Does Moustafa Ismail increase his biceps with help of nutrition and trainings?

The Egyptian bodybuilder Moustafa Ismail has the largest biceps in the world. He was recorded in the Guinness book of the world records. This guy says that his large biceps are natural. Moustafa Ismail says that he has the largest arms in the world because he has very strict diets and workouts. The Egyptian bodybuilder eats chickens, almonds and fish every day. He also consumes much water and protein shakes.
Although it is obvious that nutrition and trainings play significant role, numerous individuals doubt about natural arms of Moustafa Ismail. It is hard to believe that appropriate workouts and nutrition can cause such increase in arms. Which factors are responsible for the large arms of the bodybuilder?
When it was reported that Moustafa Ismail’s arms were 32 inches, accusations connected with application of steroids appeared immediately. Certain people suppose that anabolic steroids are responsible for the massive arms of this guy. What did Moustafa Ismail say about application administration of anabolic steroids? He claimed that he had applied anabolic steroids while living in Egypt. Purchase and usage of these medications are legal under laws of this country. These medicines are sold at any drug store in Egypt. Moreover, anabolic steroids are cheap there. But Moustafa Ismail claimed that he had to stop applying these remedies, when he moved to the USA. It is know that purchase and usage of these medications without a prescription are claimed to be illegal under laws of the US. These medicines are bought on the black market by those that apply them in the US illegally. Thus, Moustafa Ismail stopped administering these products after he moved to the USA.
But if even the Egyptian bodybuilder takes steroids, it doesn’t matter because these drugs don’t increase arms. They are not responsible for the bodybuilder’s massive arms.
There are other remedies which can enhance arms. They are named “site enhancement oils” (SEO). Synthol is one of the most often taken SEO. This preparation is applied by bodybuilders. It is administered in order to increase muscles in circumference. Thus, it is supposed that Moustafa Ismail uses Synthol. However, Moustafa Ismail says that he doesn’t take this remedy.
The bodybuilder says that he is hurt by accusations related to anabolic steroids and Synthol. He has been subjected to examination conducted by an independent doctor that hasn’t found  any abnormality in the arms of this guy. So, it is unclear whether his arms are natural or not.