Direct conversion from long-acting testosterone replacement therapy to Natesto allows for spermatogenesis resumption: Proof of concept.

All 27 men who converted from long-acting TRT to Natesto had resumption of spermatogenesis within 3 months.

• Twenty-seven men were directly converted from long-acting forms of TRT to Natesto.
• Mean duration on long-acting TRT prior to conversion was 24.3 ± 19 months.
• Mean sperm concentration after converting to Natesto was 50.7 million/ml, considered within the fertile range.
• Semen parameters were assessed 3 months after converting to Natesto.

Ten men had confirmed azoospermia while on long-acting TRT, with the remainder presumed to be azoospermic or severely oligospermic.

• Ten men had semen analyses demonstrating azoospermia while on long-acting TRT.
• The remainder were presumed to be azoospermic or severely oligospermic, which has been well established as an effect of long-acting TRT.
• Despite this baseline, all 27 men showed spermatogenesis resumption after conversion to Natesto.

Testosterone levels were similar between long-acting TRT and Natesto, but estradiol (E2) levels were significantly lower on Natesto.

• Hormones were assessed at baseline, again on long-acting TRT, and 1 month after converting to Natesto.
• Testosterone levels were similar on long-acting forms of TRT and Natesto.
• E2 levels were significantly lower on Natesto compared to long-acting TRT.

One couple achieved a pregnancy 4 months after the patient converted from long-acting TRT to Natesto.

• The pregnancy was achieved 4 months after converting to Natesto.
• This represents a clinical proof-of-concept outcome for fertility restoration via conversion to Natesto.

Natesto, a short-acting intranasal testosterone, maintains spermatogenesis in some men, unlike long-acting TRT which suppresses spermatogenesis.

• Long-acting testosterone replacement therapy (TRT) suppresses spermatogenesis.
• Natesto is described as a short-acting TRT that maintains spermatogenesis in some men.
• This study evaluated whether direct conversion from long-acting TRT to Natesto could allow spermatogenesis resumption without a washout period.