Part of this may be due to the difficulty defining "normal" testosterone levels and "normal" behavior. "This connection is important because it shows that testosterone marketing is not just about health, but is embedded in wider cultural and ideological narratives about gender and power, and the manosphere is not simply an ideology, but also an industry." Despite screening for low testosterone being medically unwarranted in most young men, this group is being aggressively targeted online by influencers and wellness companies promoting hormone tests and treatments as essential to being a "real man", a study published in the journal Social Science and Medicine has found. The study highlights the medicalisation of masculinity, where normal variation in men’s bodies and experiences is reduced to a testosterone deficiency with a simple fix. Then, they performed the feminine or masculine version of the monologue for an audience of two experimenters, one of whom was blind to the gendered version of the performance. For the feminine condition, participants were instructed that their gestures, movements, and behaviors should involve upending sentences, higher voice register, taking up little space, frequent smiles, hesitancy, and infrequent eye contact. Immediately after the video, participants completed a second PANAS and the gender self-ratings and waited 15 min before providing the postmanipulation saliva sample, because effects of social stimuli on hormones occur at a delay (6). He said a single testosterone test, assuming it was accurate, could "at best, only tell you the concentration of testosterone in your blood at the time you took the test". Symptoms commonly attributed to low testosterone were often non-specific and overlapped with fatigue, stress, anxiety, depression and relationship difficulties, Cheung said. Testosterone naturally declines with age but it is not inevitable for all men, and lower levels may also be linked to factors including type 2 diabetes, obesity, metabolic syndrome and the use of certain medications. "This creates a sense of urgency for solutions, which in turn fuels lucrative markets for pharmaceuticals, supplements and medical devices, even in the absence of clear clinical benefit. This meant "men may come to perceive themselves as inherently deficient or in need of medical intervention", she said. They shape how men understand their bodies, ageing and identity, and often lead to negative self-perception and mental health," she said. Although evidence is mixed, some forms of competition do increase testosterone in men, although these are mainly formalized ones with clear win/loss outcomes as with athletic engagements (7, 18). Our research design was able to disentangle wielding power from masculinity using trained actors, providing an innovative new paradigm. We recruited trained actors to act out firing a subordinate, a context that demonstrates one’s own status and power and involves more regular social interactions and dynamics than more formalized competitions such as athletic events. Testosterone has similar evolved functions in women’s and men’s bodies (27), but we have repeatedly found it easier to decrease testosterone in men and increase testosterone in women (3). There may be more than one pathway from gender to testosterone because gender is multifaceted and includes behavior, stereotypes, roles, identity, and so on. In addition, conceptualizations of masculinity tend to overlap with those of power and testosterone (3, 26). Also, mixed evidence suggests that "power poses" can increase testosterone (22, cf. ref. 23). Our findings show that discrete events of gender-related socialization may account for some portion of the observed "sex" difference in adult testosterone levels. A major implication of our experiment is that gender socialization can contribute to variation in human testosterone levels. We found that wielding power increased testosterone for women but not for men, consistent with some of our other studies where experimental manipulations were more successful at increasing testosterone in women (29, 36, 37). We tested these by conducting a repeated measures multivariate analysis of variance that assessed effects of condition (masculine performance, feminine performance, and control condition) on testosterone changes (via percent change scores, which are more sensitive to deviations in testosterone; ref. 6). Competition is crucial to evolution and may increase testosterone but also is selectively discouraged for women and encouraged for men via gender norms. Gender socialization may affect testosterone by encouraging men but not women toward behaviors that increase testosterone. Low testosterone is framed as a health crisis and the hormone is linked to unrealistically muscular bodies and sexual performance. Research suggests that about 20% to 40% of your calories should come from fat for healthy testosterone levels. Another factor to think about when it comes to your environment and healthy testosterone levels is to make sure you’re not bathing in T-killing chemicals. Testosterone is a major influence on bodily and behavioral features seen as male and/or masculine. However, our experiment demonstrates that gender-related social factors also matter, even for biological measures. But the way it’s being promoted to healthy men is highly misleading. Overwhelmingly now, when it comes to health and wellness, people are there to sell you things, and they’ll say, do and look however they need to." Influencers are now an established part of medical marketing and Nickel urges consumers to be sceptical.