Researchers from Suranaree University of Technology in Thailand say the combination appears to improve energy metabolism, reduce oxidative stress and upregulate key genes involved in mitochondrial biogenesis.
“These results indicate that these supplements, particularly in combination with exercise, may offer potential benefits for exercise performance and metabolic health,” they wrote in the journal Nutrients.
Ginseng and L-carnitine for exercise performance
Ginseng and L-carnitine are two supplements which have been extensively investigated for their potential ergogenic effects. This is namely because both have antioxidant properties—mitigating the effects of exercise-induced oxidative stress.
Previous research has shown that ginseng can increase endurance, reduce fatigue and improve recovery times. Multiple factors are thought to play a role in these benefits, including increased energy production and improved muscle function.
Conversely, L-carnitine transports long-chain fatty acids into mitochondria, where these fatty acids are oxidized to produce energy. This has been demonstrated in research which shows L-carnitine supplementation can positively affect exercise performance, particularly endurance-based activities.
Kakanang et al. therefore aimed to explore the potential benefits of this combination, as well as investigate alterations to glycogen content in the liver and muscles, blood biochemistry, antioxidant enzyme activity and gene expression.
Study details
In the study, 50 male Wistar rats were divided into 10 groups, including a control group and treatment groups, which consisted of either a low or high dose of one of the supplements, or a combination of the two.
The low dose groups received 250 mg/kg per day of ginseng extract or L-carnitine or both, while the high dose groups received 500 mg/kg. These doses were calculated by converting the human dose used in normal cases to the rodent dose.
Half of the groups were subjected to a 16-day exercise regime, while the other half remained sedentary. Endurance was measured at the end of the experiment in all groups using a tail-suspended forced swimming test.
Weight gain results differed across groups
Both ginseng extract and L-carnitine supplementation significantly increased exercise performance in both trained and untrained rats, enhancing endurance when taken separately and together.
In the exercise groups, 500 mg/kg of L-carnitine appeared to have the greatest benefit, yielding the longest post-exhaustion swimming time of 63 minutes, followed by 500 mg/kg of ginseng extract at 47 minutes.
In addition, sedentary rats who received ginseng or L-carnitine tended to gain less weight than controls, with the effect especially evident for L-carnitine.
However, the opposite effect was observed in the low-dose exercise groups, with rats supplemented with 250 mg/kg ginseng or L-carnitine gaining significantly more weight than rats in the other groups.
“These results suggest that the effects of ginseng and L-carnitine on weight gain may differ depending on the exercise status,” the authors explained.
Long-term effects?
The supplements also appeared to increase muscle and liver glycogen levels—a crucial process for exercise performance, as it fuels energy production.
No significant differences were found in the levels of blood glucose or insulin levels, however, a significant increase in creatine levels was observed in the sedentary high-dose groups, suggesting a potentially impact on kidney function.
“Potential mechanisms include renal clearance overload because of high L-carnitine doses, particularly in sedentary animals with potentially reduced renal function. Indirect effects such as disruptions to the electrolyte and fluid balance may also contribute,” the researchers wrote.
Finally, both supplements appeared to upregulate AMPK and PGC-1α gene expression, which play a role in regulating energy metabolism.
The researchers therefore conclude that ginseng and L-carnitine may offer potential benefits for exercise performance and metabolic health, but further studies are needed to evaluate the long-term effects.
Source: Nutrients. doi: 10.3390/nu17030568. “Role of Ginseng and L-Carnitine in Modulating Exercise Endurance and Oxidative Stress in Rats.” Authors: P. Kakanang, et al.
