I was reading about L-carnitine tartrate and came across this article in relation to a patent. Seems to imply there is potential for some toxicity issues with the tartrate form of carnitine which I have not read anywhere elese, however not entirely sure how legitimate this is bearing in mind it seems to be promoting another form of carnitine(which I guess the applicants are trying to patent)

heres the article from patentstorm.

The present invention relates to a method for reducing and counteracting
gastrointestinal disorders brought about by the intake of L-carnitine in
an individual in need thereof. More specifically, the present invention
relates to a method for reducing and counteracting increased volume and
fluidity of stools and frequency of bowel movements relative to the
individual's usual pattern following intake of exogenous L-carnitine for
therapeutic, nutritional or dietetic purposes.

As is well known, therapeutical uses of L-carnitine inner salt
(hereinbelow, simply "L-carnitine") have long since been known. For
instance, L-carnitine has been used in the cardiovascular field for the
treatment of acute and chronic myocardial ischaemia, angina pectoris,
heart failure and cardiac arrhythmias.

In the nephrological field, L-carnitine has been administered to chronic
uraemic patients undergoing regular haemodialytic treatment to combat
myasthenia and the onset of muscular cramps.

Other therapeutic uses relate to the normalisation of the HDL:(LDL+VLDL)
ratio and total parenteral nutrition.

Besides the aforesaid uses in the therapeutical field, L-carnitine has
increasingly established itself on the so-called health food, medical food
or nutraceutical market. These terms, which have yet to be rigorously
defined from the regulatory point of view, denote foods or food components
such as food supplements, dietetic products, energy foods, and the like,
i. e. formulations which are not addressed to mainly or exclusively
therapeutic purposes but which are aimed rather at enhancing well-being
and at producing a general improvement in ****ceutical
compositions, in particular solid compositions, which, differently from
L-carnitine- or L-carnitine L-tartrate containing compositions, are
totally free of gastrointestinal adverse effects.

A study on the effect on intestinal motility of L-carnitine acid fumarate
vs. L-carnitine L-tartrate administered by the oral route to the rat at a
single dose, using the charcoal propulsion test, is hereinbelow reported.

35-day old, Hsd Sprague Dawley (SD) male rats (Harlan), weighing 125-150 g
were used in the study. The rats were supplied by Harlan Nossan S.r.l., 8,
Via E. Fermi, 20050 Correzzana (MI)--Italy.

Eight male rats/group were treated orally with L-Carnitine acid Fumarate,
at the doses of 430-855 and 1710 mg/10 ml/kg, and with L-Carnitine
L-Tartrate at the doses of 365-730 and 1455 mg/10 ml/kg.

The doses of the two compounds were chosen as equimolar to 250-500 and 1000
mg/kg of L-Carnitine Inner Salt.

Two additional groups, each consisting of eight males, were set up and
orally treated respectively with the vehicle (Control group--0.5%
Carboxymethylcellulose (MC) in deionized water: 10 ml/kg) or with Atropine
(30 mg/10 ml/kg) as reference standard.

The animals were subdivided at random (in number of 4/cage) into the
different dosage groups according to the following scheme:

GROUP ORAL TREATMENT DOSE 1 Vehicle (0.5% CMC) -- 2 L-Carnitine Fumarate 430 3 L-Carnitine Fumarate 855 4 L-Carnitine Fumarate 1710 5 L-Carnitine Tartrate 365 6 L-Carnitine Tartrate 730 7 L-Carnitine Tartrate 1455 8 Atropine Sulphate Salt 30

Forty-five minutes after the administration of all the above reported
substances, each rat received orally 1.5 ml of a 10% charcoal suspension.

Exactly twenty minutes after dosing with charcoal suspension the rats were
sacrificed; then the distance the charcoal meal had travelled throughout
the intestine (from the pyloric sphincter towards the caecum) was measured
and expressed as a percentage of the total gut length.

Results (see Table 1 and Appendixes 1a through 1d)

L-Carnitine acid Fumarate

No statistically significant differences were seen between the treated
groups and the one receiving the vehicle for the distance travelled by
charcoal, as % of total intestine length. No particular trend was seen for
the different doses administered.

L-Carnitine L-Tartrate

As for the L-carnitine L-tartrate, a statistically significant (p<0.05)
increase of gastrointestinal motility was seen in the middle and high
dosage groups (730 and 1455 mg/kg, respectively) when compared with
control group; an evident relationship between the administered dose and
the distance the charcoal had travelled throughout the intestine was
present.

Atropine

The group treated with Atropine (30 mg/kg) showed a statistically highly
significant (p<0.001) decrease in gastrointestinal motility, as
expected.

CONCLUSIONS

In conclusion, under the adopted experimental conditions the test article
L-carnitine acid fumarate administered orally in single dose to the rat
did not cause a change in gastrointestinal motility at any tested dose.

As for the L-carnitine L-tartrate a statistically significant increase in
gastrointestinal motility was detected in the middle and high dosage
groups, when compared with controls, with an evidence of
dose-relationship.

Nasser Oil Sonbaty