Table 1.

PICO for study inclusion

	Participants (P)	Intervention (I)	Comparison (C)	Outcomes (O)
Inclusion	Men and women of any age, ethnicity, geographic area, comorbidities or medication use	Carnosine and related HCDs (beta-alanine, anserine, NAC, etc) supplementation administered in any form (intravenous, intramuscular or oral), alone (pure) or combined with other intervention/s, of any dosage and for any duration	Placebo or usual care or any pharmacological or non-pharmacological interventions	All chronic disease risk factors and outcomes including but not limited to metabolic/glycaemic, cardiovascular and cognitive/mental health risk factors and outcomes
Exclusion	Studies not in humans	Studies without carnosine and/or HCD supplementation	Studies with no control group	None
Study type		RCTs and systematic reviews of RCTs
Language		No limit
Year of publication		No limit

HCDs, histidine-containing dipeptides; NAC, N-acetylcarnosine; PICO, Population, Intervention, Comparison, Outcomes framework; RCT, randomised controlled trial.