A US man who has staked the uncontested claim of having the smallest penis in the world says he has booked a procedure to enhance his member at least somewhat after soliciting the online public’s financial support for that purpose.

In a brief interview on Saturday, 38-year-old Michael Phillips described himself as “really thankful and surprised” over the GoFundMe platform users who supported his campaign for help to pay for the procedure in question.

“I … never thought anyone would care enough to help,” said Phillips, who has previously explained that the procedure should relieve him of urinary issues resulting from his being only 0.38in (0.97cm) long even when wholly tumescent. “[I am] extremely grateful.”

Phillips shared the news about the procedure after media coverage of his grappling with his medically diagnosed condition – known as micropenis – and his related fundraising campaign prompted a prominent Beverly Hills plastic surgeon to publicly offer to do the job for free.

A spokesperson for Dr Robert Dorman said on Friday that he had not heard whether Phillips would take him up on his offer to perform a procedure involving injection treatment, which the physician made because he was moved by the quality of life problems the potential patient had openly talked about.

Asked about whether he would avail himself of the opportunity for growth extended to him by Dorman, Phillips replied: “I have already booked my procedure with a facility closer to home.”

Phillips, who resides in South Carolina near the state line with North Carolina, said the procedure he is planning to undergo is aimed at increasing his girth to alleviate some – though not all – of the difficulties associated with having micropenis.

His “Help Michael Get Micropenis Enlargement Procedure” campaign launched on GoFundMe on 25 June had raised nearly $13,000 from more than 250 donors as of Saturday afternoon.

Phillips in news media interviews has characterized himself as an advocate for those with micropenis, arguing against the body shaming that can result from the condition.

The condition is exceedingly rare and defined by the Cleveland Clinic as a stretched penile length of less than 2.67in (6.8cm). The clinic says the average such length for adults is 5.25in (3.5cm).

In the course of his advocacy, and almost simultaneously to the outbreak of the war that the US and Israel launched in Iran in late February, Phillips granted TMZ an interview in February in which he challenged anyone on earth to disprove his declaration of having the world’s smallest penis.

Phillips also told the outlet that his micropenis diagnosis all but ruled out penetrative intimacy, severely undermining his dating life. And he recounted how being about the same size as a pinky fingernail when fully aroused meant going to the bathroom was remarkably difficult because his urine “goes everywhere and stuff like that”.

Plenty online have expressed skepticism over the authenticity of Phillips’ story. But he said before going on the British television show This Morning in January to discuss his life that he first had to definitively prove to the production that he was conditioned with a micropenis.

He also acknowledged that he has sent pictures of his reproductive organ to other people before. That included a woman who argued with him online, maintained that she did not want such an image and published a viral social media video in which she called it “by far the smallest one I’d ever seen”.