L-carnitine: what it does and which foods have it

What it does

Carnitine helps move long-chain fatty acids into the mitochondria, where they are burned to produce energy. (NIH) Healthy adults make enough carnitine in the liver and kidneys, so it is not considered an essential nutrient and has no daily value.

Where you find it in food

Carnitine is found in animal products, especially red meat. (NIH)

Amounts are from the NIH Office of Dietary Supplements. Carnitine has no daily value.

How much you absorb

• Carnitine from food is about 63% to 75% bioavailable, while carnitine from supplements is only about 14% to 18% absorbed. (NIH)

Food, and where an IV fits

Food comes first. Most people get what they need from a varied diet, and a nutrient in food comes with fiber, protein and everything else the food carries.

An IV takes a different route. It delivers a nutrient straight into the bloodstream, so none of it depends on absorption in the gut. That can matter for people who absorb less, and your provider decides whether it is appropriate for you.

L-carnitine is in Performance and Longevity and is available as a core add-in ($40).

Who tends to run low

A typical omnivorous diet provides about 24 to 145 mg of carnitine a day; a vegan diet about 1.2 mg. (NIH)

The NIH lists these groups among those more likely to fall short:

• People with end-stage kidney disease on dialysis

A lab panel ordered by your provider can show your own levels. See lab testing before IV therapy.

Good to know

Doses around 3 grams a day of carnitine supplements can cause nausea, cramps and diarrhea. (NIH)