding Advisory Committee briefing under “Pharmacokinetic Data.” It is a regulator's evidence finding, not an endorsement of MOTS-c or a dosing recommendation.

The Renal Claim Audit

The human kidney studies are real. Their exposure variable is the body's own peptide, not an administered product.

What the CKD Studies Found—and Did Not Test

Liu and colleagues studied skeletal-muscle and serum MOTS-c in people with stage 5 chronic kidney disease and reported altered endogenous levels and relationships with muscle features (PMID 31432706; DOI 10.1152/ajprenal.00202.2019).

Bolignano and colleagues later examined circulating MOTS-c as an endogenous biomarker in a hemodialysis cohort (PMID 39111290; DOI 10.1159/000540303).

Neither study administered MOTS-c. Therefore neither could measure:

• absorption or bioavailability;
• distribution volume;
• kidney excretion of a product;
• exposure at different eGFR levels;
• metabolite accumulation;
• removal during a dialysis session;
• a dose-response relationship; or
• adverse events caused by administration.

Endogenous concentration and exogenous disposition are different questions.

Figure 1

Two kidney-failure studies measured the body's own MOTS-c, and the blood results point in opposite directions

Text version of this diagram

1. Stage 5 chronic kidney disease (Liu et al.): People with stage 5 CKD (glomerular filtration rate below 15 mL/min) were compared with age-matched controls with normal kidney function. MOTS-c was lower in both skeletal muscle and serum in CKD.
2. 94 people on hemodialysis (Bolignano et al.): Circulating MOTS-c was higher than in controls, and higher still in the 53 people who died or had a non-fatal cardiovascular event during a median 26.5 months of follow-up.
3. What neither study did: Nobody received MOTS-c, so neither study measured absorption, kidney clearance or removal during a dialysis session. FDA's July 2026 review identified no clinical studies with pharmacokinetic data for MOTS-c.
4. What the levels cannot support: A low or high natural level in kidney failure does not show that giving MOTS-c would help or be safe, and it cannot be turned into an eGFR dose or a dialysis timing rule.

What a Renal Dose Recommendation Would Require

FDA's March 2024 renal-impairment pharmacokinetic guidance explains that impaired kidney function can alter a drug's pharmacokinetics and sometimes its pharmacodynamics. The purpose of a dedicated or adequately informative study is to determine whether and how dosing instructions should change.

For MOTS-c, a credible renal claim would need a characterized administered substance, human exposure data, kidney-function strata, timed concentration measurements, a validated assay, safety outcomes, and—where relevant—a dialysis sampling design.

None was identified. An eGFR table without those inputs is decoration, not pharmacology.

Figure 2

What FDA's March 2024 renal guidance asks a drug program to measure, and where MOTS-c stands at each step

Text version of this diagram

1. How the drug leaves the body: Guidance: a full study for drugs excreted mainly by the kidneys; a reduced study can serve drugs eliminated mainly by other routes. MOTS-c: FDA identified no clinical pharmacokinetic data, so how people eliminate it is not established.
2. Participants across kidney-function bands: Guidance Table 1 (eGFR, mL/minute): 90 or above as controls; 60 to under 90 mild; 30 to under 60 moderate; under 30 severe impairment or kidney failure not on dialysis. MOTS-c: FDA identified no human exposure data in any band.
3. Dialysis: Guidance: a hemodialysis study includes on- and off-dialysis periods and measures the drug in blood entering the dialyzer and in dialysate. MOTS-c: the hemodialysis cohort measured only the body's own peptide as a risk biomarker.
4. Dosing information: Guidance: the results feed the Prescribing Information for patients with impaired renal function. MOTS-c: none of the earlier steps has data, so there is nothing to feed an eGFR dose table.

Dialysis Status Does Not Answer Dialyzability

A person being on hemodialysis does not show that a substance crosses a particular membrane or is removed at a clinically meaningful rate. Dialyzability depends on factors such as molecular behavior, protein binding, distribution, membrane properties, session conditions, and the identity of the administered material.

The hemodialysis biomarker cohort did not dose MOTS-c before a session and calculate extraction or rebound. Its results therefore cannot support timing a product before or after dialysis.

Safety Uncertainty Has More Than One Layer

FDA found no human exposure data for MOTS-c by any route and raised separate concerns involving aggregation, peptide-related impurities, injection-related immunogenicity, and inconsistent substance identity. Kidney disease does not resolve those product questions.

The overdose-management audit explains why no exposure-response curve supports a toxicity threshold. The geriatric evidence review separates kidney function from chronological age, and the older-adult dosing page shows why a dose adjustment cannot precede a validated starting dose.

The Responsible Bottom Line

Published CKD and hemodialysis biomarker studies do not establish how administered MOTS-c behaves in kidney impairment. No evidence-based eGFR reduction, dialysis timing rule, fluid protocol, laboratory cadence, or stop threshold can be calculated from them.

Medical review of this revision is pending. FDA, investigators, institutions, journals, and study authors do not endorse MOTS-c, HealthRX.com, or this page.