3/31/24 Someone from Dr Pen reached out to me to offer a guidance on how to use this pen. They were very interested in me being happy with my purchase. They walked me through the issues and we followed up with each other for a few weeks. I’m happy to report that the instructions I was given were able to improve my issues. It clarified that the gurgleling sound is normal. It was recommended that I tilt my head to allow for the flow of serum. Having said that I am still having a bit of an issue with it when I am upright. There is not a constant issue but there are times when the serum just flows out rapidly and drips and then there are other times when it does not. I can’t fully blame the pen. It could be the consistency of the serum or that I have not found the right combination of speed and flow. In conclusion, I can say that I am happy with this product and better yet, report that their customer service is outstanding. If you have any doubt based on other reviews, know that their customer service stands by their product and wants to be of help. PRIOR REVIEW: The concept of being able to introduce your own cocktail treatment while microneedling is great! However this pen doesn’t work. Perhaps I received a defective one…who knows. What happened the first time is that the pen would make a gurgling sound, product would either not come out or suddenly come out in a large amount. Second time nothing came out, so I took the vial out checked it placed everything back in and made sure of all my dials were correct. Started again and this time…again all the liquid started coming out at once, gurgling sound again. I stopped the process and quit my session. I might purchase again once all the issues are resolved.