The Sinclair Method: what the evidence says

TLDR

• The Sinclair Method (TSM) is a way of prescribing naltrexone for alcohol use disorder: 50 mg taken about one hour before drinking, instead of a daily dose. You keep drinking during treatment, and the medication gradually weakens the link between alcohol and reward.
• Naltrexone itself has strong evidence. Meta-analyses find numbers needed to treat in the range of 12 to 20 to prevent return to drinking outcomes, and the VA/DoD guideline rates it "strong for" alcohol use disorder.⁴⁵
• The 78 percent success figure that circulates online comes from Sinclair's original cohort work and has not been reproduced at that magnitude in independent trials. Treat it as a best-case clinic figure, not a guaranteed outcome.
• Any prescriber comfortable with naltrexone can prescribe it this way. You do not need a specialty clinic, and you do not need to stop drinking first.
• Naltrexone must not be combined with opioids, and people drinking at levels that risk withdrawal seizures need clinician-led withdrawal planning before reducing fast. Both situations need medical guidance.

The Sinclair Method may be the most searched-for alcohol treatment that most doctors were never taught. The questions people bring to it are practical: does it work, how do I get it, and is the famous success number real. This article answers those questions from the published evidence.

What the Sinclair Method is

The Sinclair Method, often shortened to TSM, is a specific protocol for using naltrexone, an opioid-receptor blocker that has been FDA-approved for alcohol use disorder since 1994. The defining feature is targeted dosing: naltrexone 50 mg taken approximately 60 minutes before drinking, rather than every day.¹

Two things follow from that design that surprise people used to abstinence-first treatment:

1. You keep drinking during treatment. The protocol depends on it. The medication has to be paired with actual drinking episodes for the learning process to change.
2. You take the pill only on drinking days. On days you do not drink, you do not take naltrexone.

TSM is a dosing schedule rather than a branded product or program. Any prescriber who is comfortable prescribing naltrexone can prescribe it this way, including primary care clinicians and telehealth platforms that treat alcohol use disorder.¹

How pharmacological extinction works

Research shows that alcohol stimulates the release of endorphins, the body's own opioid molecules, which bind to opioid receptors and reinforce the drinking that produced them. Over years, that reinforcement loop strengthens. Craving is the felt edge of a well-trained circuit.

Naltrexone blocks those opioid receptors. When a person takes naltrexone an hour before drinking, the alcohol still produces its other effects, but the endorphin-to-receptor reinforcement step is blocked. The drink no longer delivers the expected reward signal.

The theory behind TSM, called pharmacological extinction, is that repeating this pairing weakens the learned association the same way any conditioned behavior fades when its reward stops arriving.¹ One clinical rationale for targeted rather than daily dosing is that the blockade is concentrated exactly where the learning happens, on drinking occasions, while leaving the reward system unblocked for everything else in life: exercise, food, social connection.

This is a gradual mechanism. People on TSM typically describe drinking that becomes less interesting over weeks and months rather than a switch that flips.

What the evidence actually says

It helps to separate three layers of evidence, because they are often blurred together in TSM coverage.

Layer one: naltrexone works for alcohol use disorder. This is established by comparative research and is not controversial. A Cochrane review of opioid antagonists found naltrexone reduced the risk of heavy drinking to roughly 83 percent of the placebo group's risk and cut drinking days.³ The Jonas 2014 JAMA meta-analysis found oral naltrexone 50 mg produced numbers needed to treat in the range of 12 to 20 to prevent return-to-drinking outcomes.⁴ The 2021 VA/DoD clinical practice guideline rates naltrexone "strong for" alcohol use disorder.⁵ An NNT of 12 to 20 is comparable to or better than many widely accepted medications in general medicine.

Layer two: targeted dosing is a reasonable way to use it. The targeted approach was tested in Finnish clinical research, including a randomized trial by Heinälä and colleagues, which found targeted naltrexone without prior detoxification reduced heavy drinking when paired with coping-skills support.² Sinclair's 2001 review pulled together the trial evidence and the extinction rationale.¹ A notable detail in that literature: naltrexone performed well when paired with therapy that accepted continued drinking during treatment, and showed little benefit when paired with therapy demanding immediate abstinence. The protocol and the goal have to match.

Layer three: the famous success number. TSM advocacy materials widely cite a 78 percent long-term success rate. That figure traces to Sinclair's original cohort data from Finnish clinical work, where success was defined as regaining control over drinking, which included both reduced drinking and abstinence. It is a real number from real cohorts, and it deserves the caveat that no independent randomized trial has reproduced an effect of that magnitude for targeted dosing.¹³⁴ The defensible expectation sits in layer one: meaningful, measurable reductions in heavy drinking for a substantial minority of people who try the medication, with some achieving full extinction of craving.

If a clinic or website leads with the 78 percent figure and skips the caveat, read that as a marketing choice.

TSM versus daily naltrexone

Standard prescribing is naltrexone 50 mg daily, usually with a goal of abstinence or reduction. TSM differs in three ways:

• Timing. Dose one hour before drinking, matched to the occasion rather than the calendar. Oral naltrexone reaches peak blood levels at roughly the one hour mark, which is the reason for the rule.¹
• Behavioral frame. Drinking during treatment is expected, and each medicated drinking episode is doing the therapeutic work of extinction rather than counting as a failure.
• Duration. TSM is typically a months-long process. Three to six months is a common window for noticeable change, and many people continue using the medication before any future drinking indefinitely.

Clinicians often note that adherence is the method's main vulnerability. The protocol only works if the pill comes before every drinking occasion, without exceptions, and a person who skips the dose to feel the full effect of a drink is actively re-training the loop the medication was weakening. Honest self-assessment about whether you can hold that rule is part of deciding whether TSM fits.

The clinical bottom line: the evidence supports naltrexone strongly, and targeted dosing is a legitimate, trial-tested way to prescribe it. The two non-negotiable safety screens are opioid use, because naltrexone will precipitate withdrawal in anyone physically dependent on opioids, and liver function, which should be checked before starting.⁵⁶

The practical move is to treat the first month as a tracked experiment. Log every drinking day, the dose time, drinks consumed, and a one-to-ten craving score. Most people cannot feel week-to-week change, but a simple log makes a real trend visible by week six, and that data is exactly what your prescriber needs at follow-up.

Together, those two perspectives are the method in miniature: a medication with real evidence, run as a structured experiment with medical guardrails.

Safety: who should not start TSM without more help

• Anyone using opioids. Naltrexone blocks opioids and will trigger immediate, severe withdrawal in someone physically dependent on them. That includes prescribed opioids, methadone, and buprenorphine. This combination needs specialist guidance, full stop.⁶
• People with significant liver disease. Naltrexone is processed by the liver. Baseline liver enzymes are recommended before starting, with follow-up testing after initiation. Severe hepatic impairment is a relative contraindication.⁶
• People drinking at levels where sudden reduction is dangerous. TSM itself does not require stopping, which makes it safer on this front than quit-day approaches. But if your body is dependent enough that a low-alcohol day brings shaking, sweating, or hallucinations, you need clinician-led withdrawal management as a separate medical question. Our guide to supervised ambulatory alcohol withdrawal covers what that looks like.
• Pregnancy calls for individualized specialist advice.

Common side effects, mostly in the first one to two weeks, include nausea, headache, fatigue, and dizziness. Taking the dose with food helps, and some prescribers start at half a tablet to ease in.⁶

How to ask a prescriber

You do not need a TSM-certified clinician. You need a prescriber comfortable with naltrexone, which includes most primary care physicians, addiction medicine clinicians, psychiatrists, and several telehealth platforms focused on alcohol care.

A script that works:

"I want to try naltrexone for my drinking, using targeted dosing: 50 mg about an hour before drinking, instead of daily. It is sometimes called the Sinclair Method. Cochrane and the 2014 JAMA meta-analysis support naltrexone, and targeted dosing was tested in randomized trials in Finland. Would you prescribe it that way and follow up with me in a month?"

If your clinician is unfamiliar, offering the references at the bottom of this page is reasonable and normal. If they decline without engaging with the evidence, a second opinion is also reasonable and normal. Our guide on talking to your doctor covers the wider conversation.

What the first 90 days look like

Weeks 1 to 2. Side-effect window. Nausea and fatigue are the common complaints and usually fade. The one-hour rule feels awkward and requires planning. Expect drinking to feel different but not dramatically reduced.

Weeks 3 to 6. The rule becomes routine. Many people notice they stop finishing drinks, or that the second and third drink feels optional. The log matters most here, because change is easier to see on paper than to feel.

Weeks 6 to 12. This is where trend lines usually become undeniable in one direction or the other. A meaningful reduction in heavy drinking days by week twelve is a success signal worth continuing. Little or no change despite honest adherence is a signal to revisit the plan with your prescriber, where options include daily dosing, acamprosate, or other alcohol medications, and added behavioral support.

Throughout, pairing the medication with some structured support measurably helps. That can be a therapist familiar with CBT for substance use, a TSM peer community, or SMART Recovery meetings, which share the self-management ethos.

The bottom line

Naltrexone is one of the best-evidenced tools in alcohol care, and the Sinclair Method is a legitimate, trial-tested way to use it that does not require quitting first, entering a program, or telling an employer anything. The realistic promise is a gradual, measurable loosening of the craving loop for many of the people who follow the protocol consistently, with full extinction for some. The 78 percent figure describes the best published cohorts, not the median experience. Run it as a 90-day experiment with your prescriber, track honestly, and let your own data decide.

What to read next

• Medications for Alcohol Use Disorder: The Overview
• Supervised Ambulatory Alcohol Withdrawal
• Ways to Avoid Rehab: The Evidence-Based Guide

Sources