While Phenibut and GABA are different supplements, they are very closely related to one another. These two supplements are both used for effects that range from cognitive enhancement to stress reduction and even to relaxation. In fact, anyone who is looking to help improve or balance out their moods, or even improve their effectiveness in the gym might want to seriously consider these supplements. Of course, this raises the ultimate question: Which of these supplements is better?
GABA, or Gamma-Aminobutyric Acid, is an amino acid which is produced within the brain from glutamate and vitamin B6. While GABA is consideredan amino acid, it is not found in the proteins of the food you eat or in your own body’s store. Almost all of the GABA in your body must be synthesized from stored glutamate. 
This supplement is also a neurotransmitter, a powerful brain chemical. In fact, it is the chief inhibitory neurotransmitter within the body that allows for balancing out other chemicals and processes that may cause neuron over excitability. When your body lacks GABA, chances are the neurons in your brain will fire off too quickly which contrary to how it sounds, will keep you from focusing, cause anxiety, and worsen depression.
The primary benefit of GABA is to help balance out normal moods. Additionally, it helps to directly regulate muscle tone throughout the body and even supports the production of hormones that are needed to build muscle. GABA also helps neurons within the brain communicate more efficiently with each other. It is also reported to help with mental clarity, attention, and focus. 
What is Phenibut?
Phenibut is essentially a derived formulation of GABA. It is GABA plus a phenyl group molecule ring. The reason for this addition is that it helps the supplement to cross over the blood-brain barrier. The main problem with pure GABA is the fact that it is much more difficult for it to cross over this barrier and actually enter into the central nervous system. 
Once Phenibut gets into the nervous system, it has many of the same effects as GABA. Thus, Phenibut helps to calm the mind and leads to relaxation, reduction of stress, and a balancing of moods. It has also been shown to increase the body’s levels of dopamine. 
The main draw of phenibut is its potency. The fact that it absorbs better than pure GABA means that the effects are much stronger and take significantly less time to notice. 
It is also worth noting that phenibut is a little more versatile in its uses than ordinary GABA boosters. In fact, many body builders and weight lifters use Phenibut powder as a pre-workout supplement because it helps them to maintain mental clarity and enhances concentration and focus during their workouts. 
GABA Side Effects
Both supplements do have possible side effects that can usually be avoided with proper usage. However, if you’re worried about possible complications, here is a side-by-side comparison to help you determine if either one has a negative effect that could be a deal breaker.
When it comes to GABA, there are a few things to keep in mind. Always keep to the recommended dose, for one. While not guaranteed, some reports have shown that high dosages can lead to skin flushing or tingling. 
More importantly however would be to avoid GABA if you suffer from serious depression. GABA is mainly used to calm down heavy anxiety, but may trigger an episode in those suffering from severe forms of depression. If you suffer from this type of depression, a serotonin booster may be more useful than a GABA booster. 
Phenibut Side Effects
Along with the side effects that a GABA booster may present, phenibut has been reported to be somewhat habit forming and can cause withdrawal symptoms in heavy users. This can include “nervousness and shakiness, psychomotor agitation, feeling easily annoyed and irritated, fatigue, anxiety, poor appetite, heart palpitations, nausea, insomnia, and feeling tense and keyed up” 
These effects can usually be avoided by taking a recommended dose or lower and not using it more than a few times a week at most. If you do experience these side effects they are usually reported as lasting 5-7 days. 
Conclusion—Phenibut or GABA?
So which supplement is better? Phenibut is certainly much more powerful and also faster acting. Since this supplement is better able to cross over the blood-brain barrier, this could be a very important factor. However, the possible side effects of misuse are also a little steeper.
In contrast, GABA is less potent and should probably be taken with other supplements to ensure that it has a ‘carrier’ in order to enable it to enter into the central nervous system.
There is no one best answer to this question, as there are numerous factors at play here and what works for some will not necessarily work for all. As long as you stick to recommended dosages and use caution, either supplement is a perfectly viable option. However, for combating pure anxiety, phenibut comes out ahead for its potency and versatility.