Training · 5 min read ·
What it is, what the research says about strength and muscle after 40, and why the fear about kidneys comes from one test result read out of context.
If you have 30 seconds
- 1Your body makes it and you also find it in meat and fish. It gives ready energy for short, hard efforts.
- 2In the muscle it only works alongside lifting. With strength training, in older people, studies report a little over one kilo more lean mass.
- 3The fear about kidneys comes from a test result read out of context. Anyone with kidney disease should not take it, and the doctor decides.
What does creatine do? It gives your muscle ready energy for short, hard efforts, from a heavy set in the gym to running for a train. It is a substance your body makes on its own, and it is also in meat and fish. In the muscle, it only works alongside lifting.
Three people in the changing room have told you the same thing: take creatine. You are past fifty, you train three times a week between two flights, and you do not know if it is for you.
What does creatine actually do?
Your body makes about one gram a day, and you get another gram from food: red meat has about one gram in every 250 grams. About 95 per cent sits in your muscles, stored as phosphocreatine: when you push at your limit, it gives away part of itself and rebuilds ATP, the fuel of a muscle contraction.
- How many seconds it buys you. The muscle's ready energy lasts about ten seconds of all-out effort. With full stores, studies talk about 13 to 18 seconds.
- What the numbers say. Alongside lifting, studies report 5 to 15 per cent more strength and one to three kilos more lean mass. Over the age of 60, a little over one kilo.
- What it does not do. For stamina and long endurance work there is no proven link. I write about cardio in the article on weights or cardio.
Is creatine bad for your kidneys?
In healthy people, studies find no damage, even after years. In 100 American football players followed for 21 months, kidney function was the same as in the players who did not take it.
Where the fear comes from. Creatine turns into creatinine, and the creatinine on your blood test goes up simply because you have more muscle, eat more protein, or trained hard yesterday. The kidney is fine: in a muscular person, a doctor looks at other markers.
What about bloating? No study confirms water under the skin. Creatine pulls water inside the muscle cell, and there it is an advantage. Under the microscope, the extra kilos were protein, not water.
You build the strength yourself. Creatine gives you a few more repetitions.
Creatine after 40: when should you take it?
There is no best time of day: the effect comes from full stores in the muscle, so in the sources what matters is taking it consistently, rest days included. The amounts they report are 3 to 5 grams a day with plenty of water. A starting load of 20 grams a day for five to seven days is optional, and it upsets the stomach more often.
Will it work for you? Two or three people in ten do not respond: their stores are already full. People who eat little meat and fish respond more. You will know in three months, from the weights you lift.
And your mind? Creatine is also in the brain, and research there is moving: the strongest signals are in people who sleep little and in older people. For that the sources report 5 to 10 grams. A promising direction, with mixed evidence so far.
The order matters. First the lifting, the protein and full nights of sleep; the powder comes after. How many sets you need is in the article on building muscle after 50, and how much protein in the one on protein.
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Test yourself
Your doctor gives you the go-ahead, then a week of travel makes you miss two sessions. What do you do?
If you lift, eat your protein and sleep, creatine is one of the few supplements with research on its side. Start with the question for your doctor, and let your training notebook tell you the rest.
