06/18/2026
We love L-Carnitine & Ascorbic acid & carry both 💙
Your cells burn two main fuels for energy: sugar and fat. Sugar gets into the mitochondria easily. Fat does not.
Long-chain fat is too big to cross into the mitochondrion on its own. It needs a chaperone. That chaperone is a small molecule called carnitine.
Carnitine grabs a fat molecule in the cell, walks it across the mitochondrial membrane, drops it off inside, and comes back out for the next one. Without carnitine, fat stays locked outside the mitochondria. Your cells default to running on sugar alone.
Your body makes carnitine in the liver and kidney. The process takes four steps, and two of those steps require vitamin C. Vitamin C keeps the enzymes that build carnitine working. When vitamin C runs low, those enzymes slow down. The body also starts losing carnitine in urine more quickly because vitamin C is needed to hold onto it. Either way, the carnitine pool shrinks.
This is the part most coverage of this topic gets wrong: vitamin C is not a fat-burning supplement. Taking more of it does not make you burn more fat. The mechanism only matters when vitamin C is actually low.
What matters is having enough. Around 200 mg a day, easy to hit from a red bell pepper, two kiwifruit, or an orange plus a cup of strawberries. That is enough to keep the carnitine system running. More than that does not give you more energy from fat. It gives you more expensive urine.
The point is not that vitamin C burns fat. The point is that the machinery your cells use to burn fat was built around vitamin C from the start. Get enough. You do not need more.
Rebouche, Am J Clin Nutr, 1991
Rebouche, Metabolism, 1996