Table 4.

Articles included in the systematic review that investigated the effect of l-Carnitine on low–moderate-intensity (50–79% $\dot{\mathrm{V}}$O_{2 max}) athletic performance variables.

Author/s	Population	Intervention	Outcomes Analyzed	Main Results
Chronic l-C supplementation
Broad et al., 2005 [30]	15 endurance-trained men (20 to 46 years)	3 g of l-CLT (2 g l-C) Duration: 4 weeks and 2 weeks washout period between them	90 min at 65% $\dot{\mathrm{V}}$O2 max on cycle ergometer:
			Borg scale	↔
			$\dot{\mathrm{V}}$O2	↔
			20 km time trial duration: Total time trial
			Total time trial	↔
Smith et al., 2008 [34]	32 untrained participants (9 men and 23 women (18 to 44 years)	1 g/day of PL-C n = 11 3 g/day of PL-C n= 12 Duration: 8 weeks	Aerobic exercise test on the treadmill:	GPL-C-1	GPL-C-3
			Borg scale	↔	↔
			$\dot{\mathrm{V}}$O2 peak	↔	↔
			Total exercise time	↔	↔
Wall et al., 2011 [23]	14 Moderately trained recreational athletes (25.9 ± 2.1 years)	4 g of l-CLT (2,72 l-C) with 160 g of CHO distributed 2 times per day (1 at breakfast and 4 h later Duration: 24 weeks	Test on cycle ergometer at 50% $\dot{\mathrm{V}}$O2 max:	week 12	week 24
			Borg scale	↔	↔
Acute l-C supplementation
Colombani et al., 1996 [20]	7 endurance-trained men (36 ± 3 years)	2 g of l-C 2 h before the marathon and 2 g of l-C after 20 km 125 mL of sugar tea every 5 km and 500 mL during the next hour after the marathon	Marathon:
			Total time	↔
Burrus et al., 2018 [24]	10 moderately active men (27 ± 4 years)	3 g of l-C + 200 mL of H2O 3 h before the exercise 94 g of CHO in 500 mL of H2O 2 h before the exercise 94 g of CHO in 500 mL of H2O 30 min before the exercise	Test on cycle ergometer at 65% $\dot{\mathrm{V}}$O2 peak:
			Power at 0, 10, 20, 30 y 40 min	↔

Legend: ↔ no difference in effects between groups (p > 0.05); CHO: carbohydrates; l-CLT: L-Carnitine l-tartrate; l-C: l-carnitine; PL-C: propionyl l-carnitine.