Cytisine: The Quit-Smoking Drug America Lacks

If you’re trying to use cytisine to quit smoking, you’re looking at a drug that has been hiding in plain sight for over half a century. Prescribed in Bulgaria and Poland since the 1960s. Backed by randomised controlled trials. Similar efficacy to the most effective prescription cessation drug on the market. And until very recently, virtually unknown outside Eastern Europe.

That changed in January 2024, when the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) granted cytisine a marketing authorisation under the brand name Asmoken. It became the first new quit-smoking drug licensed in the UK in over 15 years.

And it still isn’t available in the United States.

Here’s what the evidence says, who can get it, and why this matters for anyone trying to quit.

What Is Cytisine?

Cytisine is a plant-based alkaloid extracted from the seeds of Cytisus laborinum (golden rain tree). It’s a partial agonist of the nicotinic acetylcholine receptor — the same receptor subtype that nicotine targets when you smoke or vape. If that mechanism sounds familiar, it should. It’s the same mechanism as varenicline (Champix/Chantix), which was the most effective quit-smoking drug available until Pfizer discontinued production in 2021 due to manufacturing contamination.

The pharmacology works like this: cytisine binds to the alpha-4 beta-2 nicotinic receptor and partially activates it. “Partial agonist” means it stimulates the receptor enough to reduce withdrawal symptoms and cravings, but not enough to deliver the full dopamine hit that nicotine provides. If you do smoke while taking it, the drug blocks nicotine from binding properly, so the cigarette feels unsatisfying.

This is exactly how nicotine hijacks your brain’s reward system — and cytisine disrupts that process at the receptor level.

The treatment course is 25 days. You start on day one while still smoking, with six tablets per day, and taper down to one or two tablets per day by the end. You’re supposed to stop smoking entirely by day five. The whole thing costs a fraction of what varenicline or even a month of nicotine patches costs.

The Evidence: 50 Years of Data

Eastern European History

Cytisine was first approved in Bulgaria in 1964 under the brand name Tabex. It’s been available continuously in Bulgaria, Poland, and several other Eastern European countries since then. Millions of courses have been dispensed. The safety profile over five decades of real-world use is extensive.

For years, Western researchers largely ignored this data. The early studies were published in Bulgarian, Polish, and Russian medical journals. They weren’t randomised controlled trials by modern standards. The drug was cheap, unpatented, and had no pharmaceutical company with the budget or motivation to run expensive Western-standard trials.

That started to change in the 2010s.

The Walker Trial (2014) — New Zealand

The pivotal study that brought cytisine to Western attention was a randomised, placebo-controlled trial published in the New England Journal of Medicine by Walker et al. in 2014. The study enrolled 1,310 adult smokers in New Zealand and randomised them to cytisine or placebo for 25 days.

Results at one month:

Group	Continuous Abstinence
Cytisine	40%
Placebo	31%

At six months: cytisine group had significantly higher continuous abstinence — odds ratio 1.74 (95% CI: 1.38–2.19). Self-reported outcomes were biochemically verified.

This was the first large, rigorous, Western-standard RCT to demonstrate that cytisine works. The NEJM publication forced the global cessation community to pay attention.

Cytisine vs. Nicotine Replacement Therapy (2014)

The same research group published a head-to-head trial comparing cytisine against nicotine replacement therapy in the same year. Walker et al. randomised 1,310 smokers to either cytisine (25 days) or NRT of their choice (8 weeks of patches, gum, or lozenges).

Continuous abstinence at six months:

Group	Abstinence Rate
Cytisine	22%
NRT	15%

Cytisine was superior to NRT — not just cheaper, but more effective. The trial was designed as a non-inferiority study, and cytisine exceeded the threshold by a wide margin. For context, NRT increases quit rates by 50–60% over placebo. Cytisine did better than that.

Cytisine vs. Varenicline (2021)

The comparison everyone was waiting for. Courtney et al. published a randomised trial in JAMA Internal Medicine in 2021 comparing cytisine (25-day course plus 12 weeks of behavioural support) against varenicline (12-week course plus the same behavioural support) in 1,452 smokers.

Continuous abstinence at seven months:

Group	Abstinence Rate
Cytisine	11.7%
Varenicline	13.4%

Cytisine met the non-inferiority threshold. The difference was not statistically significant. The authors concluded that cytisine was “non-inferior to varenicline” for smoking cessation.

Here’s what makes that finding remarkable: cytisine’s treatment course is 25 days. Varenicline’s is 12 weeks. Cytisine costs roughly £20–£100 for a full course depending on the market. Varenicline, when it was available, cost £150–£400 per course in the UK and $400–$600 in the US.

Similar outcomes. A quarter of the treatment duration. A fraction of the price.

Why Cravo Hates Cytisine

Your cravings don’t care about pharmacology papers. They care about keeping you hooked. And a drug that blocks the receptor — that makes the cigarette feel hollow and pointless — is a direct threat to the cycle that keeps you reaching for the next one.

Cytisine essentially takes Cravo’s main trick away. The dopamine reward loop that drives nicotine addiction needs the receptor to be available. Block it with a partial agonist, and the craving still shows up, but its leverage is gone. The cigarette doesn’t deliver. The vape doesn’t satisfy. The habit starts to feel like effort without payoff.

That’s why pharmacological support works. Not because it makes quitting painless — nothing does — but because it shifts the odds in your favour. Whether you go cold turkey, use NRT, or take cytisine, the goal is the same: break the reinforcement loop long enough for your brain to start healing.

UK Licensing: What Happened in 2024

In January 2024, the MHRA granted a marketing authorisation for cytisine (brand name Asmoken, manufactured by Achieve Life Sciences via Sopharma, the original Bulgarian producer). This made cytisine available by prescription across the UK.

Key details of the UK licensing:

• Prescription only — you need a GP or smoking cessation service to prescribe it
• 25-day course — the standard regimen, with a tapering dose schedule
• NICE guidance pending — at the time of writing, the National Institute for Health and Care Excellence (NICE) has not yet issued formal technology appraisal guidance, which means NHS funding varies by local commissioning decisions
• Available via private prescription — some online pharmacies and smoking cessation clinics can prescribe and dispense it directly

The licensing was based on the body of evidence described above, plus additional safety and pharmacovigilance data from decades of Eastern European use. The MHRA concluded that the benefit-risk profile was favourable for adults who want to quit smoking.

Why Isn’t Cytisine Available in the US?

The short answer: the FDA approval process requires specific Phase III trials conducted under an Investigational New Drug (IND) application, and those trials take years and cost hundreds of millions of dollars.

Achieve Life Sciences (now Emisphere Technologies) has been running US-targeted clinical trials for cytisine under the brand name Todacitan. Phase III results are expected, but the FDA pathway is slow, expensive, and unforgiving. The drug’s low cost is, paradoxically, part of the problem — the potential revenue doesn’t easily justify the investment required for FDA approval, especially when the compound is off-patent and difficult to protect commercially.

For American readers: cytisine is not legally available in the US by prescription. Some people order Tabex online from Eastern European pharmacies, but this is unregulated, potentially illegal depending on your state, and means you’re taking a drug without medical supervision or quality assurance from a US-recognised source.

The better path for US-based quitters right now is to discuss available options with your doctor — including NRT, bupropion, or the behavioural strategies in our how to quit smoking guide.

Side Effects and Safety

Cytisine’s side effect profile is generally mild and well-documented across five decades of use:

Common side effects:

• Nausea (the most frequently reported — usually mild and dose-related)
• Headache
• Dry mouth
• Gastrointestinal discomfort
• Insomnia or vivid dreams

Less common:

• Dizziness
• Increased heart rate
• Elevated blood pressure

Contraindications:

• Pregnancy and breastfeeding
• Recent cardiovascular events (heart attack, stroke within three months)
• Unstable angina
• Severe renal impairment

The 2014 Walker trial reported that adverse events were slightly higher in the cytisine group than placebo, but serious adverse events were similar between groups. The 2021 Courtney trial found that cytisine had fewer adverse events than varenicline overall, with nausea being more common with varenicline.

One important caveat: cytisine has less cardiovascular safety data than varenicline had before its withdrawal. The Eastern European pharmacovigilance data is reassuring but not as granular as what the FDA demands. If you have a heart condition, talk to your doctor before starting any cessation medication.

How Cytisine Compares to Other Options

Here’s where every major quit-smoking approach sits in the evidence:

Method	Typical Quit Rate (6 months)	Duration	Cost (UK)	Prescription?
Cold turkey (no support)	3–5%	—	Free	No
NRT (combo)	15–25%	8–12 weeks	£20–£60	No (OTC)
Bupropion	15–20%	7–12 weeks	£40–£80	Yes
Cytisine	15–22%	25 days	£20–£100	Yes
Varenicline	20–25%	12 weeks	Unavailable (UK)	Yes
Behavioural support alone	10–15%	Varies	Free (NHS)	No

The standout feature of cytisine isn’t that it’s dramatically better than everything else — it’s that it achieves comparable results in less time, at lower cost, with a well-tolerated side effect profile. For healthcare systems trying to help millions of smokers quit, that cost-effectiveness changes the calculation entirely.

For you personally, the difficulty of quitting doesn’t change based on which tool you use. Every method still requires dealing with withdrawal, breaking habits, and rebuilding routines. Cytisine just gives your brain more support during that process.

How to Access Cytisine in the UK

If you’re in the UK and want to try cytisine:

1. Talk to your GP. Ask about Asmoken (cytisine) as a quit-smoking option. Some GPs may not be familiar with it yet — the MHRA licensing is recent and NICE guidance is still developing.

2. Contact your local Stop Smoking Service. NHS smoking cessation services are free and can prescribe cessation medications. Availability of cytisine may depend on local formulary decisions.

3. Private prescription. Several online pharmacies and telehealth services now offer cytisine by private prescription. Expect to pay for both the consultation and the medication.

4. Combine it with support. The trial evidence consistently shows that pharmacological treatment combined with behavioural support produces better outcomes than medication alone. The NHS Stop Smoking Services, the Cravo app, or even a structured quit plan all count.

Frequently Asked Questions

Is cytisine the same as varenicline (Champix)?

No. They’re different molecules with the same mechanism of action — both are partial agonists at the alpha-4 beta-2 nicotinic acetylcholine receptor. Cytisine is a natural plant alkaloid; varenicline is a synthetic drug that was actually designed based on cytisine’s structure. Think of them as cousins, not twins. Cytisine has a shorter half-life and a shorter treatment course (25 days vs. 12 weeks).

Can I use cytisine and NRT at the same time?

This is not generally recommended. Both act on nicotinic receptors, and combining them could increase side effects (particularly nausea and cardiovascular symptoms) without clear evidence of improved efficacy. Talk to your prescriber before combining any cessation medications.

Does cytisine work for vaping?

The clinical trials were conducted with cigarette smokers. There are no large RCTs specifically studying cytisine for vaping cessation. However, the pharmacological mechanism is the same — vaping delivers nicotine to the same receptors that cytisine partially blocks. Many clinicians are prescribing it off-label for vapers, and the rationale is sound, but the evidence base is not yet there.

How long before cytisine starts working?

The standard protocol has you start cytisine while still smoking, with a quit date on day five. Most people report reduced satisfaction from cigarettes within the first two to three days. By day five, smoking should feel noticeably less rewarding, which is the intended effect — the partial agonist is occupying the receptors before nicotine can.

What if I relapse while taking cytisine?

Relapse during a quit attempt is common and doesn’t mean the method has failed. If you smoke while taking cytisine, the cigarette will likely feel less satisfying than usual. The standard advice is to continue the course and try to stop again as quickly as possible. If you’ve completed the 25-day course and relapsed afterwards, talk to your doctor about repeating the course or trying a different approach.

Is cytisine safe long-term?

Cytisine is designed as a short-term treatment (25 days). There is limited data on repeated courses or long-term use. The five decades of use in Eastern Europe haven’t raised major long-term safety signals, but the drug isn’t intended for indefinite use the way some NRT products are.

The Bigger Picture

Cytisine’s story is partly about pharmacology and partly about how broken the global drug approval system is. Here is a drug that costs pennies to produce, has been used safely by millions of people, and performs as well as the best prescription option available. It took 60 years to reach the UK. It still hasn’t reached the US.

The World Health Organisation added cytisine to its Model List of Essential Medicines in 2023. That’s the WHO’s way of saying: this drug is safe, effective, and should be available everywhere.

For now, if you’re in the UK or Europe, cytisine is one more tool in your arsenal. If you’re in the US, it’s one to watch. Either way, the evidence is clear that combining pharmacological support with a structured quit plan — whether cold turkey or gradual — gives you the best chance.

Track what you’re saving as you quit with our Savings Calculator. And if you want a quit companion that understands the science and fights your cravings alongside you, join Cravo.

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Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Cytisine is a prescription medication in the UK. Always consult your doctor or a qualified healthcare professional before starting any cessation medication. Do not stop or change prescribed medications without medical guidance.

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