L-Carnitine L-Tartrate
L-Carnitine L-Tartrate is a unrated form of L-Carnitine, used in 913 on-market products and providing 68.2% elemental l-carnitine by weight.
913
on-market products
unrated
quality tier
68.2%
elemental fraction
Basis: (C7H15NO3)2 x C4H6O6, 2:1 (2 x 161.20 / 472.49); matches real labels, e.g. a product declaring 1,466mg L-carnitine tartrate 'supplying 1,000mg L-carnitine' (0.682)
Why this tier: The form used in several RCTs (2g/day carnitine as LCLT in Volek 2008, 2g LCLT twice daily with carbohydrate in Wall 2011, which raised muscle carnitine 21%), but no human study compared tartrate directly with free L-carnitine or other salts.
Source: Volek JS et al. 2008, Am J Cardiol 102(10):1413-7, PMID 18993165; Wall BT et al. 2011, J Physiol 589(4):963-73, PMID 21224234