The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine . 
Change the location of your ponytail often - wear it high, low, on one side, then the other. Don't wear a ponytail at all if your hair isn't really long enough to need one... otherwise you'll probably be pulling your too-short hair really hard in order to secure it. Click here for tips on safely securing the hair during exercise .
Avoid using clipped in ponytails - the weight of them can - quite literally - tear out your hair.
Always use fabric covered hair bands - avoid bare rubber bands like the plague! And remove bands, clips and ponytail holders from the hair at night - this is when you may be putting your hair under tension without even realizing it.
A key aspect of hair loss with age is the aging of the hair follicle.  Ordinarily, hair follicle renewal is maintained by the stem cells associated with each follicle. Aging of the hair follicle appears to be primed by a sustained cellular response to the DNA damage that accumulates in renewing stem cells during aging.  This damage response involves the proteolysis of type XVII collagen by neutrophil elastase in response to the DNA damage in the hair follicle stem cells. Proteolysis of collagen leads to elimination of the damaged cells and then to terminal hair follicle miniaturization.