What is Penis size anxiety?

Most men have at one point or another wondered how their penis measures up, and research suggests this has left about 55% feeling dissatisfied, although only 12% (about 1 in every 8) consider their member to be small (Lever, Frederick, & Peplau 2006).

Informally known as Penile dysmorphia disorder (PDD) or Small Penis Syndrome, officially, concerns that your penis is too small are classified as a form of body dysmorphia by the primary arbiter of psychological diagnosis the DSM-5 (Villines & Luo 2019).  All of which tells us that penis size anxiety is a common phenomenon, but perhaps a not well understood one.

As a therapist I have encountered patients with concerns about the size of their penis many times, usually as part of my work with erectile dysfunction but occasionally as the presenting problem. As with most issues, knowledge of the problem can be helpful both in treating it and for those looking to overcome it.

Note – as most of the research I have used assumes heterosexual relations and gender conformity this blog is written with those assumption unless otherwise stated.

Why is penis size an issue? – what men say  

When men were asked this question, they identified three causes, (Sharp & Oates 2019).

• Pornography – Porn isn’t known for its subtly when it comes to the human form and as most people know this extends to the male member. In fact for various reason, some practical, some aesthetic, pornography vastly favors abnormally large penis (Spitznael 2015). It appears that knowing that the performers are unusual doesn’t prevent this leaving an impression.
• Comparison with peers – the only other source of information which most men appear to have is a swift comparison in the changing room. This is unlikely to be reassuring, after all they are checking because they are insecure about it which will skew perceptions.
• Indirect appearance related teasing – The small penis is a staple of comedy, both in popular media and during bawdy talk. The current use of the phrase “big dick energy” to describe a confident man is just one example. These ambient social signals of big equating to good and small equating to bad are absorbed by any concerned male. What is interesting to note is that there is little evidence that direct mocking of the penis is common, either by men or women.

However, what men say about sources which heighten penis size anxiety tells us little about why it is an issue at all?

Why is penis size an issue? – Evolutionary theory  

First thing to note; Human penis’s are massive! … at least compared to our nearest relatives, the other primates, you literally have a bigger dick than a gorilla (Maslin 2017). This suggests a deep evolutionary reason for cock size. One theory is that at some point in our evolution penis size was used as a sign to potential partners of our general health and well-being (Mautz, Wong, Peters,& Jennions 2013).  There is some evidence that women do find slightly larger penis’s more attractive, although the emphasis is on ‘slightly’, as the extra attractiveness benefit tops out quite quickly (Mautz, Wong, Peters,& Jennions 2013).

It can be seen that penis size, along with erectile function, is likely to have been an evolutionary adaptation used to demonstrate health and wellbeing to potential mates (Cellerino & Jannini, 2005),*¹ So is it any wonder that it is a source of anxiety for so many men. Considering this, the existence of anxiety around penis size makes sense. However, in a world where clothing conceals the penis and the only serious chance most  get to measure up is the distorted world of pornography, what men really need is good quality data.

Penis Size – how big is an average cock

A recently published landmark systematic review and meta-analysis of studies of 33 studies from around the world which included some 36,883 participants found that average global penile length is  is 5 inches or 12.8 cm (see table 1) when erect and 3.6 inches or 9.2 cm when relaxed, with a circumference (girth) of 4.7 inches (Mostafaei, Mori, Katayama, Quhal, Pradere, Yanagisawa, Laukhtina, et al 2025).

Table 1. World average penis size (human)

Penis size – growers and showers

Commonly men are categorized into either being ‘growers’, men whose penis is small when at rest, but may grow substantially when erect and men who are ‘showers’, relatively big when relaxed but does not necessarily grow that much. Some men who are ‘growers’ are self-conscious of how small their penis is when at rest, however, what evidence we have indicates that being a ‘grower’ is quite normal, with more than a quarter of men fitting this category. Further, on average ‘growers’ appeared to have larger penis’s when erect (Yafi, Alzweri, McCaslin, Libby, Sangkum, Sikka & Hellstrom 2018).

Hopefully you can now measure yourself up against the world average from base to tip and conclude that you are fairly close to normal, but does it really matter? For many men, its what their partner or potential partner thinks that really matters.

Penis size – what do women want?

For men the issue of penis size can largely be summarized as assuming that bigger is better, but is this what women think?

As was noted above, women do appear to find slightly larger cocks attractive, but the emphasis really is on the ‘slightly’ and very quickly bigger stops being better (Mautz, Wong, Peters,& Jennions 2013). A study which may throw additional light on this found that women looked for slightly larger penis size in transitory partners, (Prause, Park, Leung, & Miller, 2015) such as one night stands, where the larger appendage may have a novelty value . However, when considering life partners women found a penis closer to the average more attractive (Prause, Park, Leung, & Miller, 2015). All of this may reflect what I’m calling the ‘Right key for the right lock’ phenomena, in which women preference the penis which fits their vaginal capacity (average 5.1 inches [13cm] with 1 inch [3cms] elasticity, meaning there is room for 6.1 inches before it starts to get uncomfortable) (Matthes & Zucca-Matthes 2016).

Further, most women express satisfaction with their partners penis size  (Lever, J., Frederick, D. A., & Peplau, L. A. (2006) and the vast majority consider length unimportant, but are more interested in girth (Francken, Van de Wiel, Van Driel & Schultz, 2002)

Summary

We have seen that penis size anxiety probably has deep evolutionary roots, which are brought forward and embedded by distorting portrayals in pornography, poor information and reinforced by expressed cultural attitudes. Subsequently, we have found out how big the average penis actually is and that the issue appears to be much less important to women than men. In the subsequent blog I will examine how Small Penis anxiety can be treated

Footnotes

*¹ This may also be the root of the male urge to display their erect penis to people perceived as potential sexual partners, its current form being the sending of ‘Cock shots’.

References 

Blake, E (2016) https://www.scientificamerican.com/article/human-monogamy-has-deep-roots/

Cellerino, A., & Jannini, E. A. (2005). Male reproductive physiology as a sexually selected handicap? Erectile dysfunction is correlated with general health and health prognosis and may have evolved as a marker of poor phenotypic quality. Medical Hypotheses, 65(1), 179-184.

Costa, R. M., Miller, G. F., & Brody, S. (2012). Women who prefer longer penises are more likely to have vaginal orgasms (but not clitoral orgasms): Implications for an evolutionary theory of vaginal orgasm. The Journal of Sexual Medicine, 9(12), 3079-3088.

Francken, A. B., Van de Wiel, H. B. M., Van Driel, M. F., & Schultz, W. W. (2002). What importance do women attribute to the size of the penis?. European urology, 42(5), 426-431.

Lever, J., Frederick, D. A., & Peplau, L. A. (2006). Does size matter? Men’s and women’s views on penis size across the lifespan. Psychology of Men & Masculinity, 7(3), 129.

Maslin (2017)  https://theconversation.com/why-did-humans-evolve-big-penises-but-small-testicles-71652

Matthes, A. C. S., & Zucca-Matthes, G. (2016). Measurement of vaginal flexibility and its involvement in the sexual health of women. J Women’s Health Care, 5(302), 2167-0420.

Mautz, B. S., Wong, B. B., Peters, R. A., & Jennions, M. D. (2013). Penis size interacts with body shape and height to influence male attractiveness. Proceedings of the National Academy of Sciences, 110(17), 6925-6930

Mostafaei H, Mori K, Katayama S, Quhal F, Pradere B, Yanagisawa T, Laukhtina E, König F, Motlagh RS, Rajwa P, Salehi-Pourmehr H, Hajebrahimi S, Shariat SF. A Systematic Review and Meta-Analysis of Penis Length and Circumference According to WHO Regions: Who has the Biggest One? Urol Res Pract. 2025 Mar 7;50(5):291-301. doi: 10.5152/tud.2025.24038. PMID: 40248849; PMCID: PMC11923605.

Prause, N., Park, J., Leung, S., & Miller, G. (2015). Women’s preferences for penis size: a new research method using selection among 3D models. Plos one, 10(9), e0133079.

Sharp, G., & Oates, J. (2019). Sociocultural influences on men’s penis size perceptions and decisions to undergo penile augmentation: a qualitative study. Aesthetic Surgery Journal, 39(11), 1253-1259.

Spitznael (2015) https://www.menshealth.com/trending-news/a19548129/becoming-male-porn-star/

Villines & Luo (2019) https://www.medicalnewstoday.com/articles/324569

Yafi, F. A., Alzweri, L., McCaslin, I. R., Libby, R. P., Sangkum, P., Sikka, S. C., & Hellstrom, W. J. (2018). Grower or shower? Predictors of change in penile length from the flaccid to erect state. International Journal of Impotence Research, 30(6), 287-291.