Had a customer the other day that asked a question about one of my favorite supplements, L-Theanine.
Concern was that they saw it can lower blood pressure and will this interact with medications they're already taking for that. Usually it's a simple consult your doctor and don't take blood thinners when you're already on pharmaceutical blood thinners. And under DSHEA (the American Dietary Supplement and Health Act of 1994), as a retail employee who is not medically licensed, I can't actually say much more than that. But I can state facts and beat around the bush a little.
L-Theanine is not known to act as a blood thinner or to physiologically interact with the cardiovascular system directly. It is an amino acid originally find in tea that is a precursor to the neurotransmitter GABA, which is most frequently found in the parasympathetic nervous system. Studies have found it might be helpful in the management of anxiety and stress, which can help support healthy blood pressure (can't tell people that something will reduce blood pressure). I've never heard of it having interactions with other types of medications, but given how brain chemicals are double check with your doctor if you have concerns.
So yeah, respect retail workers or whatever because something something no such thing as unskilled labor and we're just trying to help you but also sometimes there are things we legally cannot say to answer your questions.
