The three guidelines [3,4,9] do not indicate when to use sleeping pills. However, it is very important to take into account the time a patient is taking sleeping pills. Patients usually want to fall asleep quickly right after taking sleeping pills. To maximize the effect of sleeping pills, patients should take them at “sleep time taking into account the sleep-wake cycle,” not “when patients want to sleep.” In a study investigating the relationship between timing of sleeping pill administration and subjective satisfaction, the satisfied group had 7.2 hours and 9.3 hours between pill administration and wake-up time (PTW) in the dissatisfied group . Based on these results, the same researchers suggested taking sleeping pills 7 hours before waking up instead of 30 minutes before bedtime to increase patient satisfaction . As there are individual pharmacodynamic and pharmacokinetic differences and limited evidence of their effects is limited, these suggestions may not apply to all patients. It is important to note that patients are likely dissatisfied with the instructions to take their medications 30 minutes before bedtime. It is recommended to take extended-release melatonin one to two hours before bedtime. The concentration of extended-release melatonin peaks 1.6 to 2.6 hours after ingestion . Given the duration of action of the drug and sleep-wake cycles, doctors may give instructions to take sleeping pills nine hours before waking up in the morning and going to bed two hours later.
I do not think it is illegal. When I lived in Korea, I bought it from a foreign grocery store. The Narcotics Policy Division of the Korean Food and Drug Administration (KFDA) states that all drugs containing narcotics (including CBD oil) are strictly prohibited from importation into Korea, even with a doctor`s prescription. For other prescription drugs, visitors must submit a written request to the Narcotics Control Department of the Korea Food and Drug Administration (KFDA) prior to travel. Please contact KFDA for the application process and updated information at +82-43-719-2813 or email email@example.com. China announced last December that coenzyme Q10, fish oil, melatonin, spirulina and the fungus Ganoderma lucidum would be officially added to the directory of health food raw materials on March 1 this year. It seems that melatonin is a complex subject in Seoul. To begin with, this hormonal drug is not available in local pharmacies. However, it can be prescribed by a doctor. Before trying stronger sleeping pills like Stilnox, Ambien or Zolpidem, try to access melatonin or try things that can induce sleep. This is because melatonin is not addictive – it is a natural hormone that humans produce regularly.
In addition, various factors can contribute to the incentive to sleep: exercising, changing bedding and pillows, closing blinds at the right time, reducing screen time to blue light, and avoiding eating right before bed. However, sleep is extremely important, and everyone is advised to sleep AT LEAST eight hours a night. If you really need to resort to these sleeping pills, do it with caution. Sleep is a top priority. I was in Korea 3 months ago, no problem with introducing my melatonin in sleep disorders can be treated with zolpidem CR or antidepressants such as doxepine and trazodone. Patients 55 years of age or older may also use an extended-release formulation of melatonin. Although suvorexant has not yet been introduced in Korea, it is also recommended for sleep disorders. Someone once (somehow) managed to kill themselves with melatonin – that`s the only reason I can think of for their strange status here. Ramelteon is a melatonin receptor agonist approved by the U.S. FDA for the treatment of insomnia and recommended by AASM (2017) guidelines  for sleep-induction insomnia. According to AASM (2017) , unlike Ramelteon, the use of melatonin supplements for sleep induction or maintenance insomnia is not recommended due to insufficient evidence of efficacy. The ESRS (2017)  and ACP (2016)  do not recommend the use of melatonin for insomnia for the same reason.
However, the above guidelines did not clearly distinguish extended-release melatonin from fast-acting supplements. Melatonin prolonged-release drugs do not act on GABA receptors, so compared to benzodiazepines or BzRAs, they have fewer side effects such as decreased cognitive function, falls, rebound insomnia, dependence, tolerance and withdrawal symptoms. It is not illegal to buy melatonin in South Korea.