Vitamin A is indispensable in growth and development: without vitamin A, the level of sex hormones decreases, and in the case of children, sexual maturation and growth slow down.(1, 2) Animal studies prove that the body does not produce a sufficient amount of testosterone if vitamin A levels are deficient. Therefore, vitamin A is important for all who would like to gain muscle.(3) Testosterone’s effectiveness in facilitating muscle growth is illustrated by the fact that testosterone supplements alone, can produce more muscle mass than weight training.(4)

Vitamin A’s role in testosterone production  

Animal studies further prove that vitamin A deficiency decreases the size of testicles, and testosterone production. On the other hand, a higher concentration of vitamin A increased both testosterone production and growth.(3) The most compelling study, however, was conducted with the participation of teenage boys whose sexual development did not begin in due time. In their case, vitamin A and iron supplements had similar effects as a synthetic testosterone derivative.(2)

The study of vitamin A and testosterone supplementation 

102 teenage boys whose sexual development had not yet started participated in the study. They were divided into 4 groups: group one was given 6000 IUs of vitamin A weekly and 12 mg iron supplements daily, group two was given a synthetic testosterone derivative, group three was given all three supplements, and group four, the control group, received neither. 

The vitamin A supplement produced similar results in growth and sexual maturation as the synthetic testosterone derivative. Within one year, both started sexual maturation and increased growth, while the control group experienced no changes during this period. 

The test proves that vitamin A and iron deficiency were likely responsible for the delay in sexual maturation for these boys since the supplements kick started their own hormone production. If the lack of a micronutrient is to blame for a problem, then supplementing that micronutrient is obviously a better solution than taking medicine with synthetic hormones as they might have more side effects. 

Eating liver once a week can provide this amount of vitamin A and iron. Unfortunately, few are aware of the effects and sources of vitamin A. If the participating boys’ parents had heard about it they could have easily prevented the problem. Supplementing vitamin A is, of course, possible through other sources and it’s not only necessary for teenagers but for all ages from infants to the elderly.

The forgotten role of vitamin A for muscle gain 

Modern bodybuilding diets do not contain enough vitamin A, as they usually consist of chicken, egg whites and cereals. Many choose to eat the egg whites only instead of the whole egg, and prefer lean meat and low fat cheeses. This increased protein intake can easily lead to vitamin A deficiency. 

This wasn’t always the case; Vince Gironda, a popular bodybuilder in his own time and a pioneer in nutrition in the 1950s recommended a diet consisting of whole eggs, liver, beef and full fat dairy products in large amounts. Based on his own and his clients’ experience he realized that vital nutrients can be found in these foods. He recognized the key role of micronutrients in both muscle gain and regeneration after intense exercise. He supplemented his diet with dried liver capsules, marine alga capsules and mineral capsules. 

He was convinced that liver and egg yolk (both rich in vitamin A and other micronutrients) were the most vital parts of a bodybuilder’s diet. His remarkable physique which would be the envy of many even today, was attained through natural means, without using any testosterone derivatives.