[Epistemic status: The claims here are based on my attempt at a thorough reading of peer-reviewed research. I have no formal medical training beyond college level biology and chemistry. I have a pro-harm reduction bias, both as an advocate in my local community and as a recipient of funding from an aligned organization with past ties to the tobacco industry. For more detail, please see the About page.]

Introduction

This post continues the examination of tobacco harm reduction (THR) advocates’ core claims from an effective altruist (EA) perspective. The last post looked at the safety of nicotine and what it implies for the tractability of THR. This one will investigate the assertion that for smokers trying to quit, using a noncombustible product like a vape or a nicotine pouch is the method likeliest to lead to success.

Like the level of health risk from smokeless products, understanding how effective they are in reducing smoking is critical in determining whether THR is a tractable method. If they don’t work well enough, then money spent promoting them to smokers isn’t well used, no matter how safe they are. If they work better than other existing approaches, that implies a pretty urgent need to let smokers, and the health care professionals advising them, know, so that they can switch and reap the health benefits as soon as possible.

Support for this claim comes from many corners, including consumers, governments, and academia. Advocates have called Juul, one of the best-known noncombustible products, the “most successful anti-smoking device ever made.” The UK National Health Service calls vaping “one of the most effective ways to quit smoking.” A study in Discover Social Science and Health claims snus is “most effective and efficacious method for quitting smoking in Norway.”

On the other hand, skeptics claim that while the evidence around the effectiveness of reduced risk products for cessation is still evolving, there are other “proven” and “approved” methods that do work. The American Lung Association urges smokers “Quit, Don’t Switch” to vaping because the “Food and Drug Administration has not found any e-cigarette to be safe and effective in helping people quit.” Many university health centers discourage nicotine pouch use for cessation as there is “no data to show nicotine pouches as a safe or effective way to quit.”

What methods exist?

To gauge how credible the claim about the effectiveness of reduced harm products is, it helps to understand the baseline of how well other methods work. Because of the variety of ways and contexts in which people smoke across the world, it’s hard to put a single number on any method. That said, we can infer some rough figures from the available data.

The success rates of unassisted quit attempts for daily smokers tend to fall into the 3-5% range, so an average smoker could expect one in every 20-30 attempts to succeed. In most parts of the world, while the least effective, this is still the most common method of successfully stopping, because it’s used by a large majority of people attempting to quit. For smokers in less affluent countries, few additional tools are available or affordable. But even in a recent analysis in the US, more than two thirds of former smokers reported having quit this way.

Counseling, nicotine replacement therapy, and pharmaceuticals (primarily bupropion and varenicline) are the three mainstays of the WHO’s current clinical treatment guidelines. By and large, none of them work very well - any given quit attempt is a lot more likely to fail than succeed, no matter what combination of tools is used.

Counseling and NRT

Providing behavioral support on how to navigate the challenges of stopping smoking appears to improve the success rate slightly. “Support” is a pretty broad term for different types of interventions including individual sessions with an expert, text messages, and financial incentives, but two recent meta-analyses estimated these can, on average, bring the quit rate up by about half, to around 10%.

Nicotine replacement therapy lies on the boundary between pharmaceutical and non-pharma tools as there are both prescription and over the counter products available. A Cochrane meta-analysis indicated they can raise the odds of a successful attempt to 6% from an 4% average in the control groups. However, observational data indicate that effectiveness in a non-clinical setting may not be as high: a survey study in England showed no benefit of over the counter products compared to unassisted quitting, and in the US, the introduction of over the counter NRT in 1996 didn’t result in a measurable increase in quit attempts nor in successful cessation in the population.

Pharmaceuticals

The two most commonly used and studied pharmaceutical products recommended to assist cessation are bupropion and varenicline. Data on the effectiveness of both is somewhat sparse as they are neither as well known nor as accessible as other methods, requiring a doctor visit and prescription in most countries.

The idea behind the use of bupropion is that it blocks nicotinic acetylcholine receptors, thereby reducing the pleasure experienced when smoking. Randomized, controlled trials show a roughly 20% 12-month abstinence rate for people using it, although most of these are of fairly small groups of a few hundred people, and some observational data even suggest no long-term benefit outside of the study setting.

Varenicline has a similar mechanism of action, binding to nicotinic receptors to reduce nicotine cravings. It appears to result in a similar increase in quit rate in RCT’s, with 12-month abstinence in most studies around 15-20%. In head to head comparisons with bupropion, it tends to do a bit better.

Alternatives

There are a number of tools beyond the WHO’s recommendations, both behavioral and chemical, that seem to have potential to help, but lack robust or large scale evidence. Hypnotherapy has been tried and studied a bit, but doesn’t seem to show a measurable effect. Cytisine is a plant-derived nicotine receptor agonist that’s been used in Eastern Europe for decades and from which varenicline was derived, shows roughly similar effectiveness to other pharmaceuticals although with more limited and low quality data. Finally, psychedelics show significant promise in sustained cessation, but with very limited data. In a small pilot study, more than half of smokers who went through three psilocybin experiences with subsequent counseling were still abstinent a year and a half later.

Effectiveness of reduced risk products

So how do reduced risk products compare? There have been both RCT’s of trials in clinical settings - giving people various products along with some instructions on how to use them - and analyses of observational data attempting to determine trends when either a product appeared on or disappeared from the market in a specific area, or regulations were tightened or loosened.

Clinical data

The most up to date and comprehensive review of RCT’s comes from the Cochrane Library, which looked specifically at e-cigarettes, comparing them to NRT and behavioral support. Their headline conclusion was that there is, as of 2025, high certainty evidence that vapes with nicotine are a bit over 50% more effective than NRT, raising the odds of cessation at twelve months to 10% compared to 6%. Another systematic review showed a similar improvement of vaping over both and NRT and placebo. The only head to head comparison between varenicline and vaping showed about the same level of effectiveness. Heated tobacco appears to perform similarly or slightly better in the limited RCT’s available. Snus hasn’t been studied much in a clinical setting, although one small study in the US showed similar effectiveness to an NRT product while another in Sweden didn’t produce a significant difference between real and placebo snus.

Observational analyses

Almost nobody in the real world encounters noncombustible products in a clinical setting. Observational data provide a window into real-world effectiveness, with the obvious caveat that they can only demonstrate correlation. Across a number of countries, a number of signs point towards the conclusion that broader use of e-cigarettes, snus, and heated tobacco products results in significant reductions in smoking at the population level. These reductions are greater than any observed after the introduction of the tools detailed above.

For snus, this is most obvious from data in Scandinavia, where it is most commonly used, and has been for decades. As early as 2003, Sweden had the lowest smoking rate in Europe at 18%. While its tobacco control measures didn’t and still don’t differ significantly from its neighbors, it has, as of 2024, become the only country in the world to have started with a significant share of smokers (about half of all Swedish men smoked in 1960) and driven it down to below 5%. Similarly, in Norway, a big drop in smoking has coincided with strongly increased use of snus in the past twenty years. While these are, again, only correlations, they are quite large, and confirmed by retrospective analyses of specific populations in both countries. I couldn’t find an alternative candidate for a plausible explanation of the large difference other than the widespread use of snus and the fact that it has remained legal in these two countries while the EU banned it everywhere else.

In the case of e-cigarettes, population data show a similar correlation, with an increase in cessation under liberalized policies and decreases in places where regulations become stricter. In England, the government announced in 2017 that the smoking quit success rate jumped as e-cigarettes became popular to the point of becoming the most-used quitting aid, a finding confirmed by time series analyses. Similar correlations were observed by researchers in the USA. Notably, states that implemented partial or full bans appeared to see corresponding increases in cigarette sales. A similar study on the relationship between vape flavor bans and young adult smoking showed the same pattern. Researchers in New Zealand identified a similar pattern when comparing the drop in the smoking rate to that of Australia, with the populations vaping the most (young adults) also showing the biggest drops in smoking.

For heated tobacco products, the data is more limited, but trends in at least one country, Japan, point to a potentially large effect in a similar direction. Cigarette sales began dropping more steeply after the introduction of IQOS in the country, a trend that has continued until this day. HTP’s account for more than a third of tobacco sales overall and have overtaken cigarettes for the first time in Tokyo.

Conclusions

So are the advocates correct in claiming that noncombustibles represent the most promising tool for the average person looking to quit smoking? While the data from RCT’s seems to indicate a rough tie at the top, the population level data is a pretty strong sign that they’re right. The reason is highlighted in another study surveying quit attempts in the UK: vapes are an order of magnitude more popular than any other cessation method, so the sheer number of people using them can’t help but result in many more people giving up smoking than through other means.

One can speculate about why people prefer vaping, snus, and their ilk to pharmaceutical approaches or counseling. I’ll try to explore this further when looking at the normative claims made by advocates, but one theme often stands out when I talk to users of these products: they are commercial products marketed to help them meet their goals in a non-coercive way. It’s a lot more comfortable to be treated like a person trying to find a less risky alternative to something they enjoy doing than a patient with a disorder to be fixed through medical intervention. They fit the spirit of harm reduction in the sense that Shaun Shelly defines it: “helping them achieve their drug use aims (including abstinence) in the way that causes the least harm to them.”

Where does this leave EA’s wondering about tobacco harm reduction as a cause area? Some of the questions in the last post about cost-effectiveness and the degree to which it’s worthwhile to actively promote it remain open. That said, if there are reasons to oppose the prioritization of THR as a cause area, I think the case is strong that concerns about whether it actually lowers smoking better than other methods shouldn’t be one of them.