Can liquid glucosamine supplements like flexicose and synflex help with spinal stenosis?

No. These substance studied for knee and hip barely beat placebo for arthritis pain in those two joints your nerves need more not more cartilage I dont see how it could help.
No. Spinal stenosis symptoms are due to pressure on nerves in the spine. Gllucosamine, in theory, helps preserve/restore with cartilage in arthritic joints and would not have any effect on spinal stenosis symptoms.

Related Questions

Do liquid glucosamine supplements? Help with spinal stenosis?

No evidence for this. Glucosamine & chondroitin are supplements that some believe help osteoarthritis pain (facet joint arthritis in spine); studies have shown mixed results; the american academy of orthopedic surgeons recommend against prescription of these for knee oa as a randomized controlled trial showed no benefit; there is no evidence that they help w/ spinal stenosis; see a spine specialist for treatment recs.

Can you please tell me some creative natural foods to help alleviate or even reverse spinal stenosis? I already know about glucosamine, omega 3s, etc.

Supplements. Depending on the cause of your spinal stenosis there may not be foods that can reverse this. However foods with turmeric or curcumin are natural anti-inflammatories that may alleviate some of your pain.