L-carnitine is sold as a dietary supplement and also used as an injectable in clinical settings. The figures below reflect common supplement use and are for education, not a personal protocol. Injectable and IV use is a professional medical matter, not something to self-direct.
Overview
L-carnitine helps shuttle fatty acids into cells to be burned for energy. Most people get it from diet and their own synthesis. "Dosing" depends heavily on the form (oral supplement vs injectable) and on whether the goal is general supplementation or correcting a genuine deficiency.
Common amounts
Common, widely referenced amounts look like this:
- Oral supplement: commonly taken in the range of about 500 mg to 2 g per day, often split across doses.
- Injectable (clinic context): the commonly cited amount is up to roughly 500 mg–1 g per injection, given by a provider.
- In diagnosed carnitine deficiency, amounts are determined and monitored by a clinician and can differ from general supplement use.
These are supplement-context figures; they are not a treatment for any specific medical condition without professional guidance.
How it is administered
Oral L-carnitine is taken as capsules, tablets, or liquid. A relevant concept is that oral absorption of supplemental L-carnitine is limited compared with carnitine from food, so taking more does not translate simply into large changes in body levels in healthy people.
- Acetyl-L-carnitine is a related form with somewhat different properties.
- Injectable and IV preparations bypass the gut and are used in clinical settings by professionals.
Why oversight matters
For healthy people the case for high-dose supplementation is weak, and injectable/IV use should be handled by a clinician who can judge whether it is appropriate and monitor for effects. In true deficiency, dosing is a medical decision. A qualified provider is the right source for anything beyond routine over-the-counter supplement use.