Bunions form when the bone at the base of your big toe gradually shifts out of alignment, pushing the tip of the toe toward the smaller toes and creating a bony bump on the side of the foot. About 23% of adults between 18 and 65 develop them, and that number jumps to nearly 36% in people over 65. The causes aren’t a single factor but a combination of genetics, foot mechanics, footwear choices, and the daily demands you put on your feet.
Inherited Foot Structure
The shape of your foot is largely something you’re born with, and certain structural features make bunions far more likely. If you have a parent or sibling with bunions, your risk is significantly higher than the general population. What runs in families isn’t the bunion itself but the foot shape and joint mechanics that set the stage for one: things like the angle of your metatarsal bones, the looseness of your ligaments, and how your arch distributes weight.
Scientists haven’t identified a single gene responsible. Bunions follow a complex inheritance pattern, meaning multiple genetic factors interact with each other and with your environment. Some people inherit a foot type that will develop a bunion regardless of what shoes they wear, while others have a borderline structure where lifestyle choices tip the balance.
How Flat Feet and Overpronation Contribute
Your gait, the way your foot strikes the ground and rolls through each step, plays a direct role. Overpronation happens when your foot rolls too far inward as you walk, and it’s closely linked to flat feet. When your body weight is unevenly distributed across the foot with each stride, the big toe joint absorbs more lateral force than it’s designed to handle. Over months and years, that repeated stress nudges the joint out of position.
Hypermobility in the foot joints makes this worse. If the joint at the base of the big toe has more range of motion than normal, it’s less stable and more susceptible to drifting. People with both flat feet and joint hypermobility are at particularly high risk, because they have both the misaligned force and the structural flexibility for that force to exploit.
The Role of Footwear
Shoes don’t cause bunions from scratch in a perfectly structured foot, but they can accelerate the process dramatically in a foot that’s already predisposed. The two biggest culprits are narrow toe boxes and elevated heels, often found in the same shoe.
A narrow toe box squeezes the toes together, physically forcing the big toe toward the second toe and aggravating the bony bump at its base. High heels compound the problem by shifting your body weight forward onto the ball of the foot, increasing pressure on the forefoot. They also change the way you walk, limiting natural toe movement and placing extra stress on the joints. Over time, this combination doesn’t just cause pain. It speeds up the structural change in the joint itself.
This is one reason women develop bunions more often than men. Years of wearing pointed or narrow shoes create a slow, cumulative effect. But men who wear tight dress shoes or work boots with cramped toe boxes face similar risks.
Why Women Are More Affected
Women develop bunions at significantly higher rates than men, and footwear is only part of the explanation. Hormonal changes during pregnancy and menopause also play a role. During pregnancy, the body releases hormones that loosen ligaments throughout the body, including in the feet. This increased laxity, combined with weight gain, can allow the big toe joint to shift. Menopause brings its own hormonal shifts that can worsen existing bunions.
Women also tend to have slightly more flexible connective tissue than men on average, which may make their foot joints more susceptible to gradual misalignment under repetitive stress.
Occupational and Lifestyle Stress
Jobs that keep you on your feet for hours, particularly in one spot, put sustained pressure on the forefoot. Retail workers, restaurant staff, nurses, and factory workers all face elevated risk. The longer and more frequently you stand, the more cumulative stress your toe joints absorb. When that standing happens in shoes without adequate arch support or with a narrow fit, the effect compounds.
It’s not just standing. Any repetitive activity that loads the forefoot counts. Runners and ballet dancers, for example, place extreme and repeated force on the big toe joint. Over time, this repetitive loading can accelerate misalignment in someone whose foot structure is already vulnerable.
How Bunions Progress
Bunions don’t appear overnight. They develop gradually, often over years or decades, and they don’t reverse on their own. Doctors classify severity by the angle of deviation in the big toe. A mild bunion involves a smaller shift, while a severe bunion means the big toe has angled more than 40 degrees toward the other toes. The worse the angle, the more the bump protrudes and the more likely you are to experience pain, swelling, and difficulty finding comfortable shoes.
Early on, you might notice a slight bump that only hurts after a long day. As the condition progresses, the bump grows more prominent, the skin over it may become red and irritated, and the second toe can start to crowd or overlap. Some people develop calluses where the shifted toes rub against each other or against their shoes.
Managing Bunions Without Surgery
Most bunions can be managed conservatively, especially when caught early. The first and most impactful change is footwear: switching to shoes with a wide toe box and low heel removes the external force that worsens alignment. Custom or over-the-counter orthotics can help redistribute weight across the foot and correct overpronation, addressing one of the root mechanical causes.
Toe spacers and bunion pads can reduce friction and provide some relief from pressure on the bump. Physical therapy focused on strengthening the small muscles of the foot may help stabilize the joint and slow progression. Stretching the calf and Achilles tendon also matters, because tightness in the back of the lower leg increases forefoot pressure.
These approaches manage symptoms and can slow the bunion’s progression, but they won’t straighten the toe back to its original position. When pain interferes with daily activities and conservative measures stop working, surgery to realign the joint becomes an option. Recovery timelines vary depending on severity, but most people are looking at several weeks of limited weight-bearing followed by a gradual return to normal activity.