An article in the Hindustan Times states "A male star who started the trend of taking his shirt off in films and a younger star who flaunted his rippling muscles in a double role in a recent hit film also rely heavily on steroids............ Model-actor and former Mr India Aryan Vaid says, "I know of 'trainers' of mega stars who don't know a thing about fitness. All they know is which steroids are legal so they can pump them into their clients. Most of the knowledge they have is off the Internet. But, they do good business because they have big names as their clients, some of whom pay these trainers as much as Rs 1 lakh a month for getting them perfect bodies. I've seen actors and models take injections to bulk up even before photo shoots... they don't realise what it's doing to their body.". In the same article, Satya Chaurasia, the fitness trainer whose clients include Aamir Khan and Hrithik Roshan , and he clarified that none of his clients have ever used steroids. "It's a common practice in Bollywood to take anabolic steroids to bulk up fast for photo sessions or shoots. I don't recommend them because I know the consequences."  Actor John Abraham responding to allegations that his face looked "puffy" from steroid use stated that he used "No steroids" and used protein and multivitamins.  Model Upen Patel also refutes ever taking steroids, and states that he was always athletic.  Most recently there have been allegations about Aamir Khan and his gain in muscle for the film Dangal . 
A vitamin is an organic compound needed in small quantities that cannot be made in cells. In human nutrition , most vitamins function as coenzymes after modification; for example, all water-soluble vitamins are phosphorylated or are coupled to nucleotides when they are used in cells.  Nicotinamide adenine dinucleotide (NAD + ), a derivative of vitamin B 3 ( niacin ), is an important coenzyme that acts as a hydrogen acceptor. Hundreds of separate types of dehydrogenases remove electrons from their substrates and reduce NAD + into NADH. This reduced form of the coenzyme is then a substrate for any of the reductases in the cell that need to reduce their substrates.  Nicotinamide adenine dinucleotide exists in two related forms in the cell, NADH and NADPH. The NAD + /NADH form is more important in catabolic reactions, while NADP + /NADPH is used in anabolic reactions.