Your bones are always rebuilding, breaking down old tissue and replacing it with new cells. Estrogen helps keep that cycle in balance. When estrogen drops during menopause, the breakdown happens faster than the rebuilding, and bones get flimsier. In the first five to seven years after your final period, you can lose 3–5% of your bone density each year. 

Hormone replacement therapy (HRT) for bone loss can slow that natural process and lower your fracture risk. But HRT isn’t the right fit for everyone. Your age, symptoms, and health history are all important factors in deciding if it’s right for you. Here’s how HRT protects your bones, when it works best, and what else to consider.

How does estrogen protect your bones?

Two types of cells drive the bone rebuilding cycle. Osteoclasts (with a C) break down old bone tissue. Osteoblasts (with a B) build new cells to replace it. Estrogen keeps osteoclasts in check: It slows them down so they don’t clear bone faster than osteoblasts can replace it. At the same time, estrogen helps osteoblasts live longer and work more effectively.

When estrogen drops during menopause, that balance tips. Osteoclasts ramp up, and osteoblasts can’t keep pace. Your body starts losing more bone than it rebuilds. Over time, this leads to osteoporosis—a condition where bones become weak enough to break from a minor fall or everyday movement. The bone loss is greatest in the spongy inner bone of your spine, hips, and wrists, areas most likely to fracture later on.

What does research say about HRT and fracture risk?

HRT replaces the estrogen and sometimes progesterone your body stops making. This can restore the balance between bone tissue breakdown and rebuilding. 

The Women’s Health Initiative (WHI) tracked more than 16,000 postmenopausal women to measure whether hormone therapy could prevent fractures. Findings showed that estrogen-plus-progestin therapy lowered total fracture risk by 24%. The trial group on estrogen-only therapy saw even better results: a 29% drop in all total fractures.

Researchers stopped the trial after five years based on a suggestion from the Data and Safety Monitoring Board. This could be because the study found that long-term HRT use increased the risk of breast cancer and stroke. But the risk is relatively low—the FDA has removed cardiovascular disease and breast cancer from HRT’s black box warning. Women who start treatment 10 years before the onset of menopause and before age 60 can safely use HRT indefinitely. 

When is HRT the right choice for bone health?

HRT works best when you start before age 60 or within 10 years of reaching menopause. Starting earlier, especially in the first few years, offers the greatest bone protection. HRT may be a strong option in these situations:

• Early or premature menopause and premature ovarian insufficiency (POI): A longer stretch without estrogen means more years of bone loss. The Menopause Society recommends hormone therapy for these women to protect bone density until the average age of menopause.
• Osteopenia: If your bone density is below normal but hasn’t crossed the osteoporosis threshold, HRT can help prevent further loss. At this time, the FDA hasn’t approved hormone therapy for osteoporosis.
• Intolerance to osteoporosis medications: Some women can’t take osteoporosis medicine because of digestive side effects or preexisting conditions. HRT offers another route to bone protection.

What happens to bone health when you stop HRT?

Bone loss picks back up when you stop HRT. The Menopause Society notes that the pace of loss after stopping is rapid, similar to the rate right after menopause. Within five years, your fracture risk can return to where it would have been without treatment. Studies haven’t found a spike in fractures beyond that baseline, but the protection HRT provides does fade.

Planning ahead can make all the difference. A provider can review your bone density and help you build a transition plan before you stop. That may include switching to a medication designed for osteoporosis, like a bisphosphonate, to maintain the bone you’ve protected.

Building stronger bones with Maven Clinic

Bone health deserves a place in every menopause conversation, not just after a fracture. If you’re already noticing signs of perimenopause in your 40s or a bone density scan has raised alarms, it’s a good time to consider treatment.

Explore Maven Clinic’s Hormone Care program to see if HRT fits into your bone health plan.

FAQ

Should a 70-year-old woman take estrogen?

There’s no automatic age cutoff for HRT. At older ages, providers often recommend the lowest dose of estrogen for osteoporosis prevention and managing other symptoms.

Starting the treatment at 70, though, is a different conversation than continuing it at 70. The further you are from menopause, the more carefully the risks need to be weighed. Most doctors don’t recommend starting HRT after 60.

What’s the #1 vitamin to rebuild bone density?

No vitamin rebuilds bone, but two nutrients are essential for bone health: calcium and vitamin D. Calcium is the main mineral in bones, and the recommended intake for women over 50 is 1,200 mg per day, ideally from food first. Vitamin D helps your body absorb that calcium. The recommended amount is 600 IU per day for women 51–70 and 800 IU for women over 70. Individualized doses are based on lab data.

Can hormone therapy help osteopenia?

Yes. The Women’s Health Initiative (WHI) trial found that HRT reduced fractures regardless of baseline bone density. The role of estrogen in osteoporosis and osteopenia is preventive: It slows bone loss before it progresses. If you’re struggling with osteopenia, combining hormone therapy and bone density monitoring can help you stay ahead of further loss.

Can I use estrogen therapy to treat osteoporosis? 

Currently, the FDA hasn’t approved estrogen therapy for osteoporosis treatment. But HRT can slow bone loss, so talk to your doctor to see whether it’s right for you.