The Difference Between Mouth to Lung (MTL) & Direct Lung (DL) Vaping

One of the great things about vaping is that there are different styles and ways to do it. It’s all down to personal preference, but to make a choice, you will want to know what options are available. 

A commonly asked question is; what’s the difference between mouth to lung (MTL) and direct lung (DL) vaping? In this article, we will dig deep down into explaining both styles, what you’ll need, and who each style will suit. 

What is Mouth to Lung (MTL) Vaping

Mouth to lung vaping (also referred to as MTL) has been around since vaping was created. In fact, it used to be the only style of vaping. 

The term refers to how vapor is inhaled from an electronic cigarette. MTL is when the vapor is first drawn from a device by sucking with the mouth before being inhaled into the lungs.

If you have ever smoked a cigarette, you’ll already be familiar with a mouth to lung style of vaping, as it is the same in concept (except, you know, vaping is much better than smoking). 

Imagine the vapor having two stages on its journey. First, it is taken into the mouth. Then, once it’s there, it is inhaled down into the lungs.

What Hardware do You Need to MTL Vape?

The good news is that MTL is probably the easiest style to adopt. 

Generally, pod systems, such as the Juul, Smok Novo X, and Uwell Caliburn G, are all designed to be used in a mouth to lung style. They work straight out of the box with minimal setup required. 

Alternatively, you might want to buy an atomizer (also called a ‘tank’) and a battery (or ‘mod’) separately. Here are a few things that are common in MTL setups: –

Restricted Airflow

To give the user something to ‘pull’ against, the airflow on MTL tanks tends to be a lot more restricted. You’ll notice that on MTL tanks that the airflow holes tend to be really small. 

If you take a look at a classic MTL tank, like the Vandy Vape Berserker V2 Mini, you’ll see that it has tiny holes. This twinned with a smaller mouthpiece gives a really tight draw.

Smaller Tanks

Because MTL setups don’t vaporize huge amounts of ejuice, they don’t need to be refilled often. There isn’t the need for a massive reservoir. They are often a little more compact in size.

Smaller Higher Resistance Coils

The aim of MTL tanks is to produce a small amount of vapor. As a result, they don’t have huge low resistance coils. Instead, you’ll find that the coils are rated with much higher resistance coils than typical ‘sub ohm’ setups. This also requires less power being pushed through the coil to heat it. 

Smaller Battery

Because there is less power pushed through the coil, MTL setups tend not to need a large battery. As a result, the mods used with these setups can be much smaller. 

What Ejuice to Use for MTL Vaping?

Your choice of juice can make a huge difference with MTL vaping. Ejuice is generally made from a few things:-

• Nicotine liquid
• A base liquid, either Propylene Glycol (PG) or Vegetable Glycol (VG)
• Flavorings

The first two on the list are the areas you need to consider when it comes to MTL.

Because of the devices used, MTL produces a relatively small amount of vapor. If you are looking to satisfy a nicotine craving, you may need a higher-strength juice. You can use regular juice or nicotine salts. Nicotine salt juices cause nicotine to enter the bloodstream faster, and you feel the effects much quicker.

The base liquid has a real bearing on your vaping experience too. VG is very smooth and tends to lack a distinctive throat hit. PG, on the other hand, gives a strong throat hit. 

Depending on your choice of juice, some users may find VG-based ejuices a little too smooth. If you are using a vaping device to replace smoking, you might miss that distinctive ‘throat hit’. In which case, a higher PG-based juice may be better. 

What Coil Resistance to Use for MTL Vaping?

Generally, coils for MTL vaping tend to be smaller with higher resistance. Anything around and above 1 ohm is probably better for MTL vaping. Because the coils have high resistance, they heat up quickly even with low power. 

Remember how we said that MTL devices have tight and restricted airflow? That means there is less air going over the coil. As a result, it is easy to burn coils at high power settings. As a general rule, MTL vape devices will have a high resistance coil used with a relatively low power setting.

What are the Advantages to MTL Vaping?

There are quite a few advantages to MTL. Let’s take a quick run-through

• Easy to get started. 

As we have seen, there are many devices out there that will allow you to MTL vape ‘straight out of the box’.

• The style most similar to smoking

If you are switching to vaping as a means to stop smoking, you’ll probably find mouth to lung vaping to be similar in terms of feel and sensation. 

• Better battery life

Because MTL vapes use smaller, high resistance coils, you don’t need a lot of power to produce vapor. This is great as it means your mod battery lasts longer.

• You use less juice

MTL doesn’t produce lots of vapor and the ejuice used in MTL vaping tends to be higher in nicotine strength. As a result, you’ll find that even a small bottle of ejuice lasts a longer amount of time. 

• Devices tend to be smaller

MTL devices are generally pretty compact. Pod-style vapes are small enough to fit into a pocket. Because mod and tank MTL style devices use less power, you’ll also find that the mod doesn’t need to be huge to accommodate many batteries.

• Less obtrusive in public

MTL devices produce less vapor. If you are conscious about blowing huge clouds or vaping more inconspicuously, they are ideal. 

• MTL devices are cheaper

MTL devices are available in a great range, and it is easy to find something that can fit any budget. You can even purchase one-time-use disposable vapes.  

Is MTL Right for You?

MTL is a great entry point into the world of vaping. As to what level you enter, this is entirely your choice. Most vapers start with a simple pod system. Alternatively, you could go slightly more advanced with a pen kit.

MTL could be right for you if you are new to vaping. Because the sensations associated with MTL vaping are close to smoking, they are ideal for people looking to quit the ‘stinkies’. This, twinned with higher concentrations of nicotine in the Ejuice, makes MTL vapes a great choice to help quit smoking for good.

Still not sure?

There are alternatives. Let us introduce you to the world of direct lung vaping….

What is Direct Lung (DL) Vaping?

Okay, now you have an idea on the concept, let’s switch it up a gear. 

Direct lung vaping (or DL for short) is traditionally thought of as ‘cloud chasing’. If MTL vaping is sipping through a straw, DL is breathing through a snorkel.

It works like this…

Remember how we said MTL vaping is a two-stage process? DL vaping is one stage. 

DL devices generally tend to be higher-powered devices with really draughty airflow.

The vapor is drawn direct from the atomizer into the lungs. You literally inhale through the device, taking a good lungful of vapor in along the way. 

You’ll have no doubt seen people direct lung vaping, as it is characterized by the user being able to blow out a huge plume of vapor. It’s pretty far removed from what people would consider ‘smoking’, and is a little more ‘specialized’. 

What Hardware do You Need to DL Vape?

If you are looking to get into DL vaping, you will notice that the equipment used is slightly different. While the principle is identical to MTL devices, there are some key differences:

Greater Airflow

With direct lung vaping, you are inhaling the vapor straight into your lungs. As a result, there needs to be more airflow to allow you to do this. Classically you can expect to see large air holes at the base of a tank. 

A great example can be seen on a tank like the Smok Tfv16 Lite sub-ohm tank. This is normally combined with a wider mouthpiece (also called a ‘drip tip’) to allow maximum airflow through the device. 

Here’s another example by Hellvape. Can you see the difference between this and a MTL tank like the Hellvape Vertex? 

Lower Resistance and Higher Power

You’ll generally hear DL tanks referred to as ‘sub-ohm’. This means that the heating element’s internal resistance is less than 1 ohm. This depends on the material that the coil is made of, but by using a larger, lower resistance coil, there is a greater surface area being heated. 

As a result, more ejuice is vaporized, leading to bigger clouds. 

However, a big coil needs something extra…

More Power = Bigger Battery

In order to get a low resistance coil to a suitable temperature, you actually need to push more power through it. While you could use a small mod, you’ll find that the battery runs out pretty quickly. 

As a result, you will need to use a mod that has higher battery capacity. For this reason, you’ll see a lot of sub-ohm vapers use a device with multiple batteries, normally a square-shaped box mod, such as the Vandy Vape Gaur-21.

These devices are capable of a high-power output, and because they have multiple batteries, they last a lot longer when vaping with a sub-ohm setup.

What Ejuice to Use for DL Vaping

As we saw with MTL vaping, the ejuice makes all the difference.

Remember our list of the elements in ejuice? Here’s a quick reminder: –

• Nicotine liquid
• A base liquid, either Propylene Glycol (PG) or Vegetable Glycol (VG)
• Flavorings

Again the first two elements on our list are the most important (but we love the flavor too)…

It isn’t recommended to vape high-strength nicotine liquids when DL vaping. You are delivering huge clouds of vapor directly to your lungs. As a result, it is really easy to overdo it and make yourself feel nauseous. We find a nice middle ground is around 6% nicotine (when compared with MTL juices of 18%, you can see this is a significant reduction)

Remember what we said about nicotine salts juices too? They deliver nicotine into the bloodstream much faster. It is far better to stick with regular nicotine ejuices when DL vaping, to avoid making yourself feel sick.

The VG or PG element is also important. VG tends to make much thicker and denser clouds. It is also kinder on the throat, which is exactly what you want when you breathe in larger volumes of vapor. But…

VG is also much thicker than PG, it doesn’t soak the cotton in coils quite as freely, and as a result, you can get the occasional ‘dry hit’ if you are making your own coils and don’t wick your coil in the right way. This can be a little fiddly, especially for a brand-new beginner. 

The solution could be to choose a liquid with a blend of VG and PG. You’ll be able to thin your juice down with the addition of a little PG but still chuck massive clouds!

What Coil Resistance to Use for DL Vaping 

Coil choice is a little different when it comes to DL vaping. Generally, you will want to aim to purchase sub-ohm coils (coils with a resistance less than 1.0 ohm). The type depends heavily on which tank you have purchased.

There is even the option to make your own coils and fit them in a rebuildable tank; the Wasp Nano RTA is a great example of a DL setup that is easy to use.

To get more vapor, you will need to use higher power, and for that, you need a coil that is of low resistance. Aim for coils that have a rating of less than 1 ohm. And remember, the lower the resistance, the more power will be needed to get the coil to a good temperature.

What are the Advantages to DL Vaping

DL vaping has plenty of advantages. Here are some reasons to try it: –

• Huge clouds

Because DL vaping favors juices higher in VG, paired with bigger coils, more airflow, and higher power, you will be able to blow huge clouds. There are even competitions where people do tricks with the vapor! Check this out… 

• Better flavor

Do you like to take a sip of something or a gulp? Because there is more Ejuice being vaporized on the coil, combined with higher airflow, you’ll find that juices taste stronger and more intense.

• More customizable

If you think tweaking your setup might be fun, then DL will allow you to do this. Rebuildable tank atomizers tend to have huge build decks, allowing you to customize the kinds of coils you install. Most mods come with a range of customization options too, where you can change the power and mode easily.

• DL is kinder to your throat

A major complaint of new vapers is that they suffer from a sore throat. Because DL vaping tends to use juices with a higher VG concentration, this is less of an issue. It is a smoother vaping experience.

• Less nicotine

There is more vapor produced and inhaled with direct lung vaping. Because of this (if you’ve read our guidance above), you will find that juices designed to be DL friendly have a much lower nicotine level. So, if you are looking to reduce your nicotine intake, it’s a great solution.

• It can be cheaper

The initial outlay for a great DL setup might be slightly more expensive than buying a simple pod or vape pen. (That said, you can pick up a sub-ohm starter kit pretty cheap). However, if you decide to get into the world of building your own coils, you can make hundreds for a few dollars. 

Is DL Right for You?

Direct lung vaping is a natural progression from MTL. Most vapers want to really taste the juice and are looking to cut down on their nicotine intake. 

It can be a little more advanced and take some time to understand what it’s all about. The best way is to learn by doing, and as you will have seen, it doesn’t have to cost a fortune to get a decent setup.

Direct lung vaping is great if you want to blow huge clouds or just want to really enjoy the flavor of some amazing juices. It isn’t stealthy or discreet, but it is a really enjoyable way to vape if you act responsibly.

What is Restricted Direct Lung (RDL) Vaping?

Restricted Direct Lung (usually shortened to RDL) is a vaping style that sits somewhere between MTL and DL. The “Restricted” part of the name refers to the airflow, so it’s like DL but requires less airflow. 

With a RDL vape, you inhale in a similar way to when vaping DL, taking the vapor directly into your lungs. You can produce clouds bigger than with most MTL devices, but thanks to the tighter airflow, you get better flavor and more of a throat hit than with DL. 

What Hardware Do You Need to RDL Vape?

RDL vaping is really ALL about the kit you use and how you use it. It isn’t just a case of changing the way you inhale. Several recent vapes, such as the UWELL Crown D, offer the option for all three vaping styles in one, but you’ll need to configure them in a specific way for RDL. 

Tighter Airflow

Vapes designed for RDL vaping will usually have small airflow holes, similar in size to those seen on most MTL devices. This could be a single tiny hole or an adjustable airflow that can be increased and reduced. 

Smaller Tanks/Pods

This isn’t a hard and fast rule, but it is much more common for vapes that support the RDL style to be small, with a correspondingly small tank or pod. Restricted Direct Lung vaping shouldn’t use up your vape juice much quicker than MTL vaping, so there is generally no need for a huge tank. 

Medium Resistance Coil

One of the keys to RDL vaping is coil resistance. RDL coils usually fall somewhere between high-resistance MTL coils, commonly between 1 and 2ohms, and low-resistance DL coils, which can be as little as 0.15ohm. Coils designed for RDL vaping are usually around 0.7-0.8ohm. 

Small Battery

Again, because vapes designed for RDL are generally small, they rarely have huge batteries. RDL vaping doesn’t require long firing times or very high power settings, so a high-capacity battery isn’t a necessity.

What Ejuice to Use for RDL Vaping?

You can use either high VG or high PG liquids in an RDL vape, or a 50/50 mix. And it works for nic salt liquids and higher nicotine levels than perhaps you would want to use in a true DL vape. 

Because you will be taking more vapor into the lungs when you RDL vape, it is probably best to use liquid with a slightly lower nicotine hit than you might use for MTL. Something around 12-16mg/ml should be good, but you can always experiment to find the sweet spot. 

What are the Advantages to RDL Vaping?

For some vapers, RDL vaping could be the ultimate style. Here’s why:

• Good Clouds

You get to experience the feeling of bigger lungfuls of vapor and decent clouds without the expense, complexity, and low nicotine often associated with an unrestricted DL vape device. 

• Great Flavor

RDL vaping can produce wonderful flavor from your favorite vape juice. Flavors tend to be more intense and often sweeter than even from MTL devices. 

• Flexibility

Several recent vapes offer the ability to switch between MTL and RDL in a single device. Often you only need to switch to the RDL coil, adjust the airflow, and away you go. That allows you to change the vape style at the drop of a hat, without needing to purchase and carry multiple devices. 

• Easy to Use

Although RDL devices might feature adjustable airflow and power settings, they are generally easy to use. Especially compared to a sub-ohm box mod. Many RDL devices use a pod system, with either a fixed or easily replaceable coil, making them no more difficult to use than a basic MTL pod vape. 

• Good Value

RDL vapes are commonly small, low-power devices. That usually means they are cheap to buy and maintain. Because the vaping style doesn’t use huge amounts of vape liquid, you’ll also spend less keeping your tank/pod full. 

Is RDL Right for You?

RDL vaping is a compromise, but a good one. You get some of the best features of MTL, combined with the joy that can come from the full lungs and the bigger clouds associated with DL. 

It could be the perfect choice if you are currently an MTL vaper, and want to see what all the fuss is about with DL without losing the throat hit that many recent ex-smokers enjoy. It could also work well if you are a dedicated sub-ohm vaper who wants a small and simple device to use as a backup for their box mod. 

If you are a new vaper, and looking for a device to get started with, choosing one that offers the option of RDL vaping could be a great way to go. 

Conclusion

What’s the Difference Between Mouth to Lung and Direct Lung Vaping? It would appear quite a lot. Both have their merits and one or two downsides… Ultimately it is a subjective thing as to which one is ‘best’. Our advice would be to give both a go and see which you prefer. There are plenty of cheap inroads into both styles.