Phenibut is the hallmark anti anxiety nootropic developed by the Russians as part of the USSR Cosmonauts medical kit. Like Russian Vodka, this stuff kicks like a donkey. Phenibut completely crushes anxiety while allowing the brain to operate on a normal level. Compare this to your standard run of the mill benzodiazepine like Xanax and you’ll see why Phenibut is a far superior compound. Phenibut delivers all the benefits of traditional anti anxiety medications without burning your brain to a crisp.

How long does Phenibut take to kick in?

Phenibut (if you get the real thing) takes quite a while to kick in compared to other nootropics and compounds. Generally you can expect to feel some effects at hour 1 with the full onset of effects kicking in at the second hour. How fast Phenibut kicks in will depend on a number of factors. Most importantly, if you take Phenibut after eating or on a full stomach this could potentially delay the onset. I find that the Phenibut is much stronger if taken on an empty stomach. If I want to get the most bang out of my Phenibut capsules I will take them on a completely empty stomach and drink coffee. The acidic nature of the coffee seems to enhance the Phenibut experience. Coffee and Phenibut go together very smooth. You can drink coffee all day and experience zero negative side effects of the caffeine.

As always, your mileage may vary.

Duration of effect

The half life of Phenibut is 5.3 hours meaning it takes 5.3 hours for half the drug to leave your system. Phenibut is a very long lasting compound. Effects are often felt for the entire duration of the day and there’s a 24 hour after glow the next day. The most notable effects of the Phenibut will be at hours 2 – 7 after ingestion with a subtle drop off in intensity throughout the day. Phenibut lets you down slowly unlike caffeine or most stimulants. With many compounds there’s a sudden high and then a crash. With Phenibut there is no crash, only a slight tapering off of the total experience. Like an ever so slight shaving off of energy.

The next day

The following morning of taking the Phenibut you will either feel like garbage or you will still feel good. For many individuals including myself I can still feel Phenibut well into the next day. This is called the Phenibut after glow. It’s kind of like still feeling the alcohol you drank from the night before except it’s not a drunk feeling. It’s a nice calm and relaxed energy that gives way to a slight rebound anxiety later. Make no mistake, there is a toll that must be paid for using Phenibut. As the old saying goes, what goes up, must come down.

48 hours after taking the Phenibut you might experience something similar to an alcohol hangover, although in my experience alcohol is far more toxic and debilitating to the body. Chances are high if you’re taking Phenibut for anxiety you will no doubt feel an anxiety rebound. This is the chemicals in your brain attempting to rebalance themselves after being artificially inflated by Phenibut. The body feels just slightly depleted and there is an underlying low level depression. Of course this is all dependent on how you react to Phenibut and your dosage. If you take a low dose of let’s say 500mg, there may be little to no negative side effects after the Phenibut leaves your system. However, if you are taking 1G doses multiple times a day for a week then this is obviously going to have a more intense backlash against you.

In this way Phenibut is a double edged sword but can be managed. After coming down off Phenibut I like to take Magnesium, Ashwagandha, and L Theanine with a lot of water. This calms my mind and allows my body to rest easy while it repairs itself. A good session of cardio or lifting weights also helps even though you probably won’t feel like doing much. Avoid stimulants.

Conclusion

So how long does Phenibut last? Well technically 10 hours but as you can see this is not subjectively true for some people. If you count the 24 hour after glow as well as the following rebound anxiety the Phenibut experience can last for 3 days. Phenibut is considered a long lasting compound best saved for days when you’re dealing with heavy anxiety oriented tasks.