For starters, there’s no tobacco in e-cigs, and the contents aren’t wrapped in treated paper. Nothing is burned inside; instead, liquid ingredients are heated to create a vapor that is inhaled by the “smoker.” The modern electronic cigarette has three basic features: a power source, an atomizer and liquid (usually called e-liquid) inside a container and delivery system.

The simplest rechargeable models use a disposable pre-filled cartridge which is thrown away after the liquid is used up, although some companies offer the option of blank cartridges that can be refilled with e-liquid; the power source is the only component that is reused. In tank or PV units, the components are reused multiple times.

The Power Source

As you would probably guess, electronic cigarettes must have some type of power source. It’s usually a rechargeable battery, which is inside the long component of most e-cigarettes – the part that looks like the “tobacco” end of a regular cigarette. This is the heaviest part of an e-cig.

In most cartridge ecigs, the battery is activated when the user starts to inhale, providing power to the atomizer. On higher-end units, as well as a few cartridge models, the user needs to press a tiny button to activate the battery. This takes a little getting used to, but it also allows the vaper to take a longer inhale than the five seconds that some units allow. Batteries with variable power options are available for PVs (also known as mods), allowing experienced users greater control over the vapor that’s produced.

The Atomizer

In traditional rechargeable e-cigarettes, the atomizer is built into the disposable cartridge along with the e-liquid. The design of the atomizer in tanks and mods varies by model, but it’s a separate reusable component. They work in basically the same way, however. There is a wick (usually made of silica fibers, but sometimes made of hemp, cotton or a stainless steel mesh) which draws the e-liquid up from the container. Then a heating element powered by the battery “atomizes” the liquid, turning it into the vapor that’s inhaled.

Accomplished vapers or hobbyists who use personal vaporizers and are purchasing an atomizer (the atomizer usually comes standard in a tank starter kit) need to consider two simple electrical measurements: the voltage output of the battery and the resistance inside the atomizer; the right combination creates the right level of vapor and avoids the “burned” taste that sometimes results from too much power or too little resistance. Variable-voltage batteries are the easiest way to accomplish this; there are also charts available online that list the optimal voltage for the resistance of each atomizer. It should also be noted that atomizers (unless you’re using a cartridge system) do occasionally wear out and need to be replaced.

The E-Liquid

The component which may be most important to a user is the container, because it holds the e-liquid – which determines the way the vapor feels and tastes. The liquid is primarily a base of either propylene glycol or vegetable glycerin (or a mix of the two) with flavorings added to it. The varying of flavor agents creates the taste of a tobacco or menthol cigarette, or one of the savory or fruity flavors that are also available.

The manufacturer usually adds nicotine to the solution as well. There are various concentration levels available, from ultra light (with very little nicotine) to extra strong (equal to the level of nicotine found in non-filtered cigarettes). Most companies also offer a no-nicotine option.

E-liquid is already included in one-piece disposable e-cigarettes, and in the cartridges of traditional systems. For tanks and mods, the liquid must be poured into the tank made to hold it. Some experienced users enjoy buying different flavors of eliquid and mixing them to create their own unique flavors. It is less expensive to buy e-liquid than pre-filled cartridges, but many vapers find it less convenient to constantly refill cartridges. That’s the primary reason why the simple two-piece units used to outsell more complicated designs by a wide margin. However, as the electronic cigarette market begins to mature, tank systems have become more popular than ever and are cutting into sales numbers previously dominated by cartridge ecigs.

Are electronic cigarettes better for you than traditional tobacco cigarettes? Intuitively, it would certainly seem that way, and many health experts have offered the opinion that they are. But once again, there are no conclusive scientific studies that allow the industry to make that claim.

Individuals are free, of course, to look at what is known about tobacco cigarettes and what they do to the body – and then look at what’s not in e-cigarettes – and draw their own conclusions as many doctors have done.

Carcinogens

One of the main reasons people stop smoking is because traditional cigarettes contain a very high level of carcinogens, substances which have been proven to cause to cancer. The evidence is overwhelming linking tobacco smoking to cancer.

However, e-cigs contain virtually none of the ingredients found in a tobacco cigarette. That means the myriad number of studies on tobacco don’t really apply – new studies need to be done. A few have been. In a 2010 study conducted at the Boston University School of Public Health, the levels of carcinogens in e-cigarettes were much lower – in fact, as much as 1000 times lower – than in traditional cigarettes. The study also concluded that “few, if any” of the substances found in ecigs were likely to cause a serious health risk.

A more recent study was conducted by a group called “60 Million Consumers in France,” which claims that it found carcinogens in the vapor people inhale when using an e-cig. However, this research has come under fire from industry officials who say that the methodology was flawed; for example, the e-liquid was heated way beyond realistic levels before the vapor was analyzed.

And a study conducted by the Journal of Public Health looked at how many nitrosamines, a cancer-causing agent commonly found in tobacco, were present in electronic cigarettes. The study found that the amount was significantly lower than in traditional tobacco products. Nitrosamine levels in ecigs were actually comparable to that found in nicotine patches, which are approved for use by the FDA.

Those are just three examples of the limited research which has been done to date on the safety of ecigarettes. Even medical experts can’t come to the type of uniform conclusion that they’ve reached about tobacco cigarettes. Many offer their opinions, but just about all say more studies are needed.

Effects on the Lungs

There are relatively few studies on how electronic cigarette use affects the lungs – although, again intuitively, it would seem that this could be more of a concern than cancer. Researchers at the University of Athens in Greece conducted a study that found that individuals who used e-cigarettes over a long period of time could be at risk, and that e-cigs could damage the lungs. The study focused on the amount of airway resistance present in smokers, vapers and non-users. It found those who used e-cigarettes had a significant increase in the amount of resistance present in their airways for about ten minutes. That’s not as much resistance as was present in tobacco smokers, but the scientists concluded that there was still a risk to the lungs of those who vape. Only about 50 people participated in this study, once again showing that no large-scale research has yet been done.

Immune Responses

Another study done in Greece focused on the effects of electronic cigarettes on the body’s immune responses. Tobacco products increase the amount of lymphocyte, white blood cell counts, and granulocyte counts for an hour; that’s the body’s natural defensive reaction to the introduction of harmful substances. By contrast, the study showed that e-cigs did not have this effect; their users’ counts all remained normal. The conclusion was that electronic cigarettes did not stimulate the body’s natural defenses like tobacco products do, apparently because the vapor did not include harmful components which would trigger the body’s defenses.

Can They Help You Stop Smoking?

Another important question most people have is whether using an e-cig can help people quit smoking. The initial marketing behind electronic cigarettes emphasized their efficacy in this area. However, the US Food and Drug Administration objected to the claims because nothing had been proven and the devices weren’t regulated; the companies stopped using the “quit smoking” marketing campaigns after that.

A small amount of research has subsequently been done. The University of Auckland in New Zealand conducted a study on electronic cigarettes and smoking cessation, to determine whether people’s desire to smoke lessened if they used e-cigarettes. It found that the use of electronic cigarettes indeed reduced the desire to smoke, more than either non-nicotine e-cigs and or inhalers. Similar results were found in a study at the University of Catania in Italy, which concluded that e-cigarettes helped smokers to either reduce their tobacco intake or stop their use of tobacco completely, depending on their motivation – and claimed that e-cigarettes were actually helping to save lives.

Decades from now, this early research on electronic cigarettes will probably seem quaint. However, right now it’s all we have to go on – along with our own gut feelings about what’s in tobacco cigarettes compared to what’s in e-cigs.

What’s In E-Liquid

The primary ingredient in the production of e-cigarette vapor is a solution, called e-liquid. It usually contains some level of nicotine. Electronic cigarettes have a wick which extends into the solution and leads to a heating element known as the coil. When the e-cig is activated the coil warms the e-liquid solution, creating vapor.

E-liquid is a combination of several ingredients, with either propylene glycol (PG), vegetable glycerin (VG), or polyethylene glycol 400 (PEG 400) as the base. Additives in the solution add flavor. While the exact contents vary from manufacturer to manufacturer, here’s what’s most commonly inside.

Glycol or Glycerine Compounds

90 percent of most e-liquid is propylene glycol, vegetable glycerin, or PEG 400. Each of these products is approved for use through by the FDA in products such as injectable drugs, oral hygiene products, and pharmaceuticals. It is also used as a food additive (under the name E1520). The substance has no smell, no color, and has a sweet taste to it. It also has a low or non-existant level of toxicity. Through the last few decades, products using PG, VG and PEG 400 have been extensively tested and have not shown any cancer-causing properties. They don’t even cause skin sensitivity.That isn’t enough to definitively conclude that the primary ingredient in e-liquid is “safe,” but it’s certainly a good sign.

Nicotine

Nicotine is found in most e-liquid. It is actually not a chemical, but rather a natural product produced in the leaves of the tobacco plant, which stops insects from eating the leaves. When a mammal ingests nicotine it creates a stimulant effect. There’s actually very little nicotine in e-liquid (or in tobacco cigarettes, for that matter), only about one milligram. However it does create a dependency in users, and is the ingredient that create the continued desire to smoke.

In terms of nicotine’s toxicity, we do know that it is far from the worst component of the traditional cigarette. Experts agree that it is not as bad for you as many other chemical-based products in tobacco cigarettes. Nevertheless, it does have some negative effects in people, including an increase in adrenaline release which can cause rapid heartbeat, an increase in blood pressure, and a slowing of the release of insulin into the bloodstream (which can lead to or contribute to the development of diabetes). It can also cause shallow, rapid breathing, and has been linked to high cholesterol in some users. Finally, it can cause the burning of calories at a faster rate than normal.

Adding Flavorings

Manufacturers also add flavoring agents to the e-liquid, since nicotine itself does not have much of a flavor. In fact, during the nicotine distillation process, tobacco flavor is virtually removed from the nicotine used in an e-cigarette. That leaves an empty palette for manufacturers to add taste to their products. Additives are used to give e-cigs flavors similar to tobacco or menthol, or novelty flavors such as vanilla, strawberry, coffee or pina colada.

As for the health risks associated with e-liquid flavors, there’s been no real scientific study on the subject. There are said to be no known risk factors associated with these flavorings, according to manufacturers, but they do not provide a full list of their flavoring agents, just as cigarette manufacturers do not release a list of ingredients. The companies claim that there’s basically no difference between adding flavoring to an e-cig and adding it to a bakery product. But this cannot be definitively confirmed, however, without more research.

The Traditional Cigarette

Continuing with our intuitive approach to e-cigarettes and tobacco cigarettes, let’s take a look at what’s inside traditional cigarettes. The American Lung Association says that cigarettes have more than 600 ingredients, with more than 4000 chemicals present. Studies have shown that fifty of those ingredients are known to cause cancer, including acetic acid, ammonia, tar, carbon monoxide and acetone. None of them, however, have been found to be present in electronic cigarettes. Again, there are no definitive scientific studies showing that e-cigs are safe – but you can draw your own conclusions about the relative safety of each product.

One Other Fact

The United States government does not test e-liquid, most of which is manufactured in China where manufacturing standards are not as stringent as they are in America. Some American manufacturers of e-cigarettes have decided to sell only e-liquid made in the US; whether that’s for safety reasons or marketing reasons, only the companies know. Either way, at this point there are no documented cases of health issues associated with the use of e-liquid from either country.

At the time cigarette use was ubiquitous, with around 50% of adults partaking and most believing tobacco was relatively harmless. The first Surgeon General’s report hadn’t even been published yet. But Gilbert is said to have created his electronic cigarette because he saw what he considered to be an overuse of tobacco. Believing that tobacco was not good for the body, he set out to find a delivery method for nicotine which didn’t require the use of tobacco.

Various manufacturers approached Gilbert to discuss the manufacturing of the electronic cigarette. However, no actual contract or distribution ever came to fruition. Many believe that this was because of large-scale social acceptance of smoking and the lack of overall concern that smoking was a health risk. As a result, by 1967, the device was no longer discussed as a viable product and there was no public mention of a “smokeless cigarette” for many years.

First Generation Electronic Cigarettes

The next time the smokeless cigarette appeared was in 2003. At that time, a Chinese pharmacist named Hon Lik created a similar product. Credited as the modern inventor of a usable electronic cigarette, he designed a device more complex than the original version created decades before by Gilbert.

Hok Lik’s device used a piezoelectric ultrasound emitting element. Once the device was activated, it created an electric charge. The charge built up in solid materials, including crystals and proteins. Whenever it was activated, the charge worked to vaporize a pressurized jet of liquid. This liquid was a nicotine solution, with a small amount of nicotine diluted in a propylene glycol solution.

A few things stood out in this version of the electronic cigarette. It did use a solution containing nicotine just as Gilbert’s did. However, the vapor produced looked very much like traditional cigarette smoke. The user was able to breathe in this vapor, bringing the nicotine into their lungs and later into their bloodstream, providing a very similar experience to traditional smoking.

To improve the electronic cigarette further, Hon Lik devised a method that allowed him to put the propylene glycol/nicotine solution into a plastic cartridge. When the user finished using the device and the solution was gone, he could simply toss out the cartridge instead of the entire device. This unique design is still one of the most important components in the design of today’s electronic cigarette.

Electronic Cigarettes Hit the Market

The rapid success of the e-cigarette was certainly helped by the fact that the company Hon Lik worked for supported his research and helped in the production of the product. By May of 2004, Hon Lik’s device was on the market in China, marketed to those who were trying to quit smoking. Advertising campaigns focused on the e-cigs being a “healthier” option than traditional smoking. A year later, the company began international export of the electronic cigarette. By 2007, the company held international patents for the product.

The company Hon Lik worked for was originally called Golden Dragon Holdings. It later changed its name to Ruyan, which means “resembling smoking” in Mandarin. Today, Ruyan is the largest manufacturer of electronic cigarettes in the world.

Increasing Growth and Popularity of the Electronic Cigarette

Unlike that of Gilbert, the new version of the electronic cigarette caught the public’s imagination quickly. This was largely because of of the overwhelming medical evidence on the hazards of smoking, which simply didn’t exist in Gilbert’s day. That meant there was a ready-made market for a cigarette alternative, whether it was among smokers wanting to quit, or those searching for a way to still “smoke” in a world where that was becoming more and more difficult. And many potential manufacturers were quick to realize the potential profits to be realized; they quickly jumped on the bandwagon.

In Europe, e-cigs became very popular and readily available. And a few years later when the United States allowed the importation of electronic cigarettes from Chinese manufacturers, the market grew even faster. In fact, electronic cigarettes have become the fastest growing segment of the smoking industry in America. In 2010, estimates indicate that about 750,000 units were sold in the United States. In 2012, that number hit 3.5 million. Exponential sales growth has been seen in Europe, and around the world, as well.

This soaring demand is certainly one factor in the debate over regulation of electronic cigarettes. In fact, some credit the demand in Europe as a major factor in the EU Parliament’s decision not to regulate e-cigarettes as medical devices – since such regulation would make it much harder to buy ecigs. With the e-cigarette industry still in its relative infancy, all indications are that demand will continue to grow, even if laws and ordinances make it more difficult to purchase or use the products.