PFS and bone loss: what do studies show?

Worried finasteride has thinned your bones? In the trials that scanned men’s bones while they took it, bone density didn’t fall. Other symptoms can last after stopping, though. This is called post-finasteride syndrome, or PFS.

Nobody has yet measured bone density in people with PFS. So the trials can’t tell you what happens in your body if your symptoms have lasted.

Ryan, who shared his story with us, lists loss of bone density among the symptoms he lives with. “My bones have become brittle and fragile,” he writes.

His account is one person’s experience, not proof that finasteride caused it.

What did the bone scans show, and what can you do if you’re worried about your own bones?

Does finasteride cause bone loss?

The trials that measured it found no bone loss. Finasteride lowers DHT, a hormone made from testosterone, and androgens play a part in bone health. That’s why researchers checked.

The longest study followed men with an enlarged prostate who took finasteride 5 mg or a dummy pill. Bone scans of the lower spine were repeated over four years. At the end, bone density was about the same in both groups.

A second trial gave healthy men aged 18 to 55 finasteride, dutasteride or a dummy pill for a year. It found that bone density and blood markers of bone turnover didn’t change, even though DHT fell sharply. Bones were scanned again six months after the tablets stopped.

Both trials were small, a few dozen men in each group, and both used the 5 mg dose. Neither looked for people whose symptoms lasted after stopping.

Has any study linked finasteride to osteoporosis?

One has. It looked at insurance records in Taiwan for older men with an enlarged prostate. Men who were later diagnosed with osteoporosis were somewhat more likely to have used finasteride, and the link was stronger at higher doses.

A records study like this shows a pattern, not a cause. It can’t measure bone directly, and men who see doctors more often may simply get diagnosed more often. The trials that did scan bones point the other way.

So the evidence for finasteride as a whole is mixed but mostly reassuring. It says little about the smaller group whose symptoms continue after stopping.

Has anyone studied bone in people with PFS?

Not yet. We found no published study that has measured bone density in people with PFS.

The 2022 diagnostic criteria don’t mention bone. They describe PFS as more than sexual problems: cognitive problems, depression and suicidal thoughts can happen with or without sexual changes.

The UK Propecia leaflet doesn’t list bone loss either. It does list sexual problems that persist after treatment ends.

Nobody knows yet whether bone changes are part of PFS for some people. Reports like Ryan’s are how a question like this first gets noticed.

What can I do?

These medicines help many people. If you have side effects, that’s a decision for you and your prescriber.

If your mood drops or you have suicidal thoughts, the Propecia leaflet says to stop taking it and contact your doctor as soon as possible. The Samaritans are on 116 123, free, at any hour.

Thinning bones often give no warning. The NHS osteoporosis page says the first sign is often a broken bone after a minor fall. If that has happened to you, tell your GP. They can assess your risk and may refer you for a bone density (DEXA) scan.

For bone health in general, the NHS advises regular weight-bearing, strengthening and balance exercise. It also advises enough calcium and vitamin D, and not smoking.

Write down your dates for your GP: “Finasteride 1 mg from May 2018, last tablet March 2024. Broke my wrist in a small fall in 2026.” Many people say it took time to be taken seriously. Our guide to which doctor to see for PFS can help.

Report it: it helps everyone

A doctor’s note helps you. A report to the medicines regulator helps everyone else: it is how patterns get noticed.

• No proof needed. A suspicion is enough, even years after stopping.
• Where: the Yellow Card scheme in the UK, MedWatch in the US.
• Use the right words. If symptoms continued after stopping, write Post 5-alpha-reductase inhibitor syndrome (MedDRA 10082430).

Our reporting guide walks you through it

What else do people ask?

Does dutasteride affect bone density? In the one-year trial of healthy men, dutasteride didn’t change bone density either. No study has looked at bone in people whose symptoms lasted after stopping dutasteride.

Don’t men need DHT for strong bones? The authors of the one-year trial concluded that DHT in the blood doesn’t seem to play a clinically important role in bone mass in healthy men.

Should I stop finasteride to protect my bones? That’s a decision for you and your prescriber. Bone loss isn’t listed as a side effect in the UK leaflet. If you have other side effects, the leaflet tells you what to do.

Ryan described his bones in his own words because nobody else had measured them. If you’ve had a bone scan or a fracture since finasteride, report it alongside your other symptoms of PFS.

Sources

1. Matsumoto AM, Tenover L, McClung M and colleagues. The long-term effect of specific type II 5alpha-reductase inhibition with finasteride on bone mineral density in men: results of a 4-year placebo controlled trial. J Urol 2002;167(5):2105-8. 157 men aged 46 to 76 with benign prostatic hyperplasia, finasteride 5 mg or placebo; lumbar spine DXA in 117 men. Mean BMD after 4 years 1.14 g/cm² on finasteride, 1.13 g/cm² on placebo.
2. Amory JK, Anawalt BD, Matsumoto AM and colleagues. The effect of 5alpha-reductase inhibition with dutasteride and finasteride on bone mineral density, serum lipoproteins, hemoglobin, prostate specific antigen and sexual function in healthy young men. J Urol 2008;179(6):2333-8. 99 men aged 18 to 55: dutasteride 0.5 mg (33), finasteride 5 mg (34) or placebo (32) for 1 year; BMD at baseline, 1 year and 6 months after stopping. No significant effect on BMD or bone turnover markers. Authors’ conclusion: circulating DHT “does not appear to have a clinically significant role in modulating bone mass” in normal men.
3. Lin WL, Hsieh YW, Lin CL and colleagues. A population-based nested case-control study: the use of 5-alpha-reductase inhibitors and the increased risk of osteoporosis diagnosis in patients with benign prostate hyperplasia. Clin Endocrinol (Oxf) 2015;82(4):503-8. Taiwanese National Health Insurance claims, 1,352 osteoporosis cases and 5,387 controls; adjusted odds ratio 1.52 (95% CI 1.01 to 2.30) for finasteride use; 1.68 at higher doses. Diagnoses from claims, not bone scans.
4. Propecia 1 mg film-coated tablets, patient information leaflet and summary of product characteristics, electronic medicines compendium (emc), checked 5 November 2026. Neither lists bone loss. Leaflet section 4: “persistent difficulty having an erection after discontinuation of treatment”, persistent decrease in sex drive and persistent problems with ejaculation. Section 2, on mood changes: stop taking Propecia and contact your doctor as soon as possible.
5. Healy D, Bahrick A, Bak M and colleagues. Diagnostic criteria for enduring sexual dysfunction after treatment with antidepressants, finasteride and isotretinoin. Int J Risk Saf Med 2022;33(1):65-76. Section 5: for finasteride, cognitive impairment, depression and suicidality can occur with or without sexual difficulties. The full text doesn’t mention bone.
6. NHS, Osteoporosis, page last reviewed 29 October 2026. No symptoms before a fracture in many people; GP may refer for a DEXA scan; exercise, calcium, vitamin D and not smoking.
7. Ryan’s story on our site: The Silent Struggle of PFS: Ryan’s Story, published 3 September 2024, consent confirmed 10 October 2026.