Effects of Carnosine Supplementation on Cognitive Outcomes in Prediabetes and Well-Controlled Type 2 Diabetes: A Randomised Placebo-Controlled Clinical Trial.

Hariharan R, Mousa A, Menon K, Feehan J, Ukropcová B, Ukropec J, Schön M, Majid A, Aldini G, de Courten M, Cameron J, Bell SM, de Courten B

Pharmaceuticals (Basel, Switzerland)26 Apr 2025Cited by 2 (Europe PMC)

PMID40430451PMCIDPMC12114902DOI10.3390/ph18050630PepBankPUB-40430451

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Summary

Background: Trends in global ageing underscore the rising burden of age-related cognitive decline and concomitant cardiometabolic diseases, including type 2 diabetes mellitus (T2DM). Carnosine, a naturally occurring dipeptide with anti-inflammatory, antioxidant and anti-glycating properties, has shown promise in animal models and limited human studies for improving cognitive function, insulin resistance and T2DM, but its therapeutic effects on cognition remain unclear. The aim of this study is to assess the effects of carnosine on cognitive function in individuals with prediabetes or well-controlled T2DM. Methods: This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks. At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB). Results: In total, 42 adults (23 males and 19 females) completed the trial. There were no differences in participant anthropometry or cognitive functioning between carnosine and placebo groups at baseline (all p > 0.1). After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05). Adjustments for baseline cognitive scores, diabetic status, level of education, age or interaction effects with participants' sex did not change the results. Conclusions: Carnosine supplementation did not improve cognitive measures in individuals with prediabetes or T2DM in this study. While larger trials may provide further insights, alternative factors-such as the relatively young and healthy profile of our cohort-may have contributed to the lack of observed effect. Future research should examine individuals with existing cognitive impairment or those at higher risk of cognitive decline to better define the therapeutic potential of carnosine in this context.

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

Results from this study5

5 results from studies that gave the peptide. 5 results from people.

01HumanRandomized controlled trialEfficacy outcome
In adults with prediabetes or controlled T2DM, Stroop change and follow-up scores did not differ between carnosine and placebo.
In plain wordsIn adults with prediabetes or controlled diabetes, Stroop scores did not differ between carnosine and placebo.
Peptide
L-carnosine
Outcome
No significant changeStroop test
Study
n = 42
Comparator
Identical placebo
Analysis
Secondary
Outcome group
Cognition and memory · Nervous system and cognition
Studied dose
2 g daily · 14 weeksAs given in this study (human).
Source sentences
Summary
After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05).
2 context sentences(design, population, supporting numbers)
Summary · context
This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks.
Summary · context
At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB).
Show in the study text Report a problemFND-4043045101
02HumanRandomized controlled trialEfficacy outcome
In adults with prediabetes or controlled T2DM, Digit Symbol Substitution change and follow-up scores did not differ between carnosine and placebo.
In plain wordsIn adults with prediabetes or controlled diabetes, Digit Symbol Substitution scores did not differ between carnosine and placebo.
Peptide
L-carnosine
Outcome
No significant changeDigit Symbol Substitution test
Study
n = 42
Comparator
Identical placebo
Analysis
Secondary
Outcome group
Cognition and memory · Nervous system and cognition
Studied dose
2 g daily · 14 weeksAs given in this study (human).
Source sentences
Summary
After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05).
2 context sentences(design, population, supporting numbers)
Summary · context
This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks.
Summary · context
At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB).
Show in the study text Report a problemFND-4043045102
03HumanRandomized controlled trialEfficacy outcome
In adults with prediabetes or controlled T2DM, Trail Making A change and follow-up scores did not differ between carnosine and placebo.
In plain wordsIn adults with prediabetes or controlled diabetes, Trail Making A scores did not differ between carnosine and placebo.
Peptide
L-carnosine
Outcome
No significant changeTrail Making A
Study
n = 42
Comparator
Identical placebo
Analysis
Secondary
Outcome group
Cognition and memory · Nervous system and cognition
Studied dose
2 g daily · 14 weeksAs given in this study (human).
Source sentences
Summary
After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05).
2 context sentences(design, population, supporting numbers)
Summary · context
This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks.
Summary · context
At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB).
Show in the study text Report a problemFND-4043045103
04HumanRandomized controlled trialEfficacy outcome
In adults with prediabetes or controlled T2DM, Trail Making B change and follow-up scores did not differ between carnosine and placebo.
In plain wordsIn adults with prediabetes or controlled diabetes, Trail Making B scores did not differ between carnosine and placebo.
Peptide
L-carnosine
Outcome
No significant changeTrail Making B
Study
n = 42
Comparator
Identical placebo
Analysis
Secondary
Outcome group
Cognition and memory · Nervous system and cognition
Studied dose
2 g daily · 14 weeksAs given in this study (human).
Source sentences
Summary
After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05).
2 context sentences(design, population, supporting numbers)
Summary · context
This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks.
Summary · context
At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB).
Show in the study text Report a problemFND-4043045104
05HumanRandomized controlled trialEfficacy outcome
In adults with prediabetes or controlled T2DM, CANTAB change and follow-up scores did not differ between carnosine and placebo.
In plain wordsIn adults with prediabetes or controlled diabetes, CANTAB scores did not differ between carnosine and placebo.
Peptide
L-carnosine
Outcome
No significant changeCANTAB cognitive measures
Study
n = 42
Comparator
Identical placebo
Analysis
Secondary
Outcome group
Cognition and memory · Nervous system and cognition
Studied dose
2 g daily · 14 weeksAs given in this study (human).
Source sentences
Summary
After the 14-week supplementation period, there were no differences between carnosine and placebo groups in change and follow-up values for any cognitive measures including Stroop, Digit Symbol Substitution Sest, Trail Making A/B or CANTAB (all p > 0.05).
2 context sentences(design, population, supporting numbers)
Summary · context
This is a secondary analysis of a double-blind randomised controlled trial (RCT), whereby 49 adults with prediabetes or early-stage well-controlled T2DM were randomised to receive 2 g of carnosine or identical placebo daily for 14 weeks.
Summary · context
At baseline and follow-up, cognitive function was assessed as a secondary outcome using the Digit-Symbol Substitution Test, Stroop test, Trail Making Tests A & B, and the Cambridge Automated Neuropsychological Test Battery (CANTAB).
Show in the study text Report a problemFND-4043045105

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

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

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Terms as the source lists them.

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