Table 1.

PICOS criteria used to define the research question “Are there dietary supplements/ingredients that can be safely used to mitigate or reduce pain?”

Population	Individuals with pain, defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Pain is always subjective. Pain can be acute or chronic [3].
Intervention	Any dietary supplement/ingredient, defined as any product that met the following criteria: (a) any product (other than tobacco) intended to supplement the diet that contains one or more of the following ingredients: a vitamin, mineral, herb, or other botanical, an amino acid, a concentrate, metabolite, constituent, extract, or combination of any of these ingredients; (b) administered in any form (e.g., tablet, capsule, soft gel, gel cap, liquid, powder, gel, chews, inhalant, nasal spray, skin patches/lotions/applications); (c) not represented as conventional food or as a sole item of a meal or of the diet (e.g., sport drinks, shakes, bars); (d) included a “Supplement Facts” rather than “Nutrition Facts” panel [22, 23].
Control/comparison	Sham, no treatment and/or active comparators.
Outcome(s)	Pain and pain-related outcomes to address the multidimensionality of pain, i.e., physical function, sleep, mood, stress, cognitive performance, global health, health-related quality of life, behavior, and resource use outcomes, as well as adverse events.
Study design	Peer-reviewed research presented in the English language.

PICOS = Population, Intervention, Comparison, Outcomes and Study Designs strategy.