Yes, lifting weights can help improve bone density. Weight-bearing exercises, including resistance training like weight lifting, are effective in stimulating bone formation and increasing bone density. Here's how it works:

Mechanical Load: When you lift weights, your muscles pull on your bones, which applies stress to the bone tissue. This stress stimulates the bone-forming cells called osteoblasts to increase bone production.
Improved Muscle Strength: Stronger muscles provide better support and stability for bones, which can reduce the risk of falls and fractures.
Hormonal Response: Weight lifting can increase the production of hormones such as growth hormone and testosterone, which play a role in bone growth and density.
Site-Specific Benefits: Resistance training can target specific areas of the body, leading to increased bone density in those regions. For example, lifting weights with your arms can improve bone density in the wrists and arms.
Prevention of Bone Loss: Regular weight-bearing exercise can help prevent bone loss associated with aging, particularly in postmenopausal women who are at higher risk for osteoporosis.

To maximize bone health benefits, it's recommended to engage in a routine that includes a variety of weight-bearing and resistance exercises, along with maintaining a balanced diet rich in calcium and vitamin D. Consulting with a healthcare provider before starting a new exercise regimen is also advisable, especially for individuals with existing health conditions.