L-Carnitine
Of 3,015 on-market l-carnitine products in the January 2026 DSLD dump, the median declared dose is 341 mg, and 28.7% list L-Carnitine L-Tartrate as the primary form.
Form share
Of 2,992 products with an identifiable primary form, here is the share held by each form of L-Carnitine on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| L-Carnitine L-Tartrate | Unrated | 859 | 28.7% |
| unspecified/undisclosed form | Unrated | 662 | 22.1% |
| Acetyl-L-Carnitine (ALC) | Unrated | 644 | 21.5% |
| Acetyl-L-Carnitine Hydrochloride | Unrated | 542 | 18.1% |
| L-Carnitine Fumarate | Unrated | 205 | 6.9% |
| L-Carnitine Hydrochloride | Unrated | 38 | 1.3% |
| Glycine Propionyl-L-Carnitine (GPLC) | Unrated | 17 | 0.6% |
| Propionyl-L-Carnitine | Unrated | 16 | 0.5% |
| Acetyl-L-Carnitine Arginate Dihydrochloride | Unrated | 9 | 0.3% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 2,140 products with a disclosed amount.
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- 60.7% of products fall below the fairy-dust threshold (400 mg, 20% of the studied low dose).
- 27.5% of products don't disclose an amount because L-Carnitine is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (mg) to see exactly how it compares to the 2,140 on-market l-carnitine products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for l-carnitine on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Label discloses only "Carnitine" with no salt or source form.
Elemental fraction: 68.2% ((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))
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
Elemental fraction: 58.1% (C7H15NO3 x C4H4O4, 1:1 (161.20 / 277.20); matches a real label: 862mg L-carnitine fumarate alongside 500mg L-carnitine (0.580))
No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.
Elemental fraction: 81.6% (C7H15NO3 x HCl, 1:1 (161.20 / 197.66))
No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.
Elemental fraction: 79.3% (C9H17NO4 inner salt, MW 203.24 (L-carnitine 161.20 / 203.24); expresses the L-carnitine equivalent of the declared ALC weight)
A different molecule from L-carnitine with its own evidence base (diabetic neuropathy, mood); no human study compares ALC with L-carnitine on carnitine delivery or the same outcomes, so no tier is assigned.
Source: Sima AA et al. 2005, Diabetes Care 28(1):89-94, PMID 15616239
Elemental fraction: 67.3% (C9H17NO4 x HCl, 1:1 (L-carnitine 161.20 / 239.70))
Same ALC molecule as a hydrochloride salt; no human comparison of salts.
Source: Sima AA et al. 2005, PMID 15616239
No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.
No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.
No head-to-head human bioavailability or efficacy comparison of this form was located in PubMed searches.
Reference values
- RDA (adult): not established — Endogenously synthesized; described in the literature as a conditionally essential amino-acid-like compound; no RDA/AI exists.
- Tolerable Upper Intake Level (adult): not established — No UL established. Hathcock JN, Shao A 2006, Regul Toxicol Pharmacol 46(1):23-8, PMID 16901595: Observed Safe Level of 2000mg/day L-carnitine equivalents for chronic supplementation (higher intakes tested without adverse effects but data insufficient). An OSL is not a UL. Separate mechanistic caution: gut microbiota convert oral L-carnitine to trimethylamine/TMAO, more extensively in omnivores than in vegans/vegetarians (Koeth RA et al. 2019, J Clin Invest 129(1):373-387, PMID 30530985).
- Studied clinical dose range: 2000–2700 mg
- Low end: Volek JS et al. 2008, Am J Cardiol 102(10):1413-7, PMID 18993165 -- randomized double-blind placebo-controlled crossover, 30 healthy adults, 2g/day L-carnitine (as L-carnitine L-tartrate) x3 weeks improved post-meal flow-mediated dilation (7.7% vs 5.8%, p=0.043); Bruls YM et al. 2019, EBioMedicine 49:318-330, PMID 31676389 -- 11 volunteers with impaired glucose tolerance, 2g/day L-carnitine x36 days (crossover) restored metabolic flexibility toward normal. High end: Wall BT et al. 2011, J Physiol 589(4):963-73, PMID 21224234 -- double-blind, 14 healthy men, 2g L-carnitine L-tartrate + 80g carbohydrate twice daily x24 weeks (4g/day of tartrate salt, about 2.7g L-carnitine by stoichiometry) raised muscle total carnitine 21% and, in the carnitine group, work output 11% in a performance trial. Acetyl-L-carnitine has its own trials, e.g. Sima AA et al. 2005, Diabetes Care 28(1):89-94, PMID 15616239 (two 52-week RCTs, ITT n=1,257, ALC 500 or 1,000mg, abstract states 't.i.d.'; improved nerve fiber regeneration and vibration perception; pain improved in the combined cohort taking 1,000mg). Meta-analysis: weight loss -1.33 kg vs control across 9 trials, n=911 (Pooyandjoo M et al. 2016, Obes Rev 17(10):970-6, PMID 27335245).
- Note: Single compound spanning L-carnitine, acetyl-L-carnitine (ALC), propionyl-L-carnitine and their salts: derivative forms are converted to L-carnitine equivalents with elemental_fraction (e.g. ALC x0.793) so doses are comparable, but ALC/PLC have distinct clinical uses (e.g. diabetic neuropathy) that the L-carnitine/LCLT studied range does not represent. Oral bioavailability of supplemental L-carnitine is low: 5-18% absolute after 1-6g doses vs up to 75% for dietary carnitine (Evans AM, Fornasini G 2003, Clin Pharmacokinet 42(11):941-67, PMID 12908852). Companion rows such as 'Supplying L-carnitine 1000mg' or 'from 862mg of L-carnitine fumarate' restate the salt row's carnitine content; they are intentionally not aliased to avoid double counting.