What are caffeine and L-theanine?

Caffeine is a central stimulant. L-theanine is an amino acid from tea that promotes calm alertness. Together they can support attention and task accuracy with fewer jitters than caffeine alone.

Why stack caffeine with L-theanine?

The pairing balances stimulation with smoothness. Studies report improvements in attention, reaction time and accuracy compared with caffeine alone.

What’s a common starting dose?

A frequently used starting ratio is 100 mg caffeine with 200 mg L-theanine. Adjust based on sensitivity and total daily caffeine intake.

Are there side effects or interactions?

Caffeine may cause jitters or sleep disruption. Avoid late dosing. Check medications and health conditions with a professional. L-theanine is generally well-tolerated.

Understanding Phenibut (β‑Phenyl‑GABA): Mechanism, Benefits, Risks, Dosage & Legal Status in 2025

March 13, 2024 3 min read

A clear, current guide to Phenibut: how it works, potential benefits for anxiety and sleep, real risks (tolerance, dependence, withdrawal), and the 2025 legal status in the U.S., Australia, and EU—plus responsible‑use tips and Nootropix product options.

Quick take: Phenibut is a GABA‑B–acting compound that may ease anxiety and improve sleep when used sparingly, but it carries real risks of tolerance, dependence, and difficult withdrawal—so informed, cautious use matters. [Ref 1, 2]

What is Phenibut?

Phenibut (β‑phenyl‑γ‑aminobutyric acid) is a synthetic analogue of GABA developed in the former Soviet Union.

The added phenyl ring helps it cross the blood–brain barrier, where it primarily modulates inhibitory signaling and dampens nervous system over‑arousal. [Ref]

Historical context

First synthesized in the 1960s and introduced clinically in the 1970s, Phenibut was explored for stress resilience, sleep, and situational anxiety. [Ref]

Mechanism of action

Primary action — GABA‑B agonism: Produces a calming, anxiolytic effect. [Ref 1, 2]
Additional target — α₂‑δ subunit (calcium channels): May contribute to anxiolytic/analgesic effects, similar to gabapentinoids. [Ref]
Monoamine modulation: Animal data show changes in dopamine metabolites (e.g., elevated DOPAC in striatum), suggesting subtle mood/motivation effects. [Ref]

Takeaway: GABA‑B activity is the core. Reports of direct GABA‑A involvement are mixed; they are not considered the primary mechanism. [Ref]

Potential benefits

Phenibut benefits at a glance infographic

Anxiety reduction

Via GABA‑B agonism, Phenibut can reduce somatic tension and social unease for some users. [Ref]

Improved sleep quality

Many report easier sleep onset and deeper sleep after stressful periods; mechanistically this aligns with reduced excitability through GABA‑B signaling. [Ref]

Risks & side effects

Common effects

Drowsiness, dizziness, nausea, headache, slowed reaction time.

Tolerance, dependence & withdrawal

Frequent/long‑term use can lead to tolerance, dependence, and a difficult withdrawal (anxiety, insomnia, agitation; severe cases can involve delirium or seizures). [Ref 1, 2]

Overdose

High doses raise risk of profound sedation, respiratory depression, coma; seek urgent care if suspected.

Dangerous combinations

Alcohol or other CNS depressants: Do not combine—additive respiratory/CNS depression can be life‑threatening.

Legal status (updated for 2025)

United States (federal): Not an approved dietary ingredient; supplements listing phenibut are considered misbranded. Not scheduled federally. [Ref 1, 2]
Alabama (USA): State‑controlled (Schedule II) since Nov 14, 2021. [Ref]
Utah (USA): Added to Schedule I in 2025 (HB0173; signed Mar 25, 2025). [Ref]
Australia: Schedule 9 (prohibited substance) since Feb 2018. [Ref]
EU examples: Controlled in France, Italy, Lithuania, Hungary; other member states vary. [Ref]

Note: Laws change quickly; always confirm local regulations before purchase or use.

How to use responsibly (not medical advice)

Limit to occasional use (e.g., 1–2 times/week) to reduce tolerance/dependence risk.
Start low; avoid same‑day redosing.
Never combine with alcohol, benzodiazepines, opioids, or sedatives.
Do not drive or operate machinery after taking Phenibut.
If discontinuing after regular use, taper under medical supervision. [Ref]

Phenibut FAQ

What’s a typical dose?

Many start around 250–500 mg; experienced users may use 500–750 mg. Higher doses increase adverse effects—more is not better.

How long do effects last?

Onset ~1–2 hours; effects can persist for many hours and occasionally into the next day.

Is Phenibut addictive?

Frequent use can be habit‑forming; withdrawal can be significant. [Ref 1, 2]

How does it compare to benzodiazepines?

Different receptors (GABA‑B vs. GABA‑A). Both can cause sedation; both are risky with other depressants. Avoid mixing.

Can I stack it?

Avoid stacking with anything sedating; do not combine with alcohol, benzos, opioids, or sleep meds.

Related nootropics (calmer, daily‑friendly options)

L‑Theanine 200 mg capsules: Calming without drowsiness; pairs well with caffeine.
GABA 500 mg capsules: Gentle relaxation and bedtime support for some users.
Ashwagandha KSM‑66: Adaptogenic support for stress and sleep quality.

Shop Phenibut formats

Resources

NIH PubChem — Phenibut (compound entry): [Ref]

Medical disclaimer: This article is informational and not medical advice. Speak with a qualified clinician before using Phenibut, especially if you have health conditions or take medications.