Melatonin is effective. At least for short periods of time and with respect to time zone changes and circadian rhythm shifts. The body naturally produces it, but external supplementation can shift the timing of the body's sleep cues when administered at low doses at the appropriate time. It is not a sedative and even higher doses does not make people fall asleep any faster. In fact, it can have the opposite effect. Valerian is a bit more hit or miss. People say they experience relaxation, but its mechanism of action is not well understood, and there are quite a few variables to account for in terms of its formulation and potency. It interacts with GABA pathways in the nervous system, which are related to both anxiety and muscle tone, but its bioavailability is highly variable. It might even help people fall asleep faster when stress and tension are running high, but I have never recommended stacking it with a prescribed sedative. L-theanine is probably the most underrated. It quiets the mind, but not in a sedative way. It smooths out spikes in alertness and, in small doses, can help people fall asleep with less mental chatter. It is good during the day, too, which is helpful for people whose sympathetic nervous system never seems to fully engage the brakes. In that way, it indirectly supports better nighttime rhythm by strengthening the regulation of the daytime. Magnesium has received more hype than it is due, unless the person taking it is known to be deficient. But certain forms of it (such as glycinate) can smooth out muscle tension and support parasympathetic nervous system dominance. If leg cramps, headaches, or daytime restlessness are issues, magnesium might have a meaningful impact. Outside of that, the effects are subtle at best. GABA is a total wildcard. It plays a huge role in inhibiting the central nervous system and, when an anxious person is finally able to calm themselves down at bedtime, the levels in the bloodstream do increase, which is likely why many people claim it works as a sleep aid. However, since supplemental GABA does not readily cross the blood-brain barrier, others have not been able to replicate those results. Chamomile is one of those "grandma's secret" things, but there is something to it. One of its active compounds, apigenin, binds to the same receptors that promote sleepiness. People do not generally become sedated by it, but their evening routine may become more normalized in response to taking it.