Too Much Antioxidants | Effect on Muscle Growth


Table of Contents

“Too much of anything is bad.” This popular adage applies to almost everything in life. And quite frankly, vitamins and antioxidants are no exception. Thanks to mainstream media and certain figures, vitamins and antioxidants supplementation has increased significantly over the past 2 decades. While vitamins and antioxidants play a key role in maintaining optimal health, giving the body more it needs can turn ugly. Yes, the body will flush out excess amounts of vitamins and antioxidants, however, they won’t leave without causing a bit of damage first.


  • Too much of anything is not good, including anti-oxidants.
  • Supplementing with mega doses of anti-oxidants will interfere with athletic performance and muscle gains.
  • Too much anti-oxidants will disrupt exercise mediated adaptations such as insulin sensitization and mitochondrial biogenesis.
  • The ratio of oxidants to anti-oxidants is what truly matters.
  • Mega doses of anti-oxidants can reduce your body’s capability to activate its antioxidant defense mechanisms. Moreover, “unused” antioxidants can turn into pro-oxidants. This will inhibit redox balance and risk cellular damage.


Legitimate Usage – Deficiencies

Before you assume that I am attacking those micronutrients, allow me to say, I am not! They are essential for optimal health and optimal body function. But, when is supplementing with mega doses of those substances justified? The only time anyone should supplement with additional vitamins, minerals, or antioxidants is if they have clinical deficiencies, or their diets are sub-optimal. A well-balanced diet will automatically provide the body with just the right amounts of micronutrients. Additionally, since exercise in general, and strength training precisely increases the demands for macro and micronutrients, trainee’s focus should be on structuring a solid diet plan. Sub-optimal intake of macronutrients and micronutrients will lead to sub-optimal recovery, and thus muscle growth. More importantly, one’s health will suffer as well. In short, if your diet is optimal, chances are you don’t need additional vitamins, minerals, or antioxidants.

More is not better

antioxidants become prooxidants
Photo Credits: ThioZyme AO

The problem with supplementing with extra vitamins and antioxidants is that people take it a bit too far. In a sport where the “more is better” mentality prevails, strength trainees consume mega doses of those micronutrients in hopes of making more progress. Here is why doing so can have the opposite effect.

Oxidation is a chemical reaction that produces free radicals. Ultimately, oxidation results in a chain reaction that can damage cells. Oxidants are naturally produced in the body and can be found in the surrounding environment. On the other hand, antioxidants help protect cells by removing those free radicals (oxidants) from the body. Two antioxidants that have gained popularity over the past few decades are vitamins C and E. This can be majorly attributed to the myriad of studies that have found strong links between free radicals and certain diseases like cancer and heart problems. As usual, mainstream media and supplement companies rode the wave and started advertising the alleged healing powers of antioxidants. Antioxidant products flooded the markets and people went crazy. What you may not know is that the human body also produces its own antioxidants! Our bodies do so to remove free radicals and protect us from viruses and harmful microbes. Thus, common sense would tell us to load up on antioxidants, right? Not exactly. It turns out that there is good in every evil. There are three problems with mega-dosing on antioxidants:

  1. Our bodies capability of activating their oxidants defense mechanisms decrease significantly.
  2. Unused antioxidants can turn into pro-oxidants!
  3. Free radicals induced through exercise play a key role in exercise adaptations.

redox balance
Several studies have found that a balance between antioxidants and oxidants is essential for optimal health and function. This is known as “redox balance”. In a state of redox balance, there is an optimal ratio or antioxidants to oxidants. An absence of extra antioxidants guarantees that very little, if any, antioxidants will turn into pro-oxidants. Since it’s impossible to acquire mega doses of antioxidants through our diets alone, we can guarantee an optimal ratio of antioxidants to oxidants by sticking to a sound nutrition plan. Normal dosages of antioxidants help re-establish redox balance at the cellular level. However, consuming mega doses of antioxidants has been shown to disrupt this process by throwing off the balance between oxidants and their counterparts. It’s like shooting yourself in the foot.

Athletes and reactive oxygen species (ROS) (Free Radicals)
Many processes take place in response to exercise. One of those critical processes is the production of reactive oxygen species (ROS) in skeletal muscle. Athletes, especially bodybuilders, used to consume mega doses of anti-oxidants in hopes of preventing the formation of exercise-induced oxidants. This, in their minds, would put their bodies in favorable positions as far as recovery is concerned. What’s odd is that ROS plays a role in exercise and muscle adaptations through mitochondrial biogenesis. After a bout of exercise, the body upregulates its defense mechanisms and mitochondrial activity increases. This ensures that the body can face this threat next time it does (adaptation). In a study conducted on rats (yes, rats), researchers divided rats into four groups:

  1. Sedentary control diet. This group did not perform any exercise and consumed a regular diet.
  2. Sedentary antioxidant diet. This group did not perform any exercise but consumed a diet high in antioxidants (vitamin E and alpha-lipoic-acid).
  3. Exercise control diet. This group exercised and consumed a regular diet.
  4. Exercise antioxidant diet. This group exercised and consumed a diet high in “ao’s” (vitamin E and alpha-lipoic-acid).

ResultsResearchers found that both groups who consumed high amounts of anti-oxidants had less activity of antioxidant defense mechanisms as well as decreased activity of mitochondrial biogenesis. Both groups ability to build muscle mass was suppressed regardless of exercise status.

In another study, researchers found that taking high doses of vitamins C and E interfered with muscular adaptations in young lifters, but had positive effects in older lifters. The exact mechanisms are unknown. Even though this study has its limitations, the results were still consistent with what other similar studies have found.

Another study found that taking vitamin C in doses larger than 1 gram per day significantly reduced exercise-induced adaptation by decreasing mitochondrial biogenesis.

A study by Restow et al. (2009) found that loading up on vitamins C and E inhibited the insulin-sensitizing effects of exercised. Thus, endogenous exercise adaptations are often disrupted when mega doses of “ao’s” are thrown into the mix!

Bottom Line
As usual, too much of a good thing can turn ugly. Antioxidants are no different. Having a healthy balance of anti-oxidants to oxidants is key to optimal health and optimal gains. Supplementing with mega doses of ao’s can inhibit endogenous exercise-induced adaptations, inhibit the body’s antioxidants defense systems, and throw off the redox balance by increasing the number of free radicals (anti-oxidants turning into pro-oxidants) Scientific literature suggests that athletes, and sedentary individuals should rely on their diets to consume just the adequate amounts of antioxidants without overdoing it. Balance is key.

Bohn, J. B. (2010, Jul-Aug). Exogenous antioxidants—Double-edged swords in cellular redox state. Retrieved from Oxidative Medicine and Cellular Longevity:
Braakhuis, A. J. (2012, July). Effect of Vitamin C Supplements on Physical Performance. Retrieved from Current Sports Medicine Reports
Gøran Paulsen, K. T. (2014, July 5). Can supplementation with vitamin C and E alter physiological adaptations to strength training? Retrieved from BMC Sports Science, Medicine, and Rehabilitation:
Hamilton, S. K. (2005, July 25). ANTIOXIDANTS AND EXERCISE. Retrieved from Clinics in Sports Medicine – Volume 18, Issue 3, 1 July 1999, Pages 525–536:
Merry TL, R. M. (2016, Sep 15). Do antioxidant supplements interfere with skeletal muscle adaptation to exercise training? Retrieved from The Journal of Physiology:
Michael Ristow, K. Z. (2009, March 31). Antioxidants prevent health-promoting effects of physical exercise in humans. Retrieved from National Academy of Sciences:
Strobel NA, P. J. (2011, June). Antioxidant supplementation reduces skeletal muscle mitochondrial biogenesis. Retrieved from Medicine and Science in Sports and Exercise:
Bentley DJ, Ackerman J, Clifford T, et al. Acute and Chronic Effects of Antioxidant Supplementation on Exercise Performance. In: Lamprecht M, editor. Antioxidants in Sport Nutrition. Boca Raton (FL): CRC Press/Taylor & Francis; 2015. Chapter 7-9. Available from:



Follow Us

Get The Latest Updates

Subscribe To Our Weekly Newsletter

No spam, notifications only about new products, updates.