There are a number of ways that you can increase the muscle mass and hair that involves both lifestyle modification and medication.
Both the factors depend on lot of factors and not just testosterone levels. The most important factor is the number of testosterone receptors. Even if the testosterone levels are normal, if the number of receptors is less, it mimics testosterone deficient condition. Another factor that determines the function of testosterone is an enzyme that converts it into an active form called dihydrotestosterone. There are medications to improve this substrate and hence allow better muscle build and hair distribution.
I would recommend the following-
1) Anabolic steroids can be used for medical improvement of male features. Anabolic steroids are similar in structure to the male sex hormone, testosterone, so they enhance male reproductive and secondary sex characteristics (testicle development, hair growth, thickening of the vocal cords). They have their adverse effect and discuss it with your physician before use.
2) Injectable Beta-2 Adrenergic Agonists like Salbutamol and terbutaline can be used and they have better safety profile. The most important side effect being hypotension.
3) Regular exercise and cardio can compound the effect of these drugs and is advised.
4) Eat a good balanced diet with good portion of proteins carbohydrates and vitamins. Consume diet rich in green leafy vegetables and milk.