Careful studies have been conducted to see if increasing nitric oxide can improve neurological outcomes in stroke cases.

In one study, researchers selected patients who had been treated with drugs to increase nitric oxide within six hours of suffering a stroke.

They observed significant improvement in disability scores, quality of life, cognition, and mood. There were also fewer deaths.

Using animal models that resembled human strokes, researchers found that drugs that block nitric oxide generation in the brain — if given before the stroke — were also protective.

That finding seemed to contradict the findings of prior studies.

The reason for this seemingly contradictory outcome may lie in the timing of exposure to nitric oxide.

Another problem with these studies was that the drug used to block nitric oxide production inhibited all three forms of NOS enzyme, and eNOS is actually beneficial in the case of a stroke.

By using a drug that only blocked iNOS — the most damaging form of the enzyme — researchers found significant improvement in the outcomes of animals with models of human strokes.

Another study found that blocking nNOS and eNOS also protected the brain during a stroke.

It’s likely that the benefits came mostly from blocking nNOS, which is the neuronal form of the enzyme.

As noted, if nitric oxide was given promptly after the stroke, it improved recovery and made the area of brain damage smaller.

It was hypothesized originally that the nitric oxide — if it was given promptly — improved blood flow in the brain and protected the area around the worst of the damage.

But in fact, the benefit seems to have little to do with blood flow in the brain.

Rather, it is the ability of nitric oxide to prevent accumulation of glutamate around the synapse, which it can destroy through excitotoxicity, that actually protects the brain.

Because we still do not know the exact timing that would be best for raising brain nitric oxide or blocking it, I suggest maintaining normal levels of nitric oxide through proper diet, and avoiding supplements that might make things worse.