Supplement Label Index

Acetyl-L-Carnitine (ALC) vs. L-Carnitine Fumarate

Among 2,330 on-market l-carnitine products with an identifiable primary form, 27.6% use Acetyl-L-Carnitine (ALC) (644 products) and 8.8% use L-Carnitine Fumarate (205).

Acetyl-L-Carnitine (ALC)L-Carnitine Fumarate
Quality tierUnratedUnrated
L-Carnitine by weight79.3%58.1%
Share of market27.6%8.8%
On-market products644205
Median declared dose396.5 mg
middle half: 158.6–500
200 mg
middle half: 58.1–290.5
Most common brandsWonder Laboratories, Source Naturals, XYMOGENDr. Sinatra, Source Naturals, BulkSupplements.com

Doses are declared per serving in mg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).

Why Acetyl-L-Carnitine (ALC) is unrated

A different molecule from L-carnitine with its own evidence base (diabetic neuropathy, mood); no human study comparing ALC with L-carnitine on carnitine delivery or the same outcomes was located, so no tier is assigned.

Source: Sima AA et al. 2005, Diabetes Care 28(1):89-94, PMID 15616239

Why L-Carnitine Fumarate is unrated

No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.

Tiers summarize published comparative bioavailability or outcome evidence for each form (see methodology). This page describes the market; it is not a recommendation to take either form. Talk to a clinician about what's right for you.

Other l-carnitine comparisons