Alcohol

Alcohol
Formula	C₂H₆O
Type	Ethanol; small alcohol molecule; CNS depressant (GABA-A potentiator, NMDA antagonist)
Administration	Oral (drinking)
Solubility	Fully miscible with water
Legal status	Legal, age-restricted in most countries; taxed and regulated
Synonyms	Ethanol, ethyl alcohol, booze, liquor
Bioavailability	Oral: ~80-100% (first-pass metabolism in liver and stomach reduces this somewhat)
Recommended dose
Upper limit
LD50
Ray's verdict	Depends on context Alcohol cravings often track hypothyroidism and high serotonin, not a primary addiction

Alcohol (ethanol) is a small, water-miscible molecule and the active ingredient in beer, wine, and spirits. It acts as a central nervous system depressant, primarily by potentiating GABA-A receptor activity and inhibiting NMDA glutamate receptors, and is metabolized mainly in the liver via alcohol dehydrogenase and aldehyde dehydrogenase.

Have you ever had a thyroid test or tried a thyroid supplement? High serotonin activity is often present in hypothyroidism, and alcohol can probably provide temporary compensation for that.

— Ray Peat

Liver damage beyond endotoxin

Alcohol raises circulating iron and promotes cerebral iron deposition; thiamine deficiency weakens the blood-brain barrier and may allow iron entry, linking Wernicke-Korsakoff pathology to B1 repletion. Chronic binge drinking depletes hepatic NAD+ by shifting the NAD+/NADH ratio toward NADH, shutting down NAD-dependent enzymatic activities and promoting alcoholic fatty liver disease. Beyond increased intestinal LPS absorption, alcohol raises hepatocyte glutamate release via VGLUT3; glutamate stimulates Kupffer-cell mGluR5 and NOX2, producing inflammatory liver injury independent of thromboxane pathways.

Glycine protection

In rats given ethanol for 30 days, co-administered glycine (0.6 g/kg daily) reduced liver hydroxyproline and total collagen accumulation, cross-linked fibrosis markers, and lipid peroxidation, and improved collagen solubility relative to alcohol alone. This is an animal study; see Glycine.

Saturated fat protection

In rats fed alcohol for weeks alongside a diet high in saturated (medium-chain) fat, researchers were unable to induce the fatty liver, inflammation, and necrosis typically caused by alcohol; the same alcohol dose paired with a diet high in polyunsaturated corn oil instead produced severe liver injury including fibrosis. In the absence of polyunsaturated fat, alcohol doesn't produce cirrhosis. A diet enriched in saturated fatty acids reverses alcohol-induced necrosis, inflammation, and fibrosis already established in animals. A later trial confirmed this: switching rats to a saturated-fat diet after alcoholic liver injury was already present reversed the inflammation and fibrosis despite continued alcohol dosing, an effect linked to decreased lipid peroxidation. See Saturated fat, Polyunsaturated fats.

Withdrawal

Stopping heavy alcohol use can cause tremor, seizures, delirium tremens, and death in dependent drinkers; medical supervision is required for withdrawal in anyone with heavy or long-term use. No specific Peat commentary naming alcohol withdrawal exists, but his general framework for drug withdrawal (see SSRIs for the fuller tapering discussion) treats GABA/glutamate balance and progesterone/pregnenolone support as the relevant levers across withdrawal syndromes. He grouped withdrawal from morphine, SSRIs, and migraine as involving similar underlying processes, consistent with alcohol (also a GABA-A modulator like benzodiazepines) producing a comparable rebound excitotoxic state when stopped. This is not a substitute for medical detox care; seizure risk in alcohol withdrawal is real and can be fatal without supervision. See Seizure, Addiction, Epilepsy, Harm reduction.

Pregnenolone and craving

Alcohol itself raises pregnenolone and DHEA at lower doses and allopregnanolone and progesterone at higher doses; in one human study, the alcohol-induced rise in pregnenolone correlated with alcohol liking in men, and the rise in allopregnanolone correlated with both liking and desire for more alcohol. Acute intoxication raises serum allopregnanolone in both male and female adolescents relative to sober controls arriving for unrelated trauma, consistent with allopregnanolone's role as a GABA-A positive modulator contributing to alcohol's anxiolytic and rewarding effects.

Supplemental pregnenolone reduces operant alcohol self-administration dose-dependently in alcohol-preferring rats without impairing locomotor activity, and raises cortical allopregnanolone in animals with a drinking history. In humans with alcohol use disorder, pregnenolone (300 or 500 mg/day) reduced stress- and alcohol-cue-provoked craving and normalized the cortisol/ACTH ratio relative to placebo, supporting further study as a treatment.

Anecdotally, as relayed by Master Metabolism (@lowmegatron) and not from a primary transcript, an alcoholic man given pregnenolone described its effect as "the feeling I've been trying to get from alcohol, but it never worked," with his anxiety and depression lifting shortly after a 100 mg dose. See Pregnenolone.

Allergen/antioxidant effect

Ray Peat described an anecdote of tolerating foods that would normally trigger an intense allergic reaction when alcohol (including tequila and rum) was consumed alongside them, attributing this to alcohol's antioxidant effect, which he considered comparable to vitamin E's in some situations. Separately, in mice, acute and chronic binge-level alcohol (1.5 g/kg) suppressed glymphatic clearance of brain waste, an effect that reversed within 24 hours of stopping chronic moderate dosing, while low-dose alcohol (0.5 g/kg) increased glymphatic function both acutely and after a month of chronic exposure.

Reward deprivation and alcohol seeking

Sexual rejection increased voluntary alcohol consumption roughly fourfold in male fruit flies compared to sexually satiated males; the effect traced to reduced neuropeptide F (NPF, the fly homolog of mammalian reward-signaling neuropeptide Y) in deprived flies, and directly manipulating NPF signaling was sufficient to reproduce or block the alcohol-preference shift, tying it to reward-system state rather than the rejection experience itself.

Histamine and craving

Rats bred for strong alcohol preference have elevated brain histamine and its metabolites, along with a higher density of histaminergic nerve fibers, than rats with low alcohol preference. Compounds that activate the histaminergic system generally reduce the reinforcing effects of alcohol and opioids in animal models of addiction, the opposite direction from what elevated baseline histamine in high-preference rats would suggest, an unresolved tension in the histamine/craving literature rather than a settled mechanism. Estrogen raises histamine, and high gonadal estrogen during the menstrual cycle is proposed to facilitate drug-seeking in women, one contributor among several to women's greater vulnerability to addiction. See Histamine, Estrogen.

Calcium and vitamin D

In a single-blind randomized trial of 55 alcohol-dependent adults undergoing 14 days of inpatient withdrawal treatment, daily calcium carbonate (800 mg) plus vitamin D (5 mcg, 200 IU) attenuated withdrawal severity (CIWA-Ar score) faster than a sodium bicarbonate control and produced a significantly larger drop in alcohol craving, measured with the Obsessive Compulsive Drinking Scale (OCDS). The OCDS measures obsessive thoughts about drinking and compulsive drinking behavior; despite the name, it is not a diagnostic tool for obsessive-compulsive disorder. The trial's authors linked the effect to calcium's proposed role as the active component of the anti-craving drug acamprosate. See Calcium, Vitamin D.