Carnitine is a natural antioxidant that improves cellular energy metabolism. Low
carnitine levels may occur due to metabolic diseases or can be due to inadequate
nutritional intake of carnitine-containing foods [Stephnes et al, 2007]. Carnitine
supplementation has not been studied in individuals with PWS, but in other conditions
has been shown to improve hypotonia, ataxia, activity levels, and alertness. Infants and
young children with Down syndrome, who have muscle hypotonia and delayed growth
similar to that seen in individuals with PWS, have significantly lower carnitine levels than unaffected children of the same age, and supplementation with L-carnitine results in
significant increases in visual memory and attention in this population [Seven et al,
2001]. A subset of individuals with PWS have been found to have low serum carnitine
levels [Miller et al, 2010].
Carnitine is available in a variety of formulations, including L-carnitine (available over
the counter or as a prescription) and carnitine fumerate. Although no formal studies of
carnitine supplementation have been done, we have anecdotally heard that some
individuals have improvements in gross or fine motor skills and alertness with carnitine
supplementation. We recommend that you ask your physician to check a serum
carnitine profile to document whether or not carnitine deficiency is present. If the
carnitine levels are low on this profile, we recommend that the child have a urinary acylcarnitine profile measured. If the serum carnitine levels are low, we recommend a trialof supplementation with carnitine. Even if the serum carnitine levels are within the
normal range, some individuals still benefit from carnitine supplementation, and so we
recommend a trial of this medication for individuals with PWS.
Because prescription-grade products are FDA regulated, whereas over the counter
supplements are not, we prefer that children with PWS try the prescription L-carnitine.
The dose is typically 50 mg/kg/day divided twice a day. However, an evening dose of
carnitine keeps some children awake at night, so if this occurs, then once a day dosing
Start carnitine once other medication doses are stabilized, so that you are not changing
several medications or doses at the same time – this will allow you to determine if there
are benefits from the supplement. We recommend a 1 month trial of L-carnitine to
determine if there are benefits to the supplement for your child or not. If you discontinue
the carnitine and see negative changes in your child, then restart it. We recommend
trying carnitine if the child is taking less than 20 oz of formula or breast milk per day as
an infant or once the child has transitioned from formula to cow’s milk, soy milk, or
almond milk. Formula is fortified with carnitine, so provided your child is taking an
adequate amount of formula, the carnitine levels should be adequate. A list of carnitinecontaining foods is available from any dietician.