Glycogen
- Energy storage
- Training
- Metabolism
By Mag. Christian Schönbauer, founder of Hardgainer Performance Nutrition®. Training since 1999, started under 50 kg.
Glycogen is the storage form of glucose in muscle and liver, your fast-access energy store for hard sets. For a hardgainer (hard gainer), glycogen is not an isolated pump factor but a lever in the system of calorie balance, carbohydrates and training volume.
Note
This page gives you context and practice, not medical or individual nutrition advice. If you have diabetes or another metabolic condition, please check your carbohydrate intake with a doctor.
What is glycogen? The definition in 20 seconds
Glycogen is made of many linked glucose molecules and is stored mainly in skeletal muscle and liver. In muscle it fuels hard sets: through glycolysis it keeps supplying ATP when a set runs longer. Your liver uses its glycogen to keep blood sugar stable between meals and overnight. The breakdown there is driven by glucagon.
- Fuel for volume: Strength training drains muscle stores measurably too. The more hard sets, the more your training draws on them.
- Refilled through carbohydrates: Insulin shuttles the glucose from your food into your cells and refills your glycogen stores.
- For hardgainers this means: Lots of daily movement, lots of volume and few carbs are a bad combination. Many notice it first as sluggish sessions and stalling performance.
The anchors in the system: TDEE, lean surplus and the Metabolism System.
Glycogen: what you control and what you don't
You cannot measure your glycogen stores in daily life, and you cannot turn them up on purpose. How much you burn in training also varies a lot from person to person. What you can control is the frame in which your stores fill up.
- Calories first: Without a surplus every store stays tight. 150 to 250 kcal a day above maintenance is our deliberately cautious starting value.
- Carbs fill the rest: Once protein and fat are set, carbohydrates cover the rest of your calorie target. Going low-carb makes gaining harder than it needs to be.
- Around training: Carbs before and after training refill your stores. Right after training the refill runs faster, but the amount over the day still decides.
- Training days and rest days: Plan more carbs on training days and a little less on rest days. As long as your weekly balance and your rate of gain fit.
Practice: the 14-day check
- Day 0, set your base: Lock in your calorie corridor, fix protein and fat, work out carbs as a daily number. Plan one meal before and one after training.
- Document daily: Morning bodyweight, carb target hit yes or no, load and reps on your main lifts and steps as your measure for NEAT. Build weekly averages. How much your steps burn is shown by the NEAT Calculator.
- Day 14, check the trend: Sessions sluggish, performance dropping, weight flat? Raise carbs on training days and check your daily movement. Weight jumping after carb-heavy days? Judge the weekly average, not the single day.
You do not measure glycogen directly. You see it in your training log and in your weekly average.
Common misconceptions
- “Carbs make you fat.” Whether you gain fat is decided by the size of your surplus, not by the macronutrient itself. When you are gaining, carbs are your fuel.
- “The jump on the scale after a carb day is fat.” Usually not. Glycogen is stored together with water, which is why your weight swings from day to day. For your trend, the weekly average counts.
- “Full stores mean more muscle.” Full stores make the muscle look fuller, and many get a better muscle pump. That is volume inside the muscle, not new tissue. Growth comes from training and a surplus over weeks.
- “Without a shake right after training it is all lost.” Carbs right after training speed up the refill in the first hours. If you eat enough over the day, your normal meals fill the stores too.
Every cardio session eats into your muscle growth. If you want to gain, you drop cardio completely.
Cardio burns energy and draws on your glycogen stores. It only becomes a problem when cardio volume, calories and strength training do not fit together. Plan cardio into your calories, and your surplus and stores stay stable.
Common questions
What is glycogen and why does it matter for hardgainers?
Glycogen is the storage form of glucose in muscle and liver. In muscle it fuels hard sets. It matters for hardgainers because lots of movement, lots of volume and too few carbs drain the stores and drag down training performance.
Do I need to eat carbohydrates before training?
Not necessarily right before. What matters more is eating enough carbs over the day. Many do well with a normal meal a few hours before, or a small snack if the last meal was a while ago.
Can hardgainers follow a low-carb diet?
Possible, but rarely the best choice for gaining. With high training volume and high NEAT your stores run low easily. That costs performance and makes your surplus harder to hit.
2 more questionsShow less
How long does it take to replenish glycogen stores?
With carbs right after training, the refill runs clearly faster in the first 2 hours than without. How long a full refill takes depends on amount and training. If you eat enough between two sessions, you rarely need to worry about timing.
Does cardio drain my glycogen stores?
Yes, cardio draws on your stores, and how much varies a lot between people. Plan cardio into your calories and carbs, and it will not slow your gains.
From term to practice: your tools
Full stores need a clear frame. These three tools give you the numbers for your 14-day check.
See all Hardgainer Tools. If you want more out of your numbers, go with Hardgainer Pro.
What the research says
Three papers behind the claims on this page
Glycogen is fuel that drains and refills. These three papers are behind the claims above.
- With 1.5 g of carbohydrate per kg right after and one hour after strength training, glycogen resynthesis ran significantly faster in the first 2 hours than with water. 8 men not currently lifting, fasted, an average of 8.8 sets of 6 single-leg knee extensions at 70 percent of 1RM. Muscle glycogen dropped by 40.6 to 44.3 mmol per kg. Pascoe et al., Medicine and Science in Sports and Exercise, 1993
- How fast muscle glycogen is broken down during exercise depends on intensity, duration, training status and carbohydrate availability. A review focused on endurance sport. It also describes glycogen as a regulator of signalling pathways in the muscle cell, not just a fuel store. Hearris et al., Nutrients, 2018
- After 30 minutes of cycling at 50 to 80 percent of maximal oxygen uptake, the change in muscle glycogen ranged from plus 58 to minus 200 mmol per kg dry muscle. 19 participants, 15 men and 4 women. Use was not significantly related to relative intensity, whether based on oxygen uptake or lactate threshold. In other words, it is highly individual. McLellan and Jacobs, International Journal of Sports Medicine, 1991
What the studies do not cover
The strength training study had only 8 participants and a single exercise. McLellan and Jacobs studied cycling, the Hearris review mainly endurance sport. None of the three papers measured muscle growth.
Your takeaway: glycogen is fuel for your volume. A clear surplus with enough carbs around training keeps your stores full.
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Reading & Resources
The terms directly around glycogen and the pillars next to it.
Content here is general practice guidance and does not replace individual medical or nutritional advice.
