How Muscle Soaks Up Creatine
Creatine uptake in isolated soleus muscle: kinetics and dependence on sodium, but not on insulin.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Muscle cells use sodium to pull creatine inside, like a pump. A chemical that looks like creatine blocks this pump. Insulin doesn't help in a dish. Type I muscle (soleus) grabs creatine better than type II at low levels, but both fill up the same when there's lots.
Surprising Findings
Insulin had no effect on creatine uptake in vitro, despite decades of advice to pair creatine with carbs for insulin spikes.
Most fitness advice claims insulin opens the door for creatine—this study says the door doesn’t need insulin at all in this model.
Practical Takeaways
If you’re taking creatine, focus on consistent daily dosing rather than pairing it with high-sugar drinks to spike insulin.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Muscle cells use sodium to pull creatine inside, like a pump. A chemical that looks like creatine blocks this pump. Insulin doesn't help in a dish. Type I muscle (soleus) grabs creatine better than type II at low levels, but both fill up the same when there's lots.
Surprising Findings
Insulin had no effect on creatine uptake in vitro, despite decades of advice to pair creatine with carbs for insulin spikes.
Most fitness advice claims insulin opens the door for creatine—this study says the door doesn’t need insulin at all in this model.
Practical Takeaways
If you’re taking creatine, focus on consistent daily dosing rather than pairing it with high-sugar drinks to spike insulin.
Publication
Journal
Acta physiologica Scandinavica
Year
1999
Authors
C. A. Willott, M. E. Young, B. Leighton, G. Kemp, E. Boehm, G. Radda, K. Clarke
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Claims (7)
The soleus muscle, which is used for standing and walking, is better at grabbing creatine from the blood when there’s not much of it around than the fast-twitch muscles in your leg, like the extensor digitorum longus.
In a lab dish, adding insulin doesn’t make rat leg muscle cells take up more or less creatine, even when the insulin level is normal for a living body.
A chemical that looks like creatine can block muscle cells from taking in creatine — in rat muscle tests, it stopped 82% of the creatine from getting in when used at a certain strength, which means it might be pretending to be creatine to get in first.
Scientists found that rat leg muscle cells absorb creatine at a specific speed and capacity—like a sponge that can only soak up so much water before it’s full.
When scientists lowered the sodium levels around rat muscle cells, the cells absorbed much less creatine—showing that sodium is needed for creatine to get inside these muscle cells.