Is 1.0mm depth for PRP hair thinning/loss effective enough?

If your nurse is currently using a 1.0 mm depth setting for PRP scalp treatments, your concern is entirely valid. PRP needs to reach the dermal layer of the scalp, where the hair follicles are located, to stimulate hair growth effectively. Most medical literature and expert consensus recommend injection depths between 2 mm and 5 mm, depending on the region of the scalp and individual anatomy.
Studies have shown that effective PRP delivery for hair restoration typically involves injections at around 2–3 mm, and sometimes deeper, particularly when using mechanical injectors. For example, one clinical study found that PRP injections delivered at 5 mm depth showed significant improvement in androgenetic alopecia, while another review confirmed that 1.5–2.5 mm is an effective range when using manual syringes. These depths allow the PRP to reach the vascular plexus surrounding the follicles — a key area for promoting regrowth.
At 1.0 mm, PRP is most likely staying in the upper dermis or even the epidermis, which may be suitable for microneedling procedures but is generally too shallow for follicular stimulation. If your nurse is performing microneedling with PRP rather than injections, the shallow depth might make sense — but if the treatment is being marketed as PRP injection therapy for hair loss, this depth may not be effective.
You might consider having a transparent discussion with your provider about your concerns and ask why 1.0 mm is being used. It may be an overly cautious setting, or there may be confusion between microneedling and injection techniques. In any case, you deserve to have the procedure performed in a way that aligns with evidence-based practices.
Lastly, this guidance is based on medical research and clinical norms, but it should not replace personal medical advice. Every scalp is slightly different in thickness and sensitivity, so a trained provider should assess your case individually. If you’re not confident in the depth or method being used, it’s entirely reasonable to seek a second opinion — ideally from a board-certified dermatologist or hair restoration specialist experienced in PRP therapy.

The effectiveness of PRP (Platelet-Rich Plasma) therapy for hair thinning or loss can depend on several factors, including the depth of injection. Generally, the scalp's dermal layer, where hair follicles reside, is typically reached at a depth of about 4-6mm. This is why many practitioners aim for this depth to ensure that the PRP reaches the hair follicles effectively.

Using a 1.0mm depth may not be sufficient to deliver the PRP to the follicular level, which could impact the treatment's effectiveness. However, some practitioners might use shallower depths for specific reasons, such as targeting the superficial layers for skin benefits or in cases where the scalp is very thin.

Here are a few steps you might consider:

Consult with Your Practitioner: Discuss your concerns with your nurse or the administering physician. They can explain the rationale behind using a 1.0mm depth and possibly adjust the treatment based on your feedback and treatment goals.

Seek a Second Opinion: If you're unsure about the current treatment protocol, consulting with another experienced professional in PRP for hair loss can provide additional insights and recommendations.

Consider Other Factors: PRP's effectiveness can also depend on the concentration of platelets, the frequency of treatments, and the overall health of your scalp and follicles.

Ultimately, it's important to ensure that your treatment plan is tailored to your specific needs and is based on the latest evidence-based practices.

PRP is not very effective for hair loss. I would suggest Dermapen treatment with 2.0 mm deep with exosome application to reduce the hair loss. However you might need sedation for this.