A bruise forms when small blood vessels near the skin’s surface break open from an impact or injury, leaking blood into the surrounding tissue. That trapped blood pools beneath the skin with no wound to escape through, creating the familiar discoloration you see on the surface. The whole process, from initial hit to full healing, typically takes about two weeks.
What Happens Under the Skin
Your body contains a vast network of tiny blood vessels called capillaries that sit close to the surface of your skin. When you bump into something, fall, or get hit, the force of that impact can crack these delicate vessels open. Think of it like a hairline crack in a water pipe: the blood doesn’t gush out onto the surface, but it seeps into the soft tissue surrounding the broken vessel.
Because there’s no cut or opening in the skin for the blood to exit, it pools in the space between your cells. Your body recognizes this leaked blood as debris that needs cleaning up, and your immune system gets to work breaking it down and reabsorbing it. That cleanup process is what drives the color changes you see over the following days.
Why Bruises Change Color
A fresh bruise typically starts out pinkish or red, reflecting the color of the oxygen-rich blood that just leaked out. Within hours to a day, it shifts to a dark blue or purple as the trapped blood loses oxygen.
From there, your body starts dismantling the hemoglobin, the protein in red blood cells that carries oxygen. An enzyme breaks hemoglobin down into a green-tinted compound, which is why bruises often take on a greenish hue around day four or five. Another enzyme then converts that green compound into a yellow one. So the progression looks roughly like this: red to purple to violet to green to dark yellow to pale yellow, then gone. Most bruises disappear completely within about two weeks, though larger or deeper ones can linger longer.
Why Some People Bruise More Easily
If you feel like you bruise from the slightest bump, several factors could explain it.
Age is one of the biggest. As you get older, the connective tissue supporting your blood vessels gradually weakens. Years of sun exposure accelerate this process. The fat layer beneath your skin also thins with age, removing a cushion that once absorbed impacts before they could reach your capillaries. The result is that even minor contact can rupture vessels that, a decade earlier, would have held up fine. This is why older adults often develop bruises on their forearms and hands with no memory of an injury.
Medications play a major role too. Common over-the-counter pain relievers like aspirin, ibuprofen, and naproxen reduce your blood’s ability to clot, which means a small vessel break bleeds longer and produces a bigger bruise. Prescription blood thinners have an even stronger effect. Corticosteroids thin the skin itself, making the vessels underneath more exposed. Even some dietary supplements, like ginkgo biloba, carry a blood-thinning effect that can increase bruising. Certain antibiotics and antidepressants can also interfere with normal clotting.
The Role of Nutrition
Your body needs specific vitamins to maintain strong blood vessels and effective clotting. Vitamin K is essential for blood clotting. Without enough of it, even small vessel breaks bleed more than they should, and wounds or scabs may take noticeably longer to heal. Most people get adequate vitamin K from leafy greens, but deficiencies can develop in people with digestive conditions that impair fat absorption.
Vitamin C supports the production of collagen, the structural protein that reinforces your blood vessel walls. A shortage weakens those walls, making capillaries more prone to rupturing under pressure. Severe vitamin C deficiency is rare in developed countries, but mild insufficiency is more common and can contribute to easier bruising over time.
How to Minimize a Bruise
Acting quickly after an injury can reduce how large a bruise becomes. Apply an ice pack wrapped in a thin towel to the area for 20 minutes, then remove it. Repeat this several times over the first day or two. The cold constricts the damaged blood vessels, slowing the leak of blood into surrounding tissue and limiting the size of the bruise. Elevating the injured area above heart level, when possible, also helps reduce blood flow to the site.
After the first 48 hours, gentle warmth can help speed recovery by increasing circulation to the area, which helps your body clear the pooled blood faster. Avoid massaging a fresh bruise, as the pressure can damage more capillaries and make things worse.
Bruising That May Signal Something Else
Occasional bruises after a known bump or fall are completely normal. But certain patterns deserve attention. Bruises that appear frequently without any injury you can recall, especially in unusual locations like your torso or back, can indicate a clotting problem. Very large bruises from minor impacts, bruises that take much longer than two weeks to fade, or bruises accompanied by unusual bleeding from your gums or nose may point to an underlying issue with your blood’s ability to clot. Conditions affecting platelet count or clotting factors can present this way, and blood work can typically identify or rule out these problems quickly.