Glycogen is stored in the muscle and liver and is used to fuel exercise, feed the brain, nervous system, red blood cells, etc.
Without it, exercise performance is hampered and strength and hypertrophy gains are not as rapid.
We want to have full glycogen stores before we train and also replenish it as fast as possible to be our best for the next training session and to speed up recovery and progress.
Glycogen is created from glucose, fructose and galactose, but all three are converted to glucose-6-phosphate (G6P) before they’re converted to glycogen.
Glucose enters the cells via GLUT4 and is then converted to G6P by hexokinase and glucokinase. Fructose enters the cells via GLUT5 and is converted to fructose-1-phosphate (F1P) by fructokinase and then to G6P through various other enzymes.
After having eaten a meal containing glucose and fructose, the fructose is transported to the liver and the glucose enters the general circulation to refill glycogen stores in the muscles and so on.
1) Fructose and glucose combination
Ingesting a combination of fructose and glucose is superior to replenishing glycogen stores than just fructose or glucose alone.
Firstly, sucrose ingestion alleviates gastrointestinal distress when the ingestion rate approaches or exceeds the capacity for intestinal glucose absorption (~1.2 g/min). Accordingly, when rapid recovery of endogenous glycogen stores is a priority, ingesting glucose-fructose mixtures (or sucrose) at a rate of ≥1.2g/kg/BW/hour can enhance glycogen repletion rates whilst also minimizing gastrointestinal distress.
Secondly, fructose increases glucokinase, thus increasing the glucose uptake into cells which then promotes glycogen synthesis (R).
Thirdly, any leftover glucose and fructose which is not converted to glycogen are then rapidly burned up, because when fructose is ingested together with glucose, the mean oxidation rate of the mixed sugars increases significantly. This is partly due to fructose also increase pyruvate dehydrogenase, which shuttles pyruvate into the mitochondria.
After a workout, ATP is low, which is indicated by an increase in the AMP/ATP ratio and elevated AMPK. The enzyme hexokinase, which converts glucose to G6P, requires ATP and ATP also inhibits the enzyme phosphofructokinase, thus halting glycolysis and promoting glycogen synthesis.
3) Boost GLUT4
GLUT4 is the transporter that allows glucose to enter a cell. If it doesn’t translocate to the membrane of the cell, it will remain inside the cell, thus the glucose will remain high in the blood, as is the case with diabetes. A few other supplements that increase GLUT4 and glucose uptake into cells are Cissus quadrangularis (veldt grape, devil’s backbone and adamant creeper) (R), creatine (R), cinnamon (R), daisy extract (R), epigallocatechin gallate (EGCg) (R), PQQ (R), DHEA (because it converts to DHT; blocking DHT prevents the increase in GLUT4) (R), other DHT boosting supplements and polyphenolic compounds found in fruits.
4) Eat enough carbs
After a workout, glucose uptake into cells is dramatically increased and tapers off after 6 hours. Eating lots of carbs, 1.2-1.5g/kg/BW every 2 hours, will ensure the fastest glycogen replenishment (R).
5) Add protein to your carbs
Protein, such as egg whites, whey and red meat when eaten on its own is very insulinogenic, and eating it with carbs will spike insulin to a greater extent than carbs alone. This effect theoretically will speed up glucose uptake. But research has found that adding protein to your carb meal post-workout only boost glycogen synthesis when carb intake is below 1.2g/kg/BW (R). Eating 1.2g/kg/BW carbs and adding extra protein will not further speed up glycogen synthesis (R). Most people don’t actually eat 1.2g/kg/BW of carbs post-workout unless they use a supplement, and would benefit from adding protein.
Regardless if protein speeds up glycogen synthesis or not, it’s highly advised to consume it post-workout and with every big meal.
6) Ketone ester
The consumption of a ketone ester drink contained 0.573 mL.kg of the ketone ester, (R)-3-
hydroxybutyl (R)-3-hydroxybutyrate post-workout has been found to increase glucose uptake into cells by 32% and promoted greater glycogen synthesis by 50%. The ketone ester increased whole-body glucose uptake from 1.26 to 1.66 g/kg.
The amount of carbs used post-workout (the study used an intravenous method of application and not oral) was to increase whole blood glucose to 10 mM, which is equivalent to carbohydrate feeding of 1.0–1.2g/kg/BW for 4–6 h (R).
More research is needed to see how effective ketone esters will be when carbs are provided orally instead of intravenously.
- Ketone ester – 2.4g per serving, 60 servings
Caffeine has the ability to promote glycogen content regardless if someone has trained or not. This makes it a great supplement to use with the pre-workout meal or shake.
Caffeine can also promote glycogen resynthesis post-workout, but only if carbs are provided at doses less than 1.2g/kg/BW.
Read more on caffeine and glycogen here.
- Caffeine – 200mg per cap, 60 caps
Taurine, a very safe and beneficial amino acid, is also able to enhance glycogen repletion in the muscle post-workout (R). Taurine also increases the amount of glycogen that can be stored in the liver, which also makes it a great supplement to use pre-workout (R).
Read more on taurine here.
- Taurine – 1g per cap, 100 caps. Use 3g pre-workout with a pre-workout meal or shake.
Vanadium is a rare mineral that increases glucose uptake into cells and promotes proper glycogen synthesis in those that are insulin resistant (R). It’s very effective at lowering elevated blood sugar.
- Vanadium – 1mg vanadium per cap, 180 caps. Use 1 cap in the morning with breakfast.