VITAL THC Tincture 250 mg

I started out with a third of a dropper under my tongue (as advised) increased to half, and on a second occasion used a full dropper. Except for being lethargic, this tincture did nothing for me. I had someone else try this, and their experience was like mine. If it's user error, I'd like to know how this product should be used and stored. Also, the bottle is VERY hard to open and close. Assuming this is supposed to be child-proof, but I don't think it opens or closes properly- it leaked each time I thought I'd closed it.