In terms of analgesic potential anyway - http://jpet.aspetjournals.org/content/136/1/43 http://jpet.aspetjournals.org/content/136/1/43 Orally, Heroin has a bio

In terms of analgesic potential anyway - http://jpet.aspetjournals.org/content/136/1/43 http://jpet.aspetjournals.org/content/136/1/43 Orally, Heroin has a bioavailability of between ~25% and ~65%, depending on dose and tolerance, whereas Morphine has a bioavailability of 20-40%, making Heroin the more efficient of the pair.