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The answer is bioavailability
Those changes were however minor, compared to that of NAPstar4.3, and may be corrected for by subtraction (not performed here in the interest of full data transparency) ( Figure 4B,C )
For instance, this one measured the side effects of L-carnitine in a group of test subjects
5 A recent cohort study of NAD+ and a proprietary combination of B vitamins, amino acids, and DL-phenylalanine (an enkephalinase inhibitor) IV for substance abuse disorder found statistically significant improvement in cravings, anxiety, and depression scores for patients on IV NAD+.5 Another study on patients with alcohol or opiate addiction found doses of 500-1500mg per day (in combination with some vitamins, amino acids, and n-acetylcysteine) for 10 days to reduce cravings and number of relapses when patients were surveyed 12-20 months post treatment
Ongoing research into their bioactive compounds and mechanisms will be crucial for the complete realization of their therapeutic actions