Is it necessary to go through PRP after hair transplant?

Thank you for your question. You submitted a question without a photo, described in detail you’re 27-years-old, you underwent hair transplant 3 months ago, and underwent a PRP injection 20 days after your transplant. You’re asking if PRP is necessary to be continued. 
I can help you understand how I discuss this type of situation and comparable situations in my practice. A little background:I’m a Board-certified cosmetic surgeon and Fellowship-trained oculofacial plastic and reconstructive surgeon. I have been in practice in Manhattan and Long Island for over 20 years. I’m also the founder of TrichoStem™ Hair Regeneration Centers based on a technology we developed which partly uses PRP as a non-surgical alternative to hair transplant, and as a solution for men and women with genetic pattern hair loss. This type of question about PRP arises constantly in our practice. I’ll explain a little my thought process for someone like yourself. 
You’re 27 and already underwent a hair transplant, which in my mind means you have an early onset and a relatively aggressive pattern of hair loss. I suspect you’ve had a frontal hairline loss and recession, with significant overall loss. 
You have to understand that transplantation does have a limit, and it’s one of the reasons why, in my training and in the general rule in our specialty, is to minimally operate, if at all, on people who are in their 20s. The reason is because the age of onset and the rate of progression will often outpace the ability of hair transplant to keep up with the degree of loss. When you first noticed hair loss, you’ve already lost about 50% of your hair. By the time you moved forward with the hair transplant, I suspect a much higher percentage of your hair was lost. 
So where does PRP fit in this treatment plan? PRP has two important roles when it comes to hair and transplant. With hair transplant, like in other surgical procedures, there is an improvement in wound healing with since it is a concentration of the wound healing growth factors, and other elements of your blood which, when concentrated, will stimulate blood supply, improve the migration of the epidermis or epithelial cells - it does a lot of things. If you could imagine, if you cut yourself and how it heals, what we’re doing is we’re manipulating that physiologic process by placing PRP strategically. 
In our practice, we use PRP a lot for: acne scars, fine lines and wrinkles, and under eye dark circles. When it comes to hair transplant, we generally do a combination of PRP and something called extracellular matrix. This material is, I feel, the next level of stem cell-based wound healing technology. It’s not stem cells being placed, but a material that stimulates your body’s own stem cell response. When we were doing a lot of transplants, we would combine PRP and Acellular matrix during the transplant to expedite the healing of the grafts, and improve the healing of the donor area. The side-effect and benefit of that process appeared to also stimulate the growth of thinning hairs, and that’s where Hair Regeneration evolved from. 
Hair Regeneration takes PRP and Acellular matrix using a system we developed in our practice where we do these injections to help people who have thinning hair to avoid surgery for the most part by stimulating the growth of their hair, reactivating hair that’s not growing, prolonging the growth cycles, and inducing the shed of thinning hairs to get growth of thicker hairs. With either 1 or at most 2 injections, the overall majority of our patients have sustainable growth for about 5 years. We have over 7 years of experience at this point in time. So that brings me to helping you understand your question about sustaining of PRP.
The question I think your doctor probably also has proposed to you is how to at least slow down your hair loss progression. We can distinguish and differentiate what is available to you. One is the drug finasteride which works by lowering the levels of DHT or dihydrotestosterone, which can have an effect on the progression of thinning. The drug is taken daily in 1 milligram dosage to lower your DHT level. It may or may not work for you because there is a certain rate of progression that is often genetically very strong. It’s been my observation that a DHT blocker can be effective in slowing the progression.
Now where does PRP or where does Hair Regeneration fit in? With this mechanism, we’re stimulating hair growth. Now the differentiation between Hair Regeneration, and PRP is that PRP cannot sustainably maintain hair growth, in my experience, for more than 3 months. In general, my colleagues who are doing exclusively PRP for hair loss will have a patient come in at least once every 3 months, or even earlier. I see it as a short-term burst of growth, which requires continuous treatment. A lot of people who come to us who had PRP injections done elsewhere felt they couldn’t keep going every month, with no endpoint in sight. Can it really sustain that? In many ways, it’s almost a setup for failure because a person can only willingly get injected in the scalp so many times in a given year before they start to fatigue - that is a big differentiation to be understood. 
Hair Regeneration has been so successful, and we treat people from all over the world so we have patients who cannot, in any practical way, come back to us that frequently. We’ve been able to prove this over the many years of doing this combination and algorithm that we developed works in that respect.
How does this fit in the treatment plan for you? In a situation like yours, I would suggest you strongly consider taking finasteride to slow things down, and I would recommend a treatment like Hair Regeneration. If something like Hair Regeneration is not available to you, then at least consider the PRP injections to try to push the growth of your existing hair, possibly to help your grafts as well, but understand you’re trying to delay as long as possible the need for a second transplant. Unfortunately, a lot of young people who have gone this route of transplantation will keep doing it, and by the time they hit their mid to late 30s, they’ve lost their native hair, and only have their transplanted hair which doesn’t look very full at all. It actually looks like their hair is thinning, which is not a very satisfactory outcome. It’s very important to have a plan for your stabilization and prolongation by stimulation of the growth of your existing hair. I hope that was helpful, I wish you the best of luck, and thank you for your question.

It is not a must to have PRP Therapy after your hair restoration. However it can help healing times and promote early growth.