Key Topics Covered
- L-Carnitine is a naturally occurring amino acid that is proposed to help with a wide variety of functions.
- A lot of people take it for the purpose of fat loss. In this podcast, we will explore how effective it is for that.
- L-Carnitine helps with fat transportation in the body. It transports fatty acids to the mitochondria.
- This is part of why people are interested. However, fat transportation does not necessarily directly translate to fat loss.
- A systematic review from 2016 looking at 9 randomized controlled trials on the topic found an average of 1.3kg lost while taking L-Carnitine vs placebo.
- A positive interpretation of that is that 1.3kg is better than zero. But some skepticism is worthwhile.
Reasons for Skepticism
- A study that had 36 women had 5 participants completely drop out due to nausea and diarrhea. That’s pretty relevant. Those symptoms would typically contribute to weight loss directly or indirectly due to reduced desire to eat.
- Publication bias. Supplement studies always deserve some level of skepticism.
- Absorption levels of L-Carnitine are really low. If it’s barely absorbed, how will it help?
- >95% of the body’s carnitine is located within the muscle.
- Those who are plant-based have lower intakes of carnitine and carnitine precursors. They therefore also have lower baseline levels.
- Research typically finds that oral supplementation of carnitine doesn’t significantly increase the body’s carnitine stores in omnivores.
- For example, one study involved supplementing 2g per day for 12 weeks, and there was no difference in muscle stores in omnivores.
- That same research DID find a 13% increase in muscle stores in those who were vegetarian though.
- The minimal change in absorption overall is a large portion why it makes sense to be skeptical about the effectiveness.
How to Increase Absorption
- Firstly, the absorption issue is less of a factor in those who are plant-based.
- But there are some ways around it.
- One study used 2g of L-Carnitine alongside 80g of simple carbs, 2x per day (so double those total amounts). Participants were omnivores and their carnitine stores increased by 21%.
- The issue here is that adding 160g of simple carbs to a diet to get a 21% increase in carnitine stores could be counterproductive.
- Another way around this could be injecting carnitine instead of oral supplementation – but that’s outside of our area.
L-Carnitine is pretty rare to have a significant impact on fat loss. However, it may be more relevant if you are plant-based or taking a large amount of carbohydrates alongside it.
Relevant Blogs / Resources