Jojo,
I don't know how to purchase it, but Google the name and their web-site is the first link. They have a "Contact Us" link so you can ask them directly about purchasing it.
If you go to their "Research and Technology" tab, click on the section titled "Validation" that lists the clinical trials.
If you want to see if their work has been published and peer reviewed, go here and type in Optalert for the search:
Link to Peer Reviewed and Published Scientific Articles
Vicki
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That which does not kill you makes you stronger-Friedrich Nietzsche
Friedrich must of had apnea.