Acetyl groups are made of carbonyl and methyl groups. To improve bioavailability of a compound, attempting to add on either a methyl or acetyl group may help.

Depending on the compound, skipping this step may cause the compound to be relatively inert. This is why, for example, calcium carbonate is a poor source of calcium as a nutritional supplement, but calcium citrate is readily absorbed- the citrate itself is an organic compound, so the body more readily takes it up out of the digestive system and the calcium can be used.