Table 3. Characteristics of the studies for omega-3 fatty acids as multi-ingredient formulas.

Author/Year/Country	Study design	Participants	Control treatment, No. of subjects (M, F)	Intervention, No. of subjects (M, F)	Duration of the intervention	Outcomes of interest	Risk of bias*
Rondanelli et al. [9]/2022/Italy	RCT-parallel, double-blind	• Sarcopenia patients aged ≥ 55 yr	n = 28	n = 22	8 wk	• Skeletal muscle mass	Some concerns
		• BMI range: 20–30 kg/m2	Isocaloric placebo with the same flavor	Omega-3 (323.5 mg of EPA, 147.1 mg of DHA, 29.4 mg of the other types of omega-3), formulated with leucine (2.5 g), probiotic LPPS23		• Skeletal muscle strength
Murphy et al. [35]/2022/UK	RCT-parallel, double-blind	• Older adults aged ≥ 65 yr at risk of sarcopenia	n = 28 (13 M, 15 F)	n = 30 (15 M, 15 F)	24 wk	• Skeletal muscle mass	Some concerns
		• BMI range: 25.1–27.1 kg/m2	10.6 g Whey protein and 3.1 g Leucine	Omega-3 (0.8 g EPA, 1.1 g DHA) formulated with leucine and whey protein		• Skeletal muscle strength
						• Physical performance
Scotto di Palumbo et al. [36]/2022/UK	RCT-parallel, double-blind	• Irish older adults aged 70 yr and above	n = 16 (8 M, 8 F)	n = 21 (11 M, 10 F)	24 wk	• Skeletal muscle mass	Some concerns
		• BMI range: 20–30 kg/m2	Placebo consisted of the fruit juice alone. contained whey protein isolate, vitamin D3, and resveratrol	Omega-3 (1.50 g EPA, 1.50 g DHA) in fruit juice		• Handgrip strength
Nilsson et al. [34]/2020/USA	RCT-parallel	• ≥ 65 yr of age, male sex	n = 16 (16 M)	n = 16 (16 M)	12 wk	• Skeletal muscle mass	Some concerns
		• BMI range: 20–34.9 kg/m2	Collagen protein 40 g/Sunflower oil 10 mL + HBRE	Omega-3 (1.51 g EPA, 0.95 g DHA) + HBRE		• Skeletal muscle strength

RCT, randomized controlled trial; EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid; BMI, body mass index; HBRE, home-based resistance exercise.

^*Risk of bias was assessed using a revised Cochrane risk-of-bias tool for randomized trials (ROB2).