Dylan is the man to answer that one, I frankly cannot remember. I did a log for Pure Essence a while back and love it. I also did a test about how horrible the vision sides would get with stupid doses of S4 - they get very bad. I work from home a lot, so I picked a several week period where I knew I would not have to drive after dark (and during the summer - so long hours of light). S4 vision sides are not bad at the recommended doses, but like Dylan always says, more is NOT better. So when he gives you doses, you can always safely drop, but ask before increasing.