Bone Loss Starts in Perimenopause, Not After Menopause: What to Do Now

Most women think of osteoporosis as something to worry about in their 60s or 70s, after menopause, when a doctor finally orders a bone scan.

The research says otherwise. The fastest bone loss of a woman's life starts while she's still having periods, often before she has any idea she's in perimenopause. By the time she can say for certain she's reached menopause, she may already have been losing bone quickly for two years.

The good news is that this is also the best window to do something about it.

When bone loss really starts

The clearest answer comes from SWAN, which tracked bone density in a multi-ethnic group of midlife women for years and lined up the results against each woman's final menstrual period.

• Bone density loss starts about 1 year before your final period. Bone turnover markers rise even earlier, about 2 years before.
• The fastest loss runs from 1 year before to 2 years after the final period. Researchers call this window the transmenopause.
• During that window, women lose about 2.5% of spine bone density and 1.8% of hip bone density per year.
• After that, loss slows to about 1.1% a year at both sites, but it doesn't stop.

Over the 10 years around menopause, women lost about 10.6% of their spine bone density. About 7.4% of that, roughly 70%, was lost in just those three transmenopause years.

Bone quality suffers too, not just density. SWAN found that trabecular bone score, a measure of the bone's inner structure, starts declining about 1.5 years before the final period.

Why speed matters

It's not only where you start, but how fast you lose. In SWAN, each 1% per year faster decline in spine bone density was tied to a 56% higher risk of later fracture, regardless of starting bone density.

That's why perimenopause matters so much. A woman with good bone density at 45 can still lose a lot in a short time.

Why hormones drive bone loss

Bone isn't static. Your body constantly breaks down old bone and builds new bone. Estrogen and progesterone each help keep that process in balance.

• Estrogen slows breakdown. It restrains the cells that dissolve bone. When estrogen falls, those cells become more active. Estrogen loss also allows immune cells to release inflammatory signals that speed up bone breakdown.
• Progesterone supports building. It helps stimulate the cells that form new bone. As ovulation becomes irregular in your 40s, progesterone often falls first, which may tip the balance even before estrogen drops. More on that in What Does Progesterone Do?

In SWAN, rising FSH and falling estradiol about 2 years before the final period were followed roughly a year later by rapid bone loss. The hormone shift comes first, then the bone loss.

Muscle matters too. Bone responds to the pull of muscle and the force of impact. As estrogen loss speeds muscle decline, bone loses one of its main signals to stay strong. This is part of what researchers now call the musculoskeletal syndrome of menopause.

Who's at higher risk, and when to test

Risk factors that make early bone loss more likely include:

• A parent who broke a hip
• Low body weight or a small frame
• Smoking, or more than a couple of alcoholic drinks a day
• Long-term steroid use, or certain other medications
• Conditions that affect absorption, such as celiac disease
• Rheumatoid arthritis, an overactive thyroid, or other inflammatory and hormonal conditions
• Early menopause, or long gaps without periods earlier in life
• Very low calcium or vitamin D intake

Bone scans

In 2025, the U.S. Preventive Services Task Force recommended bone density screening for all women 65 and older. For postmenopausal women under 65, it recommends a two-step approach: check for risk factors, use a fracture risk tool such as FRAX, and screen with a DXA scan if risk is increased.

That leaves a gap. Routine guidelines don't cover women still in perimenopause, when the fastest loss begins. If you have risk factors, it's reasonable to ask about a baseline DXA as you approach menopause, so you know where you're starting from.

Blood work can help find contributing causes too, including vitamin D, calcium, thyroid, parathyroid hormone, and celiac screening when it fits.

What actually protects your bones

Heavy lifting and impact

For years, women with low bone density were told to stick to walking and light weights. The LIFTMOR trial changed that.

Researchers in Australia randomized 101 postmenopausal women with low bone mass to either a gentle home program or two 30-minute supervised sessions a week of heavy lifting (over 85% of their maximum) plus impact training, for 8 months. The program included deadlifts, back squats, overhead presses, and jumping chin-ups with drop landings.

The heavy-lifting group improved bone density at the hip and spine, gained height, and improved posture and physical performance. No one had a fracture or serious injury. A follow-up analysis found no vertebral fractures and improved upper-back rounding.

The key word is supervised. These women were coached to lift with proper form and progressed gradually. But the message is clear: bone responds to heavy loads, and light exercise alone isn't enough.

Hormone therapy

Hormone therapy is FDA-approved to prevent osteoporosis. In the Women's Health Initiative, estrogen plus progestin cut hip and spine fractures by about a third and total fractures by 24%. Hip bone density rose 3.7% over three years, versus almost no change on placebo.

Because the fastest bone loss starts right around the final period, timing matters. Women considering hormone therapy for symptoms should know bone protection is one of its best-documented benefits.

Progesterone may play a role, too. A review by Seifert-Klauss and Prior found that progesterone appears to prevent bone loss in premenopausal and possibly perimenopausal women, though there's no fracture data yet.

Nutrition

• Protein. Protein is part of bone's structure, and the muscle that loads your bones depends on it. Aim for a good source at every meal.
• Calcium, mainly from food. In 2025, the USPSTF recommended against low-dose calcium (1,000 mg or less) and vitamin D (400 IU or less) supplements to prevent fractures in postmenopausal women, and found too little evidence for higher doses. Food sources, such as dairy, sardines, tofu, and leafy greens, are the better starting point.
• Vitamin D. Test it rather than guess, and correct a true deficiency.
• Limit alcohol and don't smoke. Both speed bone loss.

What doesn't help much

Creatine is popular for women right now, and it does support muscle. But recent meta-analyses found no effect on bone density. More on what the evidence supports in Perimenopause Supplements: What Actually Works.

Your perimenopause bone plan

1. Know your risk. Review the risk factors above. If any apply, ask about a baseline DXA scan before your final period, not after.
2. Lift heavy, safely. Work up to challenging weights two or three times a week, ideally with a qualified coach. Add impact, such as jumping or skipping, if your joints allow.
3. Eat for bone. Get enough protein at each meal and calcium mostly from food.
4. Check your labs. Vitamin D, thyroid, and other contributors are easy to test and fix.
5. Talk about hormones early. If you're a candidate for hormone therapy, starting near menopause protects bone during its fastest loss.
6. Cut what hurts. Smoking and heavy drinking both speed bone loss.

Your 40s aren't too early to think about your bones. They're the most important time.

References

1. Greendale GA, Sowers M, Han W, et al. Bone mineral density loss in relation to the final menstrual period in a multiethnic cohort: results from the Study of Women's Health Across the Nation (SWAN). J Bone Miner Res. 2012. View source
2. Faster lumbar spine bone loss in midlife predicts subsequent fracture independent of starting bone mineral density. J Clin Endocrinol Metab. View source
3. Greendale GA, et al. Trabecular bone score declines during the menopause transition: the Study of Women's Health Across the Nation (SWAN). J Clin Endocrinol Metab. 2020. View source
4. Greendale GA, et al. Estradiol and follicle-stimulating hormone as predictors of onset of menopause transition-related bone loss in pre- and perimenopausal women. J Bone Miner Res. 2019;34(12):2246–2253. View source
5. Seifert-Klauss V, Prior JC. Progesterone and bone: actions promoting bone health in women. J Osteoporos. 2010;2010:845180. View source
6. Mouse studies reveal immune mechanism involved in bone loss caused by estrogen deficiency. EurekAlert. View source
7. US Preventive Services Task Force. Screening for osteoporosis to prevent fractures: recommendation statement. JAMA. 2025. View source
8. USPSTF recommendations on calcium and vitamin D supplementation for fracture prevention. Summary by The OBG Project. View source
9. LIFTMOR trial: high-intensity resistance and impact training in postmenopausal women with low bone mass. Summary in Healio. View source
10. Beck BR, Weeks BK, Weis LJ, Harding AT, Horan SA, Watson SL. Brief high intensity exercise improves bone, posture and functional risk factors for falling in postmenopausal women with osteopenia and osteoporosis: the LIFTMOR trial. Osteoporos Int. 2017. View source
11. High-intensity exercise did not cause vertebral fractures and improves thoracic kyphosis in postmenopausal women with low to very low bone mass: the LIFTMOR trial. View source
12. Cauley JA, Robbins J, Chen Z, et al. Effects of estrogen plus progestin on risk of fracture and bone mineral density: the Women's Health Initiative randomized trial. JAMA. 2003;290:1729–1738. View source
13. Creatine in women's health: where the research stands in 2026 (bone density meta-analyses). View source