A “grower” is a man whose penis increases significantly in length when going from a flaccid to an erect state. The counterpart is a “shower,” whose penis stays closer to the same size whether soft or hard. In clinical terms, a grower gains at least 4 cm (about 1.6 inches) during erection, while a shower gains less than that. These are colloquial terms, but researchers have studied the distinction seriously enough to put real numbers behind it.
How Growers and Showers Are Defined
A 2018 study published in the International Journal of Impotence Research measured 278 men and used the median length change from flaccid to erect, 4.0 cm, as the dividing line. Men who gained 4 cm or more were classified as growers; those who gained less were showers. Growers in the study gained an average of 5.3 cm (just over 2 inches), while showers gained an average of 3.1 cm (about 1.2 inches).
This means the difference between the two groups isn’t dramatic in absolute terms. It’s roughly an extra inch of growth. But visually and psychologically, the distinction can feel significant: a grower may look noticeably smaller when soft yet end up larger when erect than someone who appeared bigger in the locker room.
How Common Is Each Type
In that same study, about 26% of men qualified as growers and 74% as showers. So most men don’t experience a huge change in size between states. That said, the study used a specific clinical cutoff, and in reality the spectrum is continuous. Plenty of men fall near the middle and wouldn’t clearly identify as one or the other.
Flaccid Size Does Not Predict Erect Size
One of the most consistent findings across penile research is that flaccid length is a poor predictor of erect length. A separate study measuring both states in a large group of men found a mean flaccid length of 8.8 cm and a mean erect length of 12.9 cm, but the correlation between the two was weak. Neither a man’s age nor the size of his flaccid penis accurately predicted how large he would be when erect. This is essentially the grower phenomenon in statistical form: what you see soft tells you very little about what you’ll see hard.
What Makes Someone a Grower
The penis contains spongy erectile tissue reinforced by a network of collagen fibers. When flaccid, those fibers are crimped and folded, keeping the tissue compact. During erection, blood flow expands the tissue, the collagen fibers straighten, and the overall structure stiffens and lengthens. In growers, this expansion is more dramatic, likely because the erectile tissue has greater elasticity when soft, allowing it to compress into a smaller resting state.
The only factor that significantly predicted grower status in multivariate analysis was younger age. Growers in the study averaged 47.5 years old, while showers averaged 55.9 years. This makes physiological sense: connective tissue loses elasticity with age, so the erectile tissue in older men may not contract as tightly when flaccid, keeping the resting length closer to erect length. Race, smoking history, other health conditions, and erectile function showed no meaningful difference between the two groups.
Interestingly, growers in the study had a larger average erect size (15.5 cm, or about 6.1 inches) compared to showers (13.1 cm, or about 5.2 inches), despite the two groups having similar flaccid lengths. So growers aren’t simply men with smaller soft penises. They’re men whose tissue is capable of a wider range of expansion.
Temporary Factors That Affect Flaccid Size
Your flaccid size isn’t fixed throughout the day. Several everyday factors can make any man look more like a grower temporarily:
- Cold temperatures cause the body to pull blood away from extremities to conserve heat, shrinking flaccid size noticeably.
- Stress and anxiety constrict blood vessels, reducing blood flow to the penis.
- Intense exercise triggers adrenaline, which diverts blood to muscles and can make the penis appear significantly smaller.
- Infrequent erections can lead to temporary shrinkage over time, though this reverses with resumed activity.
All of these are reversible and normal. They don’t reflect your actual size category so much as your body’s moment-to-moment priorities for blood flow.
Does It Matter for Sexual Function
The short answer is no. The study found no differences between growers and showers in erectile function or rigidity. Being a grower doesn’t mean better or worse erections, and it has no connection to sexual performance or satisfaction. The distinction is purely about how much the penis changes in size between its two states, not about how well it works in either one.
For many men, understanding the grower-shower spectrum is simply reassuring. If your flaccid size seems small relative to what you see in others, it’s worth knowing that soft size is essentially random when it comes to predicting what happens during arousal. The research is clear on this point: you genuinely cannot judge erect size from a flaccid penis.