How about melatonin. Can get from iherb.com

Copy and pasting my reply from another similar thread:

I have a few suggestions for you:

1.) Read this book - Sleep: Redefine Your Rest, for Success in Work, Sport and Life. The author was the sleep coach for Manchester United and he talked about science of sleeping in this book.
2.) improve sleep hygiene - set a sleep/wake schedule and practice good sleep hygiene like no blue light exposure at least half an hour before sleeping.
3.) Download this app called Sleep Town - If you are like me, who have the habit of playing with phone in bed before sleep, check out this app. It's a game that lets you build buildings NOT TOUCHING YOUR PHONE when you are supposed to sleep and when you wake up on time.
4.) Breathing techniques - I think there is this breathing technique 1,4,2 breathing technique (google it) that's supposed to help increase the carbon dioxide in your blood and make you sleepy.
5.) And finally supplements:

Sleeping pills - not recommended for long term use!! Also, sleeping pills help you get into shallow sleep but not deep sleep. The sleep quality you get out of it is low.

Alcohol - not recommended. Like sleeping pill, it doesn't help promoting quality sleep.

Melatonin - not available in Malaysia. If you can get it and really want to use it, make sure your room is completely dark with no light. Melatonin is a chemical released by the brain and the brain stops producing it if there is light.

Chamomile Tea - This is the one that worked for me. Seriously, try it.

Magnesium - Magnesium is a relaxant. Can try, there are some evidence that it works - especially if you are deficient in magnesium. Note: Magnesium is lost through sweat, so deficiencies aremore common in athletes.

Lavendar - You can now get Lavendar supplements (oral supplements, not aromatherapy). The other name of it is called Silexan. I have seen it in Australia before but not yet in Malaysia. Note: it has estrogenic （female hormone) properties, so if your breasts start getting tender (gynecomastia) after taking it, you should stop.

Valerian - it's a popular supplement for sleep but I think many find it useless. Worth trying though, might work for you.

3 remedies recommended by Tim Ferriss in his book Tools of Titans

1.) Honey + Apple Cider Vinegar: 2 tablespoons of apple cider vinegar and 1 tablespoon of honey, stirred into 1 cup of hot water. I haven't tried this and will try it and let you know if it's effective.

2.) Yogi Soothing Caramel Bedtime Tea: You can get this online. In fact, I have just ordered it online and will try it and update on its effectiveness.

3.) California Poppy Extract: A few drops of California Poppy extract in warm water. Apparently it's the strongest tranquilizer of the three, I'm probably not gonna need this (lol.....)