Jiang et al. 2003 — Ejaculation and serum testosterone (later retracted)

What the study found

This paper is the source most often cited for the popular "45% in seven days" testosterone figure. Studying 28 volunteers, it reported that serum testosterone peaked on the seventh day of sexual abstinence, reaching 145.7% of baseline. The PubMed record for the paper (PMID 12659241) now carries a retraction notice. ^[1]

investigated 28 volunteers and reported a testosterone peak on the seventh day of abstinence reaching 145.7% of baseline

^[1]

Why it matters here

This is the single study most often invoked in NoFap and semen-retention discussion to argue that abstinence raises testosterone. Two features limit that use: the result is a short-term peak measured in only 28 men across about a week, not evidence of a durable increase, and the underlying PubMed record now carries a retraction notice. See the check on whether NoFap boosts testosterone for how this evidence is weighed.