If you ask average gym goers what the best part of their training session is they’re more than likely tell you the part where it’s over. However the gym rats and people who have been invested in their training for a while will more than likely tell you that it’s the “pump”. What’s a pump you may be thinking to yourself? Well it’s a phenomenon where your muscles seem to grow in real time while training in the gym. You know when you’re training and look in the mirror and it’s almost like you’re as big as you fantasize about being? That’s a pump and it’s a HUGE motivator in the gym. You feel and look as big as what your goals are in the moment, however this typically only lasts for about an hour or so before you feel somewhat deflated. Gym goers chase this pump in the gym, its instant gratification and can help you keep adding in volume when your muscles are already screaming for you to stop. This week we’re going to talk about how glycerol can help you achieve larger and longer lasting pumps in the gym.

What is a Pump?

Dom Mazzetti of BroScience fame has probably put together the best (and funniest) explanation of what a pump is and I’ll post the video below. A pump is the ultimate form of instant gratification in the gym, it’s literally like your muscles are growing before your eyes. You with a pump is the physical embodiment of how you want to look in real life. It’s nature’s way of helping you push past your limits in an effort to grow. You ever done an arm workout and your shirt got tighter on you in the moment? That’s the highly sought after “pump”.

Your training volume is going to dictate whether or not you achieve this pump. Lower volume, higher intensity work more than likely won’t cause this phenomenon to happen for you as you’re not creating enough damage, metabolic and hormonal byproducts to fill your muscle cells with fluid. Higher volume/lower intensity work will lead to getting a pump. If you’ve ever pushed a sled or done a high volume upper body finisher then you’ve no doubt felt this.

From a scientific standpoint there’s quite a bit going on when you achieve a pump in the gym. To start, the term pump is broscience slang and the actual name for it is transient hypertrophy. Transient means temporary while hypertrophy is the growth of the muscle cell so this term literally means temporary growth of the muscle. Another name often used for this phenomenon is hyperemia, which means excess blood in the vessels supplying a muscle or organ in the body. When you get a pump, you have a lot more blood in the cell making it appear larger.

During training the working muscles receive as much as 4 times the amount of blood they would typically get throughout normal function. This is to ensure the muscle can accomplish the task at hand, and we don’t end up with dead protein structures breaking off and clogging the kidneys. The muscles need oxygen and nutrients to continue to function, and this increased amount of blood allows for enough oxygen and nutrients to be delivered to the working structures in the muscle cell. Blood is a big part of the pump, but there’s more to it.

There’s also a build up of metabolic and hormonal byproducts in the cell when we get a pump. Creating energy inside the cell requires substrates to break and build and break and build, etc. These processes create leftover substrates or byproducts. Think of this like cooking bacon in a pan. You throw the bacon in the pan and cook it, and when it’s finished cooking there’s grease left over in the pan. Now if you’re like most people you’re not gonna drink that grease and instead find a way to dispose of it. Heat + raw bacon= cooked bacon and grease. You have what you intended to make and then some left over stuff that you’re hopefully not gonna dump down your drain. This is how the processes in your muscles work when you’re training. Those byproducts have to be disposed of, but the process takes time and in the moment it hangs out in the muscle. The most notable one being lactic acid.

So now your muscles have 4 times the amount of blood in them and in addition to that you’ve got this metabolic byproducts left over from muscle contractions. Lactic acid is a byproduct of these processes and while it’s hanging out in the muscle waiting to be transported to the liver to be broken down into glucose it actually helps to increase intracellular water while also decreasing the osmotic resistance of red blood cells. Lactic acid actually helps keep your pump alive while you’re training in the gym, crazy huh?

So, in the easiest to understand terms the pump we get in the gym is mostly a collection of blood and water in the muscle cell.

How Do I Get This Pump?

High volume (12-20 reps), moderate intensity (50-70% of your 1RM) work in the gym is the best way to achieve transient hypertrophy. A moderate intensity will allow you to create enough tension to create damage in the muscle cell’s protein structures thus leading to more blood flow while also allowing for higher volume work. Too much intensity won’t allow for adequate volume, too little intensity won’t create enough damage, so stick to 50-70% of your 1RM if you’re looking to maximize your pump. Higher volume work facilitates more damage (if the intensity is right). If you need to see this in real time on your next trip to the gym work up to your 1RM. More than likely you don’t have that skin bursting feeling in your muscles. After you’ve worked up to your 1RM back down to 50% and hit it to failure. Now how do you feel? Probably like your pecs, arms and shoulders are about to explode.

Tons of supplement companies have also created a wide array of “pre-workout” supplements geared to both give you energy and to help amplify your pump. Some even stick stuff they shouldn’t into their products most notably DMAA which has since been banned for its cocaine like effects. They fill these products with caffeine, citruline malate, creatine, arginine, carnitine, and others with or without any real data to support putting them into their products. They contend that their products can amplify your pump due to increases in nitric oxide production in your blood leading to more dilated blood vessels thus more blood to the working muscles. While I swear by arginine due to my own personal anecdotal evidence, there’s actually no data to support that it works and plenty to show that it doesn’t. Glycerol is a substance that actually doesn’t get used very often in these supplements which is odd because there’s solid evidence that it works and it’s incredibly cheap. We’ll talk more about that in the next section.

What is Glycerol?

Now you know what a pump is and how to achieve it but how does glycerol work to help amplify your pump? To figure that out we first need to talk about what glycerol is. Glycerol, also known as glycerin, is the backbone of the majority of the fats you consume in your diet: triglycerides. Triglycerides are three fatty acids held together by a glycerol backbone. The glycerol doesn’t operate in the same way fats do though, when these triglycerides are broken down in the body the glycerol heads to the liver to be converted to glucose to be used as fuel instead of being stored in fat cells.

You may have actually heard the word glycerin before as it’s used as a laxative and also as an emollient. It actually has a sweet taste and is sometimes used as a sugar replacement due to the fact that it has no effect on blood glucose levels. In the 90’s the band Bush actually sang about glycerin and its effects helping make skin smooth. It was also the prime ingredient (from liposuction derived fat) in the soap made by Project Mayhem in the movie Fight Club. It’s used in the making of explosives and even antifreeze. But one of its not so well known uses is as a supplement for hydration. Its usefulness as a super hydrator lies in its strong osmotic properties that help pull water out of the subcutaneous layer of the skin and into the muscle cell.

Side story: back in 2010 I was working at a facility doing combine prep and we had an athlete who had a spiral fracture of his fibula who, for some totally unknown reason, had a plate and screws put into this non weight bearing bone. He couldn't train hard enough around this injury to really put on the mass that teams wanted him to. So we thought about it and decided our best course of action was to have him take about 40 grams of glycerin the morning of his weigh in and drink as much water as possible and do a banded workout to help increase his ability to hold water in his muscle cells. He ended up weighing 15lbs heavier and testing 2% lower in his body fat than he did just a few days prior at our facility. Glycerin REALLY works to help hydrate the cell and pull water our of the skin which lead to both outcomes. While I don’t recommend this strategy for day to day usage, when there’s millions of dollars on the table I believe it’s acceptable.

Glycerol has calories just like carbohydrates. There’s 4 calories per gram of glycerol, however due to the fact that it heads to the liver to be converted to glucose it has no impact on blood glucose levels and won’t create an insulin spike with its use. It’s used in protein bars as a sugar replacement and it often used in protein powders to box in proteins and allow for a slower release of amino acids once consumed. Glycerol helps the body hold water in the muscle cell throughout training sessions amplifying your pump and this extra hydration in the cell allows for a more sustained and prolonged effort leading to an even bigger pump!

If you really want to get more bang for your buck with your pre-workout supplementation then add creatine into the mix as well. A study published back in 2007 out of Scotland found that participants who took both creatine and glycerol for a seven day period had roughly 40% more body fluid than those who just took creatine, and nearly 50% more body fluid than those who took only glycerol. These two substances used together can really help to hydrate the muscle leading to better pumps and performance both in the gym and on the field of play.

Is Glycerol Safe?

YES! Although it’s probably strange to think about putting something into your body that is also used in explosives and soap, it’s perfectly healthy to add glycerol to your pre-workout supplement regimen. It’s not only a great thing to add before lifting, but also it can be great for sports performance. More hydration is going to mean better sustained efforts on the field of play, and better recovery. When we’re as little as 2-3% dehydrated our body actually shuts off anabolism which is the part of our metabolism that builds and repairs. You’ve probably heard the word anabolic before when it’s used to describe anabolic-androgenic steroids. The reason they’re called anabolic steroids is because of their building properties, and their ability to keep the body in an anabolic state. Anabolic is just a descriptive word for the body’s anabolism processes. There’s more than likely a point of diminishing returns, however rest assured that your pre-workout supplements that contain glycerol only have 10 grams at most.

How Much Should I Take?

There’s no real data for how much is necessary to achieve the benefits of glycerol use. This supplement hasn’t been studied in the same way that creatine, arginine, leucine, etc have been so there’s no standard when it comes to its usage. The best information we currently have says you’re probably safe somewhere between 10 and 40 grams roughly an hour before training and into your training session. While that’s a pretty big range, my advice would be to start at 10 grams and see how you respond. If you’re not getting the desired results, slowly add more. If you want an unreal pump in the gym try to do the following:

• Keep your training volume high and your intensity moderate. 12-20 reps at 50-70% of your 1RM.

• Take a pre-workout supplement and hour prior to training consisting of

  • 10-40 grams glycerol

  • 5 grams of creatine

  • 3-5 grams of arginine

  • 1/2 teaspoon of salt

  • Optional: 75-100mg of caffeine

• Stay hydrated and have water on you throughout the day.

Glycerol is safe and effective to use at all ages. If you’re someone who wants to stay away from stimulants when training then it’s a great addition to your pre-workout supplementation that will still help give you motivation through its skin stretching pumps without leaving you jittery.