Phenibut is a drug that I’ve read about for years but never got around to trying.
My general impression of phenibut is that it’s similar to benzodiazepines in its mechanism of action – but slightly safer and less likely to cause addiction/dependence.
I’ve read about people in the “biohacking” communities using phenibut to manage stress & anxiety – particularly in social situations.
Because I wanted to try phenibut, I scoured Google and Reddit for the best phenibut vendors and buying phenibut online in 2023.
Best/Top Phenibut Source & Vendors Online (2023)
There are many highly-suspect phenibut vendors online.
Generally it is recommended to get your phenibut tested to ensure that the product actually contains phenibut & is devoid of contamination before using – especially if you’re using a relatively unknown/new vendor.
Testing can be done with sites like GetYourDrugsTested.com… better safe than sorry.
Affiliate notice: I am an affiliate for Lift Mode & Science.Bio – so will earn a commission if you buy through my link. The cost is the same either way… I’d appreciate your support.
- Lift Mode: Regarded as the top vendor for phenibut now that NootropicsDepot no longer sells it. Some people have complained that LM’s phenibut has changed over the years in quality – but none of these claims can be objectively substantiated.
- Science.Bio: Another phenibut vendor that many people claim is legitimate and reliable.
- NutriVita Shop: Sells phenibut in bulk increments of 1000 g, 5000 g, 10 kg, and 25 kg. If you want a massive amount of phenibut – this may be a place to consider.
- NextValley: Sells phenibut to European customers… not available for those in the U.S.
- Raw Powders: Sells phenibut to European customers… not available for those in the U.S.
Note: Certain phenibut vendors may be more reliable in the U.S. – and others may be more reliable in the E.U.
Chemical formats of phenibut (differences)
The chemical forms of phenibut sold online include: Phenibut FAA & Phenibut HCL.
- Phenibut FAA: This “Free Amino Acid” form is closer to a pure version of phenibut without additional molecules. Thought to have the highest bioavailability.
- Phenibut HCL: Phenibut bound to hydrochloride molecules to enhance stability and solubility. Thought to have slightly lower bioavailability than the FAA form.
Physical formats of phenibut (differences)
There are various physical formats of phenibut sold online including: powders, capsules, and crystals (large vs. fine).
- Powder (HCL & FAA): Typically cheaper and allows for precise dosing but can be difficult to handle and may taste unpleasant. Additionally, some may want to avoid the powder for fear of mis-measuring the dosing and taking too much (increasing risk of overdose).
- Capsules (HCL & FAA): Pre-measured doses of phenibut that are more convenient. Ideal for those who want to minimize risk of measuring errors and overdosing with powder formats.
- Large crystals (HCL): Large crystals of phenibut that dissolve slowly in liquids and may have a slower onset of effect.
- Fine crystals (HCL): Dissolve faster in liquids and may have a quicker onset of effect (relative to large crystals).
- Solution (HCL): May offer faster absorption and/or slightly higher purity – but this hasn’t been confirmed.
Which form of phenibut is the most bioavailable?
The bioavailability of Phenibut FAA vs. Phenibut HCL isn’t well-documented in scientific literature and information from online vendors can be inaccurate and/or biased.
Based on the respective chemical properties, it’s often suggested that Phenibut FAA might have slightly higher bioavailability due to its purer form vs. Phenibut HCL – which is bound to hydrochloride molecules (making it less potent by weight).
Which type of phenibut is the most cost-effective? (potency of dose for $)
When considering a purchase of phenibut online, most people want to get the most (in terms of dosing) for their money.
Cost-efficacy may vary significantly depending on the vendor, purity of product, and the form in which phenibut is manufactured (powder, capsules, or crystals).
Powders: Generally the cheapest due to the fact that vendors don’t need to buy capsules and/or pack the powder into capsules for users.
- Phenibut FAA: Assuming a modest bioavailability increase over Phenibut HCL, this is probably provides the most potent dosing for one’s money.
- Phenibut HCL: Comparable in cost to Phenibut FAA but may offer slightly less bang-for-your-buck than Phenibut HCL.
Crystals: Priced similarly to the powders but are in “crystalized” forms of HCL (fine vs. large crystals).
- Fine crystals: Relatively similar pricing to standard non-crystal powder. Can be used to make one’s own phenibut capsules (e.g. buy empty capsules and pack inside).
- Large crystals: Slightly more expensive than fine crystals – some may simply prefer these large crystals for convenience and/or to verify purity.
Phenibut solution: Various vendors sell phenibut solution. The one on Lift Mode is 360 mg per ml with a total volume of 30 ml. Assuming no major increase in bioavailability – it’s pricing is slightly better than powder HCL but worse than powder FAA.
Capsules: Tends to be the most expensive way to buy phenibut because the vendor already encapsulated the phenibut for you (saves time and effort). For those who want to avoid the hassle of measuring out doses – capsules are the most convenient.
Note: Anecdotally many people claim HCL is more likely to cause GI-related side effects (e.g. stomach upset, nausea, etc.) than FAA. Some claim HCL subjectively “works” better than FAA… and others claim the opposite. None of these claims can be objectively verified.
How long does Phenibut last (effect)?
The onset & duration of phenibut’s effect can vary among users based on a variety of variables.
- Onset: Typically within 2-4 hours of administration.
- Peak effect: Typically within 4-6 hours of administration but will vary based on metabolism, stomach content (empty vs. full), phenibut format, etc.
- Duration of action: Thought to last ~15-24 hours depending on dosage and metabolism.
- Half-life: Estimated at around 5.3 hours but can vary among individuals.
- Elimination time: Expected to be eliminated from the body within 24-48 hours – with some variation among users.
Phenibut usage: Things to consider…
Included below are some general recommendations for those considering prior to using phenibut.
- Confirm safety with medical doctor: Verify that phenibut is okay or safe for you to take given preexisting conditions, supplements, and/or medications that you use.
- Confirm the product contains phenibut: Verify that the product you’ve purchased actually contains phenibut and is devoid of impurities. (Sites like: GetYourDrugsTested.com work well for this). Only purchase from reliable/trustworthy vendors.
- Low dosage: Stick with a low dose of phenibut until you know how phenibut impacts your physiology. Better to play it safe than be sorry.
- Consider phenibut alternatives: There may be safer alternatives to phenibut that you can get from a medical doctor or supplement company.
- Understand the risks: No drug and/or supplement is completely devoid of risks – understand all risks (including interactions & contraindications) of using phenibut before administration.
How to take Phenibut HCL & Phenibut FAA? (Dosage & Administration)
Disclaimer: None of this should be interpreted as medical advice. Talk to a medical doctor if you’re considering phenibut to verify safety & avoid contraindications.
Phenibut HCL: Recommended starting dosage is 200-300 mg/day – according to Redditors and random nootropics enthusiasts online.
- Administered orally with water.
- Generally taken on an empty stomach to maximize effect.
- Onset of action for Phenibut HCL is ~2-4 hours.
- Duration of action for Phenibut HCL is ~15-24 hours depending on the dosage.
Phenibut FAA: Recommended starting dosage is 100-200 mg/day – according to Redditors and random nootropics enthusiasts (due to its higher potency/bioavailability than Phenibut HCL).
- Administered orally with water.
- Generally taken on an empty stomach to maximize effect.
- Sublingual administration is NOT recommended due to the acidity – which may cause mouth burns and/or tooth erosion.
- Onset of action for Phenibut FAA is 2-4 hours, peak effect reached 4-6 hours after administration, total duration of effect is ~15-24 hours depending on dosage.
From where are phenibut vendors sourcing their product?
Many vendors claim to be sourcing their phenibut in the U.S. and Europe – but most suspect that they’re sourcing from China & Russia due to the lower costs.
This isn’t necessarily a problem as long as testing is done to confirm that the phenibut being sold is legitimately pure phenibut – and not contaminated with other drugs/substances.
Contamination with other substances is a major concern – particularly fentanyl – as it only takes a small amount of fentanyl to be deadly… I’ve yet to read any confirmed report of phenibut contamination with fentanyl.
Another potential issue is dosing – some phenibut vendors may list a specific dosage on their product yet the dosage may be significantly higher or lower than the listed amount.
For this reason, you may get a product that packs significantly more or less of a physiological punch than expected.
Have people tested “Lift Mode” phenibut to verify contents?
Many people claim to have tested Lift Mode’s phenibut and can vouch for its contents… However, you can always test it for yourself if you don’t want to trust randoms on the internet.
Test 1: In February 2023 one individual tested Lift Mode phenibut to determine whether it contained fentanyl – and detected zero fentanyl in the product.
- This testing was done in response to a user alleging that they tested positive for fentanyl after using Lift Mode’s phenibut.)
- It is unclear as to whether the claim was legitimate, trolling, or made by a competitor to Lift Mode.
Test 2: Phenibut HCL (Lift Mode). FTIR spectrometer.
- Result was 90-95% phenibut in February 2023 – and 5-10% uncertain match.
- This individual was concerned because Lift Mode claims it is HPLC tested at 99% purity.
- Many claim that the phenibut itself is 99% purity but various fillers are added (explaining the 5-10% other contents in the batch) – but others retort that fillers aren’t used in Lift Mode products.
One individual claims that the numbers on Lift Mode COAs do NOT correspond in length or particular digits to the lot numbers on the actual containers – thus this person suspects that they’re obtaining samples from superior manufacturers and getting those tested while filling their containers for retail with samples from inferior (cheap) manufacturers.
Lift Mode phenibut contains gabapentin? (True or false rumor?)
Another person claimed that they tested positive for the drug gabapentin after taking Lift Mode’s phenibut – but others claimed that they were also drug tested and never tested positive for gabapentin.
Someone noted that gabapentin & phenibut are “extremely similar molecules” since they’re both ring-substituted GABA analogues – so there’s a chance phenibut could’ve triggered a false positive for gabapentin on certain drug tests (not sure whether this is legitimate).
A retort claimed that a false-positive for gabapentin from phenibut use is unlikely because gabapentin has a cyclohexane ring vs. phenibut has an aromatic benzene ring – each with drastically different chemical properties.
However, I found a scientific publication noting that “phenibut is a drug similar in structure to gabapentin and pregabalin” – so I think false positive for gabapentin on a drug test is plausible. (R)
Another individual claims to know where Lift Mode “gets their stuff” and that the supplier sells “bulk gabapentin” – so there’s a chance Lift Mode phenibut could’ve been cross-contaminated with gabapentin.
Furthermore, many claim that Lift Mode has an entire marketing team dedicated to hyping up their products on various forums – giving others the impression that it’s the best.
There are so many allegations re: Lift Mode phenibut online that I’m not really sure what to make of them… contamination with gabapentin wouldn’t necessarily bother me if true but would be concerning.
What about NootropicsDepot? (Why did they stop selling phenibut?)
Arguably the most trustworthy supplement, nootropics, and legal drug dealer online was NootropicsDepot (ND).
The primary reason they stopped selling phenibut was because the payment processor (bank, card, etc.) didn’t like them selling it – as well as all of the racetams (piracetam, aniracetam, etc.), so they stopped.
At the time many thought NootropicsDepot was subject to an FDA crackdown and legal battle, but it seems they simply wanted to minimize business risk by discontinuing the sale of phenibut, racetams, etc.
For this reason – some nootropics buyers live by the slogan “Lift Mode for everything ND doesn’t have.”
Phenibut mechanism(s) of action
Phenibut functions as a GABA-mimetic – primarily at GABA-B and to some extent GABA-A receptors. (R)
It also stimulates dopamine receptors and antagonizes B-phenethylamine (PEA) – a putative endogenous anxiogenic.
Pharmacologically, phenibut is thought to be most similar to the drug Baclofen – but many have compared it to various benzodiazepines and gabapentinoids (gabapentin & pregabalin).
- Phenibut acts similarly to GABA in several studies and produces comparable electrophysiological effects on the ion channels of neurons.
- It has been found to increase the release of GABA from presynaptic nerve endings.
- Phenibut mostly activates GABA-B receptors – as supported by multiple studies.
- Phenibut may exert a less significant secondary effect on GABA-A receptors.
- Chronic use of phenibut and discontinuation alters the density of GABA-B & GABA-A receptors in various brain regions.
- Phenibut increases dopamine levels and metabolites in animals – and may activate dopaminergic processes in humans.
- Effects of phenibut on dopamine and its metabolites can be counteracted by various drugs.
- Phenibut can be viewed as a derivative of phenethylamine (PEA).
- Phenibut counteracts anxiety-inducing effects of PEA in animal models – and may also prevent PEA-induced excitation and/or seizures.
Note: Baclofen is more potent than Phenibut in many effects but the 2 drugs are chemically similar.
Phenibut side effects (common)
There isn’t significant research on the common side effects of phenibut – but there are a lot of user reports.
Additionally, based on its mechanism of action – many side effects can be inferred.
- Sedation & drowsiness: Phenibut may induce sedation or drowsiness – particularly at high doses.
- Dizziness: This is a common side effect with many GABAergic drugs and has been reported by phenibut users.
- Cognitive impairment: May include memory issues, decreased attention span, and mental slowing.
- Motor impairment: Some may notice impaired motor skills while using phenibut – similar to benzodiazepines. Nobody should be operating heavy machinery or motor vehicles on phenibut.
- Muscle relaxation or weakness: GABAergic drugs can increase muscle relaxation – which may be perceived as weakness.
- Mood changes: Some report changes in mood on phenibut including: euphoria (possibly due to dopamine alterations) & depression (possibly due to GABAergic effect/sedation).
- Nausea & upset stomach: Phenibut may cause upset stomach, gastrointestinal distress, and related side effects.
Phenibut dangers, adverse reactions, overdose/toxicity
Over 1,300 calls to U.S. poison control centers involved phenibut ingestions. (R)
Common adverse reactions were lethargy, agitation, tachycardia, and confusion.
A literature review in 2023 reported 62 cases of phenibut toxicity – with an average hospital stay of 5 days. (R)
The most common symptoms of phenibut toxicity include: altered mental status, somnolence, psychosis, and movement disorders.
Intubation, respiratory depression, coma, and death have been reported in phenibut overdose/toxicity and/or when combined with other CNS depressants (e.g. alcohol, benzodiazepines, opioids).
Is phenibut legal to purchase in the United States? (2023)
- As of 2023 – phenibut is legal to purchase and possess in the U.S. without a prescription – however, some states are considering regulation and/or bans.
- Phenibut is NOT approved for any medical uses in the U.S. – it is regarded as a dietary supplement.
- In 2019, the FDA issued a warning about phenibut – cautioning consumers about its risks and potential for addiction/dependence. The FDA advised against using it.
- Phenibut cannot be marketed as a dietary supplement with claims that it can cure, treat, or prevent any disease or health condition. Marketers cannot claim it is safe or effective for human consumption.
- Some online retailers and supplement companies have voluntarily stopped selling phenibut due to concerns over its addictive properties, future changes in legal status, and potential lawsuits.
- The DEA has not yet (September 2023) federally scheduled or controlled phenibut as an illicit substance at this time – but it continues to monitor concerns over its abuse potential.
What does the FDA think about phenibut?
Between 2017-2019 it was reported that the FDA issued warning letters to companies selling phenibut supplements or including phenibut as a component of various supplements.
However, a research team led by Dr. Pieter Cohen (Harvard Medical School) reported that many companies did NOT receive warning letters and thus continued selling phenibut. (R)
Interestingly, researchers tested the remaining phenibut supplements from vendors and found that not only was the phenibut content significant – it had actually increased in potency.
According to an attorney – the FDA is a law enforcement agency but warning letters have no deterrent effect on sales because there are no consequences.
Technically the FDA could crack down on vendors with legal consequences – but they’re not.
FDA statement: “The FDA is dedicated to advancing our strategic priorities for dietary supplements: safety, product integrity, and informed decision-making.”
Phenibut withdrawal symptoms…
These will generally depend upon: (1) frequency/duration of administration (e.g. daily for years vs. once a week for a month); (2) dosage & tolerance; (3) rate of discontinuation (cold turkey vs. tapering); (4) use of other substances (during withdrawal); and (5) the specific user.
A systematic review by Weleff et al. (2023) noted that ~95.7% of those with phenibut withdrawal symptoms reported “daily use” of phenibut. (R)
The most common withdrawal symptoms were: anxiety, irritability & agitation, insomnia, and psychosis.
- Anxiety: Increased anxiety levels are common after stopping phenibut – especially for persons who use high doses and/or have an underlying anxiety condition.
- Insomnia: Many people have difficulty falling asleep and/or staying asleep due to the increase in excitatory neurotransmission & sympathetic nervous system activation in withdrawal.
- Agitation & irritability: Individuals may be agitated and/or irritable for several days after stopping use.
- Appetite changes: Changes in appetite have been reported upon discontinuing phenibut – such as appetite reductions from higher stress.
- Cognitive deficits: Brain fog, difficulty concentrating, etc. may occur as the brain readjusts to normalcy without the influence of phenibut.
- Fatigue: Physical and mental fatigue/lethargy have been reported during withdrawal.
- Psychosis: A serious reaction that has been reported in phenibut toxicity and withdrawal is psychosis – or an altered mental state characterized by a disconnection with reality that may be accompanied by delusions and/or hallucinations.
- Restlessness: Due to a combination of anxiety and agitation in withdrawal, some individuals have reported experiencing significant restlessness after stopping phenibut.
Note: Gradually tapering off phenibut, working with a medical doctor, and/or using other medications and/or supplements might make withdrawal easier to manage in some cases.
Why do people use phenibut in the first place?
Hansen et al. (2023) investigated the reasons people use phenibut. (R)
- Recreation: To experience altered states of consciousness, pleasurable effects, and/or as a social lubricant (making social situations less stressful).
- Benzo substitution: Those who derive benefit from benzodiazepines but are unable to get a prescription may turn to phenibut as an alternative. Some also think that phenibut is safer than benzos.
- Psychiatric treatment: Some have used phenibut to manage a psychiatric condition like anxiety disorders, insomnia, OCD, PTSD, and/or depression.
- Withdrawal from other substances: Some individuals use phenibut to help counteract withdrawal symptoms from substances like alcohol, opioids, and benzodiazepines.
- Performance enhancement: Some claim that phenibut enhances work and/or social performance – so they use it “as needed” for this purpose.
Have you purchased phenibut online?
Which vendor do you think offers the highest-quality phenibut for your money?
Have you noticed any change in the effect of phenibut from various vendors over time?
Do you think certain vendors have contaminated phenibut or are providing misleading COAs & third-party tests?
Do you prefer Phenibut HCL vs. Phenibut FAA – or do you think they’re both too similar to have a preference?