I always required about 10 hours of sleep. Sleeping less during the workweek created a cumulatively increasing sleep debt; Friday was a constant battle to not fall asleep. On weekends I was sleeping up to 15 hours repaying the sleep debt. Pretty shitty arrangement.

After years of trying, I finally found something that allows me to sustainably sleep less. Every morning I take:

250mg nicotinamide riboside

400mg SAM-E

Now I automatically wake up after 6.5h-7h of sleep, a massive difference. It works reliably for 4 months now and I haven't observed any sleep debt, so I don't think any stimulant-like effects are the cause.

The change was occurring gradually as I started taking NR (I was already taking SAM-e). I first noticed shorter sleep about 3 days in, full reduction was obtained in about 14 days.

I did a two-week experiment and cut SAM-e out, taking only NR. At the end my natural sleep length increased to ~8.5h. At that point I resumed taking SAM-e.

SAM-e alone had no sleep shortening effect.