Explained: MTL (Mouth to Lung), RDL (Restricted Direct Lung) and DTL (Direct to Lung) Vaping Types
Those of us lucky enough to have been introduced to the world of vaping at its inception over a decade ago will know what I mean when I say it’s currently one of the most dynamic and vibrant industries to be a part of.
That’s in any capacity, whether private or professional. As vaping has metamorphosed from being a simple e-cigarette style tobacco replacement, into a hobby, state of mind and culture with more devices and facets than we can count…our understanding of things has changed.
I, as a female, now know all about Ohms Law, basic electronic engineering and a host of other things that I never quite grasped or thought I would ever grasp until I took a shine to vaping.
Here I am, completely geeking out on something that used to be a bad habit (my insatiable need to inhale things!).
Another thing that’s grown is my vocabulary: with a bunch of new terms and an ever expanding lingo, acronyms especially, which surely need to start making their way into dictionaries ASAP!
Two such acronyms, which may leave newbies asking ‘WTF?’ after reading a standard vaping article nowadays, are:
- MTL – ’Mouth To Lung’
- DTL – ‘Direct To Lung’ (Sometimes referred to as ‘Straight to Lung’ or ‘Direct Lung’)
- RDTL / RDL – ‘Restricted Direct To Lung’ – In between the above two styles
These terms describe your vaping style, the way you inhale or draw on your product and…with tens of new vaping products hitting stores on a daily basis: trust me, a variety of distinct vaping styles exist.
You need to know and understand both these inhalation styles if you want to use your device efficiently and also if you want to know which device you should be using.
Whether you vape disposable e cigs, vape pens, e-hookahs, dry-herb devices, sub-Ohm tanks, squonk/drip, build your own coils and RDAs or cloud chase.
One thing you need to know about if you’re going to be calling yourself a vaper (also, to avoid the scorn of somewhat cliquish pros) is the difference between MTL and DTL vaping.
This should include:
- How to actually vape MTL or DTL
- Who does which and why?
- How your device resistance, wattage, airflow and your e-liquid composition affect your MTL or DTL experience.
- As well as any tips and tricks which may help to enhance your vaping experience.
So, vent those OMGs, LMAOs, take a nice, solid DTL or MTL toke and sit back. Let’s get to work!
Vaping Style: Mouth To Lung (MTL)
How Do You Vape MTL?
It may sound like such an overly simple question but it’s something that needs asking.
Vaping is different to smoking for many reasons but the actual way you vape is also different. MTL Vaping is ‘kind of like’ cigarette smoking but with a slight difference.
Simple steps on how you vape mouth to lung.
- Take a smooth draw of vapour into the mouth. (Don’t take short, sharp drags like you would on a cigarette) A slightly longer draw is needed.
- Once vapour is in the mouth inhale to lungs drawing air in at the same time. Also known as “Taking back” or almost “Swallowing” the vapour.
Who Does It?
Indeed, for some of us, it’s been a while since we saw the sense in a mouth to lung hit…for others, the concept of a direct to lung hit is completely foreign.
Smokers do it, recent tobacco quitters do it, newbies do it, plus-ohm device users do it and to be honest…people who don’t (yet) necessarily see vaping as a freakin’ sport like some of us, they do it too.
Editor (Jonny): I do it too…90% of the time 🙂
Why Vape MTL?
For some it’s a case of having no interest in spewing out huge clouds of vapour. It’s for those that want nicotine delivered by something as similar to the experience of smoking as they can get.
It is pretty natural for a smoker or recently ex-smoker to vape MTL and often they crave the throat hit they would get from a cigarette which is also part of the MTL experience.
It stands to reason, you can only fit so much breath in your mouth and therefore the MTL method won’t have you seeing substantial vapour production at all.
That said, it has its applications: such as when you’re trying out juice flavours and want to get a real sense of the flavour profile and mouth feel.
Also, when you’re trapped in a high strung crowd and in need of a soul-fix…the so called ‘stealth vape’ involves not only the clenched fist (to hide your device) but also the infamous MTL hit.
If you need to go super stealthy keep the inhaled vapour in your lungs for an extra few seconds: exhale the near invisible plumes and savour the angst!
Others just prefer it as it can also be a more economical way of vaping. MTL tanks use less e liquid than a sub ohm tank. The latter of which is predominantly used for direct to lung inhales.
Many simply have no option due to years of smoking and the state of their lungs. They struggle taking a full on direct to lung hit.
Nicotine, PG and VG For MTL Vaping
Because you are essentially consuming something, you should be aware of your e-juice composition.
Which Nicotine Strength Is Best For Mouth to Lung Vaping?
MTL differs massively from DTL in that you can afford to use a slightly higher nicotine content without making yourself ill due to the fact you will be using higher resistance coils and lower power outputs.
Personally, I use either 0mg or 3mg. Other reviewers here use 6mg, 12mg or 20mg. It will ultimately depend on your needs.
If you’re a recent quitter you will likely want to opt for a nicotine strength between 12mg and 20mg.
However to some people a standard (freebase) nicotine of a high strength will be a bit harsh. If you find you want strong nicotine but it is burning your throat out consider Nic Salt e-liquids which are slightly smoother at higher nicotine concentrations. More importantly nicotine salts also absorb into the bloodstream quicker and more effectively than standard (freebase) e-liquid giving you a more satisfying nicotine hit.
If you are a new vaper that has moved/or moving from cigarettes then I would recommend nic salt as your first port of call.
You can check out our guide to nicotine salt e-liquids here.
If you try a juice and you don’t feel like it’s controlling your cravings or it feels slightly too much then change your strength up or down accordingly. It can take a little bit of experimenting at first.
TIP: If you have never vaped and your budget allows, buy both a 12mg and 18mg e liquid at the same time. If one isn’t for you then you don’t have to wait days for your new juice to be delivered.
So…if you’re vaping for a nicotine fix, MTL is for you.
Which PG/VG Ratio Is Best For MTL Vapers
This section needs paying attention to. Choosing the wrong PG/VG ratio for first time users can make or break an experience. PG and VG are two of the main ingredients in e liquid.
- PG – Propylene Glycol
- VG – Vegetable Glycerin
As far as PG and VG go, the devices which support MTL hits are generally only suited to a higher PG content.
I have seen many a time new vapers buying 80% and 90% VG juices for their new vape pen kits or pod mods and then blaming the devices for continual dry hitting.
It’s generally not the devices fault, as VG is a thicker consistency (PG is thinner) that can have trouble wicking in the smaller MTL coils. PG is also known to be a good flavour carrier.
Also, because this method is considered as a suitable smoking replacement…the throat hit from PG e-liquid will probably seem more satisfactory to this type of vaper.
A higher nicotine strength I’ve found can also be a main contributor to increased throat hit.
Recommended PG/VG Ratios for Mouth To Lung Devices
- 50PG/50VG – Good throat hit – OK vapour production
- 60VG/40PG – A smoother vape – Vapour production better
- 70VG/30PG – Some of the more recent MTL devices vape well with this ratio but double check first!
- Nicotine Salt e-Liquids are also a superb (and recommended) option for new vapers. These are generally a 50/50 ratio so perfect that mouth to lung vape experience.
Your vape tanks airflow is a deciding factor in whether you’re going to be direct inhaling or mouth-to-lung inhaling.
A tight airflow will mean that on a MTL hit, by the time you inhale…your lungs are in need of oxygen and will welcome any they can get (an easy hit, in other words). A tight airflow also provides a warmer vape.
The main difference you will notice between a MTL tank and a DTL tank is the mouthpiece. On the MTL tank the mouthpiece will be a lot narrower to mimic the act of smoking.
Whereas the mouthpiece on the DTL tank will be a lot wider allowing for more vapour to be inhaled.
Try a MTL hit with open airflow on a sub-Ohm tank and you’ll get a mouthful of heat with almost no vapour, you’ll feel like something’s wrong and when you go to inhale, either a lungful of pure heat or nada.
Your inhale won’t be satisfying any need to breathe in at last…it’ll feel like a lungful of ‘what the hell’.
Check out our top rated mouth to lung vape tanks here.
Coil Resistance For MTL Vaping
- Higher resistance coil (MTL) = Anything above 1.0 Ohm
- Lower resistance coil (DTL / Sub Ohm) = Anything below 1.0 Ohm
Lower resistance coils made for MTL vaping are made with thinner wires that don’t allow as much power/wattage to be fed to the coil than a lower resistance (DTL) coil would.
Low resistance coils are made with Thicker wire.
For this reason MTL vaping is best suited for use on the lower wattage scale on box mods or vape pens. I have vaped anywhere between 11W and 20W with MTL vape tanks with a resistance (ohms) above 1.0 Ohm.
It’s likely, if starting out and buying a vape pen style e cig or pod vape, that the kit you choose will be fixed wattage and will be set to work perfectly with the matching tank/coil in the kit.
Fixed wattage devices provide a very hands off vaping experience and are a great starting point. So don’t stress too much about having to learn that extra step of a variable wattage device 🙂
If it does have variable wattage, no problem. Just start low and work your way up until you find the right wattage for you.
But I’ve Seen MTL Tanks With ‘Sub Ohm Coils?
This is where things can get a bit confusing.
You may see certain MTL tanks have coils rated anything from 0.3-0.9ohm. ‘Well these are sub ohm tanks’ I hear you say!
Well yeah they are ‘sub ohm’ coils.. but the famous Thai phrase “Same same but different” rings true here.
Tanks that are made specifically for mouth to lung vaping will have a lot smaller coils with small juice holes, these holes restrict the amount of vape juice that feeds through to the coil.
True sub ohm tanks may also have the same coil ratings but these tend to have big beefy coils with huge holes on the side to let plenty of vape juice soak into the coils.
What Coil Resistance (Ohms) Should I Use For Mouth To Lung (MTL) Vaping?
- For MTL, coils range from 0.6Ohm-2.8Ohm.
- The most common coils for MTL vaping are 0.6Ohm and 1.8Ohm.
RDA’s can also provide a stellar MTL experience, some of the best in fact. But as this is a guide aimed at new vapers we won’t go into that here as it’s an advanced form of vaping that takes a lot more learning and time.
You can learn about rebuildables here if you have an inner ‘DIY’er’ trying to break free.
What is RDL?
To be honest, RDL is basically classed as the bridge between DTL and MTL vaping. It has more in common with DTL with a slightly more restricted airflow.
A lot of pod kits in particular with adjustable airflow have the option for this style of vaping.
It is particularly suited for kits which are not able to provide the super high outputs for full DTL vaping. Basically a “DTL Lite” kind of experience.
For instance a 40W mod which would be struggling to power a DTL 0.15ohm coil, would instead offer perhaps an 0.4ohm coil with an option for a RDL airflow.
Also if a kit provides an MTL adjustable airflow, allowing slightly more airflow provides the facility for a RDL vape without having to redesign the tank / pod for a full DTL set up.
Of course if you have a tank with an airflow adjustment which covers MTL and DTL you will find the mid setting should be just right for RDL.
Why Vape RDL?
Well as mentioned above it means that you should be able to use a wider range of kits.
Any kit with adjustable airflow could be suitable for RDL vaping! If you buy an MTL kit – there is a good chance that the wide open airflow setting will offer an RDL sensation. If you buy a DTL device – close off the airflow to get near to a RDL setting.
Designing devices which are able to provide a satisfying MTL and DTL vape is pretty difficult. Many manufacturers may claim this to be the case, but often one style suffers.
But adding the RDL option means it is not a huge jump to provide 2 satisfying vaping styles on one device. Even some of the same coils are able to cater to RDL and another style without huge changes to the device other than providing a slightly wider range to the airflow.
This way a pod kit for instance designed for one vaping style can be actually a bit more versatile by adding RDL to perhaps attract more vapers who will enjoy the middle ground.
Vaping Style: Direct To Lung (DTL)
How Do You Vape DTL?
This is the polar opposite to the MTL style of vaping. It can take some getting used to as it will be a completely foreign concept for most.
Simple Steps on How You Vape Direct to Lung Style.
- Draw slow and steady directly into your lungs.
- A drag DTL style can be 3-5 seconds or more.
- The key is not to take sharp drags.. Smooth, steady motion is the key.
- Once it reaches your lungs exhale those clouds of vapour.
Who does it?
Well, if you fancy a full, creamy and thick clouds and a solid lungful of tasty vapour…then you’re going to need to hit that fog straight into your lungs: that’s the only way to fill your lungs to near capacity.
Only with a Direct To Lung hit can you enjoy the scope of a high wattage mods and sub-Ohm tanks; see any real vapour production; perform tricks or cloud chase and really experience the flavour profile of a juice on exhale.
Direct to lung vaping is for lovers of vaping who’ve completely overcome their cigarette craving, it’s for vapers, like me, who love the magic of exhaling beautiful, rich clouds and messing around with high powered box mods, vape tanks and gear.
Why Vape DTL?
Your first attempt will be a shock to your lungs but over time, if you start with a low wattage and tight airflow and slowly open up…your lungs will learn to love it.
It’s a different ballgame, my friends, you will feel like a weather controlling, invincible superhero most of the time: young folk will admire you, old folk will look at you strangely and you’ll annoy the crap out of your other half when binge watching your favourite box set.
Either way, the devices that go along with using this method will bring you joy; the opportunities for sampling new and scrumptious flavours will turn you into a kid-in-a-candy-store.
Vape-voice (when you talk with a lungful) and those exhibition-worthy Instagram vapour pics you’re now capable of capturing will keep you forever young at heart and you’ll soon forget the old days of nasty tobacco smoking.
As you may be able to tell, I’m am a fan of the plume producing, cumulonimbus joy that is the DTL vape hit…and I thank you, vape gods!
Nicotine, PG and VG For DTL Vaping
Here’s where you need to keep your head screwed on…vaping sub-Ohm with a DTL device, while using a high nicotine count e-juice will make make you feel like you’ve just had 6 straight shots of espresso.
Which Nicotine Strength Is Best For Direct to Lung Vaping?
I recommend 6mg or less for DTL hitters and that’s that. The majority will use 3mg but that is of course for you to choose.
Just remember, the higher your nic strength, especially in a sub ohm device, the harsher the throat hit and bigger nicotine hit.
Which PG/VG Ratio Is Best For DTL Vapers?
As far as PG and VG go…DTL devices are more suited to a higher VG that produces a far more satisfying, smooth and full vapour.
VG will be easier on your lungs, completely easy, in my experience. Vape smart and enjoy vaping for what it is. For me it’s a tastier and far more entertaining experience than smoking will ever be!
Recommended PG/VG Ratios for Direct To Lung Devices
The below is a general guideline. A lot of the experiences you have with flavour and vapour production can also depend on the specific e-liquid brand you choose.
- 60VG/40PG – Very good flavour, decent cloud production and a hint of throat hit.
- 70VG/30PG – One of the most popular blends for sub ohm/DTL vapes. Good flavour, plenty of clouds and smooth throat hit.
- 80VG/20PG – Good flavour, dense clouds and silky smooth throat hit.
- 90VG/10PG – Good flavour, even denser clouds and smooth on the throat.
- 100% VG – Pure clouds and super smooth. This is also used by vapers that are sensitive to PG.
Tanks and Wicking High VG Juices
It all sounds so simple so far hey? Well, it is and it isn’t!
If going for a 80%+ VG juice you need to keep in mind the tank you are using.
This will make a huge difference. Not all sub ohm tanks coils are capable of wicking juices in the 80%+ range.
This is down to high VG juices being thicker in viscosity, this in turn takes time to soak through the cotton.
If your tank isn’t very efficient at wicking high VG juices you will likely get dry hits, especially chain vapers out there, as you are vaping faster than the juice takes to soak into the cotton.
Check around and do a google search to see how your tank fares. Try this Google search ‘Does tank name wick high VG juices’, obviously replacing tank name with the tank you have or are looking at. You should get your answer.
If not ask your vendor or send an email to the manufacturer. Or search this site (In the header) to see if we have reviewed the tank you are looking to buy.
To be on the safe side, try and stick to a max 70VG/30PG for your first ‘sub ohm e-juice’. Most sub ohm tanks can handle that ratio just fine.
When vaping you will have the chance (in most tanks) to change your ‘airflow’. This is done through a ring on the top or bottom of the tank and be fully opened or closed.
An open airflow means that whilst you inhale your vapour, more air is allowed to flow through the tank and into your lungs unrestricted. You’ll notice that as you open it up, your hits will become longer and easier and your cloud production, magnificent.
Closing up the airflow will result in a more intense, warmer and slightly more restricted vape. This can also help bump up that flavour a touch.
Remember, if you’re inclined to draw in slowly and aren’t a cloud freak like me, you should use a medium airflow so that the vapour doesn’t become too hot for your lungs.
As with anything vape related, it’s all about testing and finding your sweet spot.
Coil Resistance For DTL Vaping
- Lower resistance coil (DTL / Sub Ohm) = Anything below 1.0 Ohm
- Higher resistance coil (MTL) = Anything above 1.0 Ohm
A lower resistance coil/tank means you’ll be able to operate it at a higher wattage. Lower resistance coils are what we need when sub ohm/Direct to Lung vaping.
Lower resistance coils are made with thicker wires that allow more power/wattage to be fed to the coil than a higher resistance coil would.
High resistance coils are made with thinner wire.
So, maintaining a higher temperature for longer and sustaining your inhale until your lungs are full (that’s what you need for a DTL hit) without damaging your device so kapow! Cloud chasing 101 here we come.
What Coil Resistance (Ohms) Should I Use For Direct To Lung / Sub Ohm Vaping?
- Sub ohm coils for DTL / sub ohm vaping range from 0.1-0.9Ohm. Stock coils that is.
- The most commonly used is 0.3Ohm – 0.6Ohm
The MTL vs DTL Vaping Verdict
Now that you have two more acronyms to blab, you can set about exploring new devices, forgetting smoking forever and all-round living life, enjoy and please, vape safe!
Whatever method of vaping you choose will be down to your personal preference. Just remember any type of vaping is good if it helps make the switch. Whether that’s a cig-a-like or building your own coils.
Hopefully you are a little clearer on what the difference between mouth to lung and direct to lung vaping styles are.
Of course, any questions please ask away in the comments below!