The Effect of Carnosine Supplementation on Depressive Symptoms and Health-Related Quality of Life in Individuals With Prediabetes and Well-Controlled Type 2 Diabetes: A Randomized Controlled Trial.

Kabthymer RH, Feehan J, Mousa A, Aldini G, de Courten M, Cameron J, de Courten B

Food science & nutrition25 Feb 2026

PMID41767833PMCIDPMC12935567DOI10.1002/fsn3.71514PepBankPUB-41767833

Summary

Type 2 diabetes mellitus (T2DM) is commonly associated with mental health disorders such as depression and anxiety. Carnosine, an over-the-counter food supplement, may improve depressive symptoms through its anti-inflammatory properties; however, its effects on depressive symptoms and quality of life in prediabetes or T2DM remain unexplored. This randomized controlled trial aimed to examine whether carnosine supplementation may improve depressive symptoms and quality of life among individuals with prediabetes and well-controlled T2DM. A total of 38 participants (73.6% male) with a median (IQR) age of 54.8 years (46.2, 59.4) and mean ± SD body mass index (BMI) of 29.0 ± 4.2 kg/m² were randomized to carnosine (n = 18) or placebo (n = 20) for 14 weeks. None of the patients were diagnosed with depression or anxiety or any other chronic disease other than prediabetes (n = 20, 52.6%) and T2DM (n = 18, 47.4%), the latter being well-controlled with diet or metformin only. Depressive symptoms were measured using the patient health questionnaire (PHQ-8) and health-related quality of life was measured with five-dimension EuroQoL three level (EQ-5D-3L) scale. Paired t-tests were employed for within-group comparisons. Analysis of covariance (ANCOVA) was used for between group comparisons adjusted for age, BMI, and baseline values. Carnosine supplementation resulted in improvement of depressive symptoms assessed by total PHQ-8 score (mean difference = -2.0; 95% CI: -3.9, -0.2; p = 0.03), compared with placebo. However, the eight subcomponents of the PHQ-8 scale did not show significant changes (p > 0.05). There were no significant changes both in between-group and within-group comparisons in health-related quality of life scores (p > 0.05). We demonstrated for the first time that carnosine supplementation resulted in a modest improvement in depressive symptoms in individuals with prediabetes or T2DM. Further studies are needed to corroborate these findings in larger cohorts with more diverse baseline risk profiles. Trial Registration: NCT02917928.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study3

3 results from studies that gave the peptide. 3 results from people.

01HumanRandomized controlled trialEfficacy outcome
In participants with prediabetes or controlled type 2 diabetes, carnosine improved PHQ-8 scores versus placebo (mean difference -2.0).
In plain wordsIn participants with prediabetes or controlled diabetes, carnosine improved depression symptom scores compared with placebo.
Peptide
L-carnosine
Outcome
DecreasePHQ-8 total score
Study
n = 38
Comparator
Placebo
Outcome group
Anxiety and mood · Mental health and mood
Studied dose
Dose not stated · 14 weeksAs given in this study (human).
Measurements
Mean difference in total PHQ-8 score versus placebo
−2 PHQ-8 total score
carnosine versus placebo, ANCOVA adjusted
95% CI of mean difference in total PHQ-8 score
−3.9 to −0.2 PHQ-8 total score
carnosine versus placebo
Source sentences
Summary
Carnosine supplementation resulted in improvement of depressive symptoms assessed by total PHQ-8 score (mean difference = -2.0; 95% CI: -3.9, -0.2; p = 0.03), compared with placebo.
1 context sentence(design, population, supporting numbers)
Summary · context
A total of 38 participants (73.6% male) with a median (IQR) age of 54.8 years (46.2, 59.4) and mean ± SD body mass index (BMI) of 29.0 ± 4.2 kg/m² were randomized to carnosine (n = 18) or placebo (n = 20) for 14 weeks.
Show in the study text Report a problemFND-4176783301
02HumanRandomized controlled trialEfficacy outcome
In participants with prediabetes or controlled type 2 diabetes, carnosine did not significantly change the eight PHQ-8 subcomponents.
In plain wordsIn participants with prediabetes or controlled diabetes, carnosine did not significantly change any of the eight individual depression symptom scores.
Peptide
L-carnosine
Outcome
No significant changePHQ-8 subcomponents
Study
n = 38
Outcome group
Anxiety and mood · Mental health and mood
Studied dose
Dose not stated · 14 weeksAs given in this study (human).
Source sentences
Summary
However, the eight subcomponents of the PHQ-8 scale did not show significant changes (p > 0.05).
1 context sentence(design, population, supporting numbers)
Summary · context
A total of 38 participants (73.6% male) with a median (IQR) age of 54.8 years (46.2, 59.4) and mean ± SD body mass index (BMI) of 29.0 ± 4.2 kg/m² were randomized to carnosine (n = 18) or placebo (n = 20) for 14 weeks.
Show in the study text Report a problemFND-4176783302
03HumanRandomized controlled trialEfficacy outcome
In participants with prediabetes or controlled diabetes, quality of life did not change significantly between groups or within groups.
In plain wordsIn participants with prediabetes or controlled diabetes, quality of life did not change significantly compared with placebo or baseline.
Peptide
L-carnosine
Outcome
No significant changeHealth-related quality of life
Study
n = 38
Comparator
Placebo
Outcome group
Quality of life · Whole body
Studied dose
Dose not stated · 14 weeksAs given in this study (human).
Source sentences
Summary
There were no significant changes both in between-group and within-group comparisons in health-related quality of life scores (p > 0.05).
1 context sentence(design, population, supporting numbers)
Summary · context
A total of 38 participants (73.6% male) with a median (IQR) age of 54.8 years (46.2, 59.4) and mean ± SD body mass index (BMI) of 29.0 ± 4.2 kg/m² were randomized to carnosine (n = 18) or placebo (n = 20) for 14 weeks.
Show in the study text Report a problemFND-4176783303

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Registered trials1

Trials this study reports on, or that list this study as a reference. Registry data from ClinicalTrials.gov.

1 trial · source ClinicalTrials.gov (opens in a new tab)

Status unknownPhase 2NCT02917928

The Potential of Carnosine Supplementation in Optimising Cardiometabolic Health

Monash Universityn = 40Oct 2016 to est. Jul 2023

Poor Glycemic Control · Cardiovascular Risk Factors · Cognitive Function 1, Social

Trial page ClinicalTrials.govUpdated 28 Jun 2022

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
27 Oct 2026, 18:20 UTC
Study results updated
Version 1
27 Oct 2026, 16:32 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

Publication types

Keywords

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