Phenibut HCL vs. FAA: Differences & What's Better

Updated on August 1, 2023
 by — reviewed by Jason Williams, PhD (Contributor: George Collins / Editor: Yoko Hill)

If you are curious about Phenibut HCL and FAA, this post will tell you about their properties and which administration or form can fit you.

You must be familiar with L-Theanine, the mild nootropic supplement that promises its users better mood, alleviated stress, and reduced anxiety levels.

Along with it, Phenibut is also one of the anti-anxiety nootropic supplements that carry the same or even yet, better effects.

Both nootropics are a white powder that works on the brain GABA receptors and improves mood, but their similarities end there.

We won’t be discussing L-Theanine vs. Phenibut. Instead, we will be pitting the two forms of the latter: Phenibut FAA vs. Phenibut HCL.

One other form of Phenibut is the F-Phenibut. It has a behavioral potency approximately five to tenfold higher than Phenibut, but we will be covering the two most common supplements.

phenibut hcl vs faa featured image

Read on as we help you save time to find out which Phenibut suits you.

What is Phenibut?

β-Phenyl-γ-aminobutyric acid (also known as Phenibut) is a drug that was first introduced in the Soviet Union in the 1960s. It is a nootropic compound of the gabapentinoid class that acts as a receptor that binds with GABA.

phenibut structure

Phenibut is a nootropic drug with GABA-B agonist and α2δ subunit-containing voltage-dependent Ca2+ channel blocker activity with neuroprotective and anxiolytic properties.

With this, Phenibut is regarded as a treatment for anxiety, post-traumatic stress disorder, depression, insomnia, alcohol withdrawal syndrome, stuttering, and vestibular disorders. Russian astronauts even used it for their space program.

Despite these benefits, Phenibut is still not sanctioned as treatment outside of the global east, but it has been a known nutritional supplement that allows us to reap many benefits.

As previously mentioned, Phenibut FAA and Phenibut HCL are two of its forms with not much varying effectiveness and usage.

Benefits, Safety, and Side Effects

Phenibut is a nootropic substance with a structure similar to neurotransmitter y-aminobutyric acid (GABA). It works as any depressant would do to your central nervous system but also providing that stimulant effect.

benefits safety side effects phenibut

The benefits include the following.

  • Reduced stress and anxiety by enhancing blood flow and normalizing your neurons
  • Much less social anxiety
  • Restore sleep pattern
  • Cognitive enhancements and better focus because of the simultaneous stimulation of GABA and dopamine receptors
  • Less “brain fog” due to improved inter-hemispheric transmission in the brain
  • Used to boost mood
  • Feelings of euphoria
  • Creativity because of reduced neuronal activity allowing ideas to flow freely.

Doctors in several countries also reported the following benefits of using Phenibut.

  • Used to alleviate alcohol cravings
  • Reduce risks of chronic stress and abnormal heart rhythm
  • Reduced fatigue
  • Can be taken as an anxiolytic to treat anxiety
  • Help recover after a workout
  • Manage insomnia
  • Experience greater control over feelings and thoughts
  • Managing symptoms of depression and post-traumatic stress disorder (PTSD)
  • Pleasurable sexual experience because of stimulation to the pleasure receptors

The majority of users who do use Phenibut do not report any issues. As rare as it can be, there are still incidents of abusive use of Phenibut.

Due to Phenibut’s long shelf-life, it can stay on your system for a long time.

Since Phenibut and alcohol work in similar ways in blocking the brain’s GABA receptors, taking it beyond the recommended dosage can amplify sedatives’ effects and other hypnotic substances and medications.

Similar to when taking too many sedatives, the possible side effects of Phenibut include:

  • Drowsiness
  • Nausea
  • Irritability
  • Headache
  • Sedation

Even more rare symptoms include motor incoordination, effects similar to a hangover, and loss of balance.

Withdrawal symptoms can also occur, like rebound anxiety, anger, agitation, auditory and visual hallucinations, and psychosis.

To avoid these, here are the recommended guidelines on how to use Phenibut effectively.

  • Start from a small dose and work your way up while checking its effect on your body.
  • Don’t take it if you think you are allergic.
  • The single-dose limit of Phenibut is 1 g.
  • The per-day limit of Phenibut is 2 g.
  • Don’t use more than 2 to 3 times a week.
  • Don’t use it with other depressants like alcohol, benzodiazepines, or anticonvulsants.
  • Don’t use it if you’re pregnant, breastfeeding, have issues with your liver or stomach, or have an addiction tendency.

One of the most important things to keep in mind, especially if you are new to taking Phenibut, is to take a few days to break from it once in a while.

Since it stays on our system for a long time, it is easy to lose track of its effects on our bodies.

Phenibut HCL

Among the three forms of Phenibut, the most common in the market is the HCL version. It comes in the hydrochloride salt form, which is generated by having the free amino acid react against hydrochloric acid.

Phenibut HCL is a zwitterionic HCL salt. This means its composition is in the form of a “dipolar ion.” With this, the HCL version of Phenibut has both a positive and negative ionic electrical charge, partially explaining why it holds such unique nootropic properties.

How to Take Phenibut HCL?

Since Phenibut HCL is a zwitterionic substance, it exists in a very stable and easily dissolvable hydrochloride salt form. When using Phenibut HCL, users must dissolve the salt in a glass of water. It also exists in more convenient forms, like capsule form. It is best used at least an hour after a meal or on an empty stomach.

how to take phenibut hcl

Aside from water, HCL Phenibut can also be dissolved in a citrus juice or energy drink. You can also have the option to use warm water to dissolve it better.

Some may find a mildly bitter taste. But washing it down with another acidic beverage like citrus juice can help neutralize the lingering aftertaste entirely.

When you take Phenibut HCL capsules or salt form, it is not advisable to use sublingual administration or dissolve it under the tongue as Phenibut HCL is very acidic. It will taste really bad, will irritate your mucous membrane, and will very much damage your tooth enamel.

A light dose of Phenibut HCL is 250 – 750 mg. This lower dosage produces a mild mood increase and a feeling of calmness.

A medium dose is between 750 and 1500mg. You will still get a mild mood increase and calmness, but along with it is increased sociability. At this dosage of Phenibut HCL, it will get you better sleep throughout the night.

It is highly recommended not to go over between the high dosage of 1500 and 2000 mg of Phenibut HCL powder on any given day. This can cause low heart rate, low breathing rate, dizziness, and sweating.

Phenibut FAA

Another form of Phenibut is a free amino acid (FAA) or commonly known as Phenibut F. A.A. With its suitability for sublingual administration, it becomes a close option aside from its hydrochloride salt counterpart.

Unlike the Phenibut HCL form, the Phenibut FAA nootropics do not have a dipolar ion charge.

Phenibut F AA is a fine white powder and is less dense than the crystalline Phenibut HCL form. When it comes to purity Phenibut HCL vs. FAA, the latter is most pure with approximately 99.5% Phenibut molecules by weight.

When consumed in the usual way, the Phenibut FAA form is about 15% more efficient than Phenibut HCL, but significant FAA‘s density advantages are yet to be decided.

The most common dosage for Phenibut F AA is between 500 and 1250 mg.

How to Take Phenibut FAA?

Since Phenibut FAA is a powdery substance that is not highly soluble, it is more likely just to break apart or not fully dissolve in water. Thus, it is not recommended to take Phenibut FAA in the form of capsules.

how to take phenibut faa

The recommendation of F AA is sublingual administration. At least one hour after a meal or on an empty stomach, take Phenibut FAA under the tongue, where it dissolves and enters the bloodstream directly.

The method may be fast-acting, but the bitter taste because of its purity will turn most people off.

Some would try to dissolve FAA in a drink instead of sublingual administration, but it is not ideal because it is not easily dissolved in water. Others will put it into dissolvable paper and swallow it.

Which is Better?

Although the free amino acid form Phenibut is the same nootropics as Phenibut HCL at the molecular level, the latter is more affordable and user-friendly.

Phenibut FAA, available in sublingual form, will take several minutes to be absorbed in the bloodstream and will leave a lingering bitter taste under the tongue for hours.

While Phenibut F AA is highly pure with more than 99.5% Phenibut molecules by weight, Phenibut HCL, even when completely pure, is only approximately 83% Phenibut molecules by weight, the other 17% being HCL.

Some will tout F AA’s density by weight, saying that it is 15% more efficient than Phenibut HCL when it has nothing to do with administering an effective dose at a reasonable price.

When it comes to Phenibut HCL vs. Phenibut F AA, the general verdict would be the Phenibut HCL.

People will most likely buy Phenibut in the hydrochloric acid form, mostly because it is more convenient, and it is a lot cheaper, allowing more people easier access to Phenibut’s benefits.

Phenibut HCL vs. FAA, which is your choice?


Deciding on which form of Phenibut is best would boil down to how convenient Phenibut FAA vs. HCL is for the consumer. May it be in liquid or capsule form, it is a matter of the user’s preference.

Although the free amino acid form is taken under the tongue, Phenibut HCL can be quickly consumed with a swish of water.

When you buy Phenibut, whichever nootropics you choose between Phenibut HCL vs. Phenibut F AA, the best option is to buy it from a legit online website. There are a lot of good options online. You can check website reviews and get more acquainted with the product, whichever brand you choose.