How much scalp coverage from a single PRP injection?

Thank you for your question!This needs an in-person evaluation. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. At my practice, I encourage my patients to use our Hair Growth Package that includes AnteAGE MD's Hair Microneedling Kit as well as Restorsea's Revitalizing Hair Treatment.  This package contains topicals and supplements that will help stimulate hair growth and reverse breakage and can be found, along with free consults with a Skin Care Specialist at Emeragecosmetics.com.See an expert. Best, Dr. Emer

The first aspect of your question to point out is that a "single injection" is not a precise measurement how much PRP is injected in one site, as many injectors acquire different techniques of the quantity per injection. The naked eye cannot observe the depth nor width of the spread of their injections. The important thing to know is that PRP "spreads" to wherever it needs to be allocated for enhancing the scalp's cellular mechanisms. Ultimately, PRP will end up primarily around miniaturized hairs that have depleted cellular machinery for growth. Best injection strategies for PRP should involve injecting near sites of miniaturized hairs, which can be visualized by Trichoscopy magnification. Best,Dr. Anil Shah

This  is an excellent question. The answer depends upon how the PRP  is delivered. Ifthe PRP is applied after micro-needling of the skin, there is minimal spread. If an injection is intradermal, meaning is into the skin itself, there is not much spread of the PRP. If an injection is in the subdermal area, there exists an  anatomical space where the PRP can spread. This is the basis behind my subdermal Depo injection technique. Theoretically, gravity can take the PRP inches away from the injection site. Find a PRP expert. Ask to see photos.Jeff Rapaport MDRealself All-star

Hi, How are you? Typically if the PRP treatment is performed correctly, the DR will inject the whole scalp. However, it will not be coverage from new hairs that you will notice. It will be the small, miniaturized hair that you will see begin to get thicker and stronger. Giving you back volume and fullness. If you are looking for a certain amount of coverage you are going to need a hair transplant. PRP is just a prevention. 

There are many factors that can impact how far PRP may migrate and still remain effective. In an ideal world, when prepared and delivered correctly as I use in my protocol, the effective migration range of PRP is not far. My observation have generally been between 0.5cm and 0.75cm. 
If combined with other materials such as exosomes, most of the exosomes will remain in the injection site area. However, the size of exosomes does permit them to migrate significantly further. Other material such as Acell will remain very lose to the injection site due to the particulate size of the material.
Hope I have helped.
Warmly,
Arbella Sarkis, MD

PRP is a great way to grow hair and the number of injections and diffusion varies with the amount that is used.  I often combine PRP with other modalities such as Propecia or Minoxidil or the Laser Cap for the best hair grow results.  Best, Dr. Green