Are antioxidants bad for mucle growth?

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Antioxidants are known as healthy nutrients. But getting too many antioxidants can have a negative effect, including for muscle growth. How is that exactly?


Antioxidants are – the name says it all – substances that prevent oxidation. Simply put, oxidation is the reaction with oxygen and occurs in both living and non-living nature. The rusting of iron is a good example of oxidation. The iron rusts because it reacts with oxygen, or oxidizes.

Oxidation also takes place in the human body. An example of oxidation in the body is the oxidation of glucose, or the conversion of carbohydrates (sugars) from your diet into energy.

Oxidation is essential for sustaining life.


However, the oxidation process can also release harmful substances, the so-called free radicals. These are aggressive substances that can cause damage to cells and tissues, the so-called oxidative stress. Oxidative stress occurs when there are too many free radicals in the body, or when these substances are located in unwanted places in the body.

There are strong indications that free radicals play a (important) role in the development of diseases such as cancer and cardiovascular disorders and may also play a role in age-related diseases such as Alzheimer’s, Parkinson’s disease, diabetes and various neuro(muscular) disorders.


‘Antioxidants’ is an umbrella term for various vitamins (including vitamins A, C and E), trace elements (copper, manganese, selenium and zinc) and bioactive substances with an antioxidant effect (carotenoids, flavonoids and coenzyme Q10).

Antioxidants are mainly found in fruit and vegetables – especially berries – but also in plant-based drinks such as coffee, tea and wine. Eating berries is therefore a good way to provide (part of) your antioxidants. Just like drinking tea and coffee (moderately).

Antioxidants fight free radicals and can thus reduce oxidative stress. That is why they are considered ‘good’. Excessive oxidative stress can cause tissue damage and is therefore often labeled as ‘bad’. However, this is a bit oversimplified, as we shall see below.


Exercise increases oxidative stress in muscles. This causes the muscle to adapt to exercise, suggesting that some level of oxidative stress is beneficial. Therefore, you could speculate that intake with antioxidants should be avoided around (strength) training, especially when it comes to supplements.

Norwegian study confirms this. It was investigated whether a high-dose antioxidant supplement affects the increase in lean body mass during twelve weeks of strength training in older adults. One group received vitamins C (500 mg) and E (117.5 mg) before and after each workout, while the other group received a placebo supplement. The group that received the antioxidant supplement showed a lower increase in lean body mass compared to the placebo group (+0.87 versus +2.19 kg).

However, this does not mean that antioxidants should be avoided completely. The doses of vitamins C and E in this study were very high. For example, oranges are known for their high vitamin C content. You would have to eat ten oranges before exercise and another ten after exercise to get the same amount of vitamin C in this study. That is why it seems unnecessary to avoid antioxidants from regular food, concludes researcher Jorn Trommelen. But it’s probably a good idea not to take antioxidant supplements, especially around exercise.

Keep in mind that the scientific evidence for this, apart from the Norwegian study, is still limited.


Antioxidants are healthy nutrients in their own right, but a high-dose antioxidant supplement can reduce the adaptive response to exercise. That means inhibition of muscle growth. That is why as a bodybuilder you better leave these supplements, especially around training.

A healthy, varied diet automatically provides sufficient antioxidants without compromising your training performance.


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