I have taken the amino acid GABA for other reasons other than inducing lucid dreaming but as a way to stimulate my serotonin levels. Upon taking it, I realized it really effects the vividness and lucidiy of dreaming.
My suggestions is taking one capsule of 500 mg GABA before bed time. I guarentee you if it doesn’t help you induce a lucid dream it will definately aid in dream recall and the vividness in your dreams.
Some herbal supplements which can stimulate sleep is valerian root. Mix the mother tincture (at least half dropper full) in less than 1/2 cup of water.