Dr Gundry's "Energy Renew" product should work to speed up recovery from exercise which should help fight fatigue. This product contains D-Ribose sugar at 5 grams. While the plant phytonutrients are a good addition, the 300 milligrams is far to low to really influence the body. 300 mg would fill about a third of an average size capsule. Vitamin C at 5 mg is also a very tiny amount. Average size orange has 70 mg of vitamin C. The Acetyl L-carnitine amount at 500 mg is a medium amount but would not yield significant effects on the average size body. Most studies use 3 times this amount. It is the dietary plan that goes along with this product that would achieve perhaps the majority of any weight loss.
Is this product 100% safe?
Any issue with this product becomes about potential side effects of the ingredients. And the tiny amounts of most nutrients limits this aspect to just one, D-Ribose. Yes, D-Ribose works to increase the ability of the body to build more ATP, the energy molecule. Ribose is normally built in the muscle cells from glucose. After ribose is used up during exercise, a recovery period is needed for ribose levels to slowly be built back up. Taking a supplement of ribose does speed up this recovery. BUT, there is a price associated with this help.
There is a process that speeds up the ageing of the body. This process is called glycation. ref The results of this process build up in the body elements called Advanced Glycation end products, or AGEs. AGEs simply increase the ageing speed. D-Ribose is one of the most reactionary sugars for producing AGEs. ref This is one of the fundamental aspects in Diabetes. Short term use of Ribose may be OK, but long term could be problematic. This aspect is overlooked by many Nutritionists, including in this case, also by Dr Gundry.
Natural foodstuffs that might slow down the glycation process, pLus a list of other references are found here> ref