Too Much Moisture

A: The short answer is yes, hair can technically have too much moisture, but it's not quite as straightforward as you might think.
The second type of moisture overload happens with hair products, but this is much less common than people think. What often gets mistaken for "too much moisture" is actually a protein-moisture imbalance. Your hair needs both protein and moisture to stay healthy and strong. If you're using lots of moisturizing products but not enough protein-based treatments, your hair can become overly soft, stretchy, and weak.
Here's how you can tell if your hair might be experiencing moisture overload: it feels mushy or gummy when wet, stretches excessively without bouncing back, feels limp even when clean, or breaks easily during styling. If you notice these signs, you might need to use some protein treatments to restore balance.
For water-related moisture damage, prevention is key. When you're swimming or spending time at the beach frequently, consider using protective products. A light application of hair oil, leave-in conditioner with silicones, or even a styling wax can create a barrier that helps prevent excessive water absorption. These products essentially coat the hair shaft and reduce how much water can penetrate the cuticle.
The amount of time needed to cause significant water damage is considerable. We're talking about hours of exposure, not the few minutes you spend in the shower. However, this damage can be cumulative over time, so if you're a frequent swimmer or live in a very humid climate, taking protective measures is wise.

See also:
Fragile wet hair
Should you not brush hair when wet?
How to recognize damaged hair