Supplements are best used in situations where an individual is unable to get their nutrients from their diet. Perhaps an individual has an allergy or intolerance, for example lactose. They are unable to consume milk products which in turn limits their ability to get sufficient calcium and vitamin D from their diet. In that case, a supplement makes sense.
Currently, one study that induced a fracture unto a rat bone and injected 20mg/kg of Velvet Antler polypeptides into the area every other day for 7 weeks noted that fracture healing rate was dose-dependently increased at weeks 4-7 relative to control and that the bone loading weight was increased following rehabilitation with 10mg/kg (60.7%) and 20mg/kg (93% more than control) after 7 weeks. An in vitro study suggested that this was due to a concentration-dependent mitogenic activity on osteoblastic precursors and chondrocytes.
Deer antler velvet can act as a natural adaptogen, restoring homeostasis to an unbalanced body by helping where it is needed. Deer antler velvet has an effect on many systems of the body given its complex chemical composition. The active ingredients in deer antler velvet are mostly precursors that are required by the body to process substances that maintain its health and wellbeing.
From cave people to you and me. Deer antler is easily consumed as a nutritional source for over 2000 years of recorded history, and no doubt long prior to the written word. Old school energy for modern stress. Used as a trophy from hunters, deer antler has been used as a superfood high in unique protein that will strengthen tissues and increase resistance to physical stress. Later, you'll see more about how that has become science today.
Velvet antler in the form of deer antler spray has been at the center of multiple controversies with professional sports leagues and famous athletes allegedly using it for injury recovery and performance enhancement purposes. In mid-2011 a National Football League (NFL) player successfully sued a deer antler velvet spray manufacturer for testing positive for methyltestosterone in 2009 for a total amount of 5.4 million US dollars. In August 2011, Major League Baseball (MLB) added deer antler spray to their list of prohibited items because it contains "potentially contaminated nutritional supplements." 
“Nutronics Labs Deer Antler Spray is an incredible product. After just a few days of using it, I noticed a significant decrease in the chronic knee arthritis pain I’ve suffered from for many, many years due to dancing and sports injuries. As an added bonus, my ENTIRE body suddenly felt lighter, and generally pain free…it wasn’t until taking the product that I realized most of my joints had been stiff and achey. I had been living in pain for years without even realizing it, having become accustomed to being constantly uncomfortable and sore. I was able to work out harder, recover faster, and noticed significantly increased flexibility and overall mobility. I noticed substantial improvement in muscle tone.
Research in Korea, New Zealand and China has shown that deer antler velvet can stimulate the immune system. Extracts of deer antler velvet were variously shown to increase macrophage activity, stimulate the production of lymphocytes and increase the number of red and white blood cells. Each of these effects may directly complement the body’s ability to resist or fight disease and so promote and maintain health and an associated feeling of well being.