Report finasteride side effects to the FDA

You can report finasteride side effects yourself to the FDA, the US medicines regulator, on its MedWatch form. If they continued after you stopped, name the condition in your description: post-finasteride syndrome (PFS), which the regulators’ dictionary calls Post 5-alpha-reductase inhibitor syndrome.

The form has no list of conditions to pick from. FDA staff turn what you write into terms from that dictionary, MedDRA, so the words you choose matter.

Gary got his finasteride through a telehealth hair clinic. It was a solution for his scalp, which he calls “the compound”. He asked about side effects first, he says, and the answer was: “Not topical.” Topical means it goes on the skin.

Play video: Gary on what he asked before topical finasteride

He used it for about two months. He describes twitching, burning hands and broken sleep, and says things got worse after he stopped. At first he didn’t link any of it to the solution: “I wasn’t taking a drug.”

How do I report finasteride side effects to the FDA?

Use MedWatch, the FDA’s reporting programme. It covers Propecia, Proscar and generic tablets, and scalp solutions that a pharmacy makes up.

Have your pack and dates to hand. On the MedWatch reporting site, choose Consumer/Patient (FDA Form 3500B).

1. Say what kind of problem it was. The first question has an option for side effects: “Were hurt or had a bad side effect”.

2. Answer the question about outcomes. “Did any of the following happen?” lists what the problem led to. It has no star. Tick only what happened to you.

3. Give the date it began. The date box wants the month first: 05/01/2023 is 1 May 2023.

4. Describe it in your own words. “Tell us what happened and how it happened” has a star. Name the condition and its MedDRA code there, in English: “Post 5-alpha-reductase inhibitor syndrome (MedDRA 10082430). Finasteride 1 mg daily from March 2022, last tablet June 2023. Since May 2023, low sex drive and erection problems. No change since my last tablet. No sexual problems before finasteride. No other medicines.”

5. Choose product or device. “Please select the cause of the problem” has a star. The option “For a problem with a product” covers prescription medicines. Then choose Next.

6. Name the medicine. Type the name as it appears on the pack, for example “Finasteride 1 mg tablets”. The form also asks how you used it, for example by mouth or on the skin.

7. Give your dates of use. Enter when you started and stopped, for example 03/15/2022 and 06/20/2023. The form takes a best estimate.

8. Answer the two questions about stopping. The form asks whether the problem stopped after you reduced the dose or stopped the medicine, and whether it returned if you started again. Answer with what happened to you.

9. Add your details and send. The Patient page has no starred box. The Reporter page needs your first and last name. A tick box there keeps your identity from the company that makes the medicine. Choose Submit, then save the PDF copy.

You can also post or fax the paper version, Form FDA 3500B, or phone 1-800-FDA-1088. Our antidepressant guide uses the same form. In the UK? Use the Yellow Card scheme instead.

What if my finasteride was compounded or bought online?

Report it the same way. The FDA has an alert, dated April 2025, about compounded finasteride: finasteride that a pharmacy makes up for use on the scalp. It says some compounders and telemedicine platforms market it.

No finasteride for the skin is FDA-approved, the alert says, and the FDA doesn’t check compounded medicines before they’re sold.

The alert counted 32 reports. In some, patients said a prescriber had told them there was no risk “because the product was topical”. The FDA encourages patients to report problems with compounded medicines.

The form has room for this. Its Product page asks which company makes or compounds the product, and lists “Compounded product” as a type. There’s a box for the website if you bought it online.

Play video: MedWatch Minute for Consumers

Does it matter what I write in the description?

Yes. FDA staff read your description and give the report its MedDRA codes, their 2025 guide says. Those codes are how they find reports again.

MedDRA has a term for PFS: Post 5-alpha-reductase inhibitor syndrome, code 10082430. Use the dictionary’s own words and it’s clear which condition you mean.

The FDA’s database holds reports under that term. A 2025 study counted 166 for finasteride.

Detail counts too. Very short descriptions are unlikely to give enough for a meaningful review, the guide says.

1

The term

With its code, 10082430.

2

Medicine, dose and dates

As on the pack.

3

When it began

Month and year.

4

What happened after stopping

In your own words.

5

Other medicines and conditions

Or “none”.

What can I do if I think I have PFS?

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

If you think you have PFS, tell your doctor. Propecia’s US leaflet says to mention any side effect that bothers you or doesn’t go away.

Bring the dates you started and stopped. You can report without a doctor agreeing.

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 my doctor have to send the report? No. The FDA suggests taking the form to your doctor, who can add details from your record. “Your health care provider is NOT required to report to the FDA,” its MedWatch page adds. You can fill in the form yourself.

Is it too late if I stopped years ago? As of October 2026, the MedWatch form and pages set no deadline. The form tells you to send the report even if you don’t have all the information. Our article on reporting years later has more.

Can I look up finasteride reports? Yes. As of March 2026 the FDA’s AEMS public dashboard, long known as FAERS, lets anyone search reports by medicine. A report doesn’t prove the medicine caused the problem, the FDA cautions, and counts can’t show how often it happens.

Some patients in the FDA’s alert reported being told what Gary says he was told: no side effects, because it was topical. The FDA knows because those patients wrote it in their reports. Report it in your own words, and name the condition.

Sources

1. Propecia (finasteride 1 mg), US prescribing information and Patient Information, Organon. DailyMed, US National Library of Medicine, opened 12 October 2026. The prescribing information was revised in August 2022 and the Patient Information in November 2023. Under side effects reported in general use, the Patient Information lists “decrease in sex drive that continued after stopping the medication”. It lists erection and ejaculation problems that continued after stopping in near-identical words. “Tell your healthcare provider if you have any side effect that bothers you or that does not go away.” It ends: “You may report side effects to FDA at 1-800-FDA-1088.” Section 6.2 says these reactions were “reported voluntarily from a population of uncertain size”. So it is not always possible to estimate how often they happen, or to establish that the drug caused them. Proscar (finasteride 5 mg) has its own label.
2. US Food and Drug Administration, FDA alerts health care providers, compounders and consumers of potential risks associated with compounded topical finasteride products, content current as of 22 April 2025, opened 12 October 2026. “The agency is aware of some compounders and telemedicine platforms that market topical formulations of finasteride”, alone or with other ingredients such as minoxidil. The alert names no company. “Currently, there is no FDA-approved topical formulation of finasteride.” It counts 32 cases reported to the FDA Adverse Event Reporting System between 2019 and 2024. “Most of the reports FDA has received state the adverse events continued to persist after product discontinuation.” Some patients reported being told by prescribers “that there was no risk of any adverse event because the product was topical”. Compounded drugs are not FDA-approved, “which means FDA has not evaluated their safety, effectiveness or quality prior to marketing”. The FDA “encourages consumers, health care providers and compounders to report” problems with compounded drugs, including compounded topical finasteride, to MedWatch.
3. US Food and Drug Administration, Reporting Serious Problems to FDA, content current as of 26 September 2025, opened 12 October 2026. “You are encouraged to take the reporting form to your doctor.” “Your health care provider is NOT required to report to the FDA. In these situations, you may complete the Online Reporting Form yourself.” The page lists Form FDA 3500B as the consumer version of the form.
4. US Food and Drug Administration, MedWatch Online Voluntary Reporting Form, opened 12 October 2026. It offers two routes: Health Professional (FDA Form 3500) and Consumer/Patient (FDA Form 3500B). Its Frequently Asked Questions page gives the minimum needed: a description of the problem, the name of the product and the reporter’s name. Lot number and expiry date “should be reported when available but are not required”. The FDA will not disclose your identity to the manufacturer “if requested in the form”. A copy can be saved as a PDF from the confirmation page.
5. US Food and Drug Administration, Form FDA 3500B, MedWatch Consumer Voluntary Reporting, version 09/2025, eight pages (OMB No. 0910-0291, expires 30 September 2027), downloaded 12 October 2026. “Fill in as much information as possible and send in the report even if you do not have all the information.” Section A asks for the date the problem occurred and sets no deadline. Section C asks for the “Name(s) of the company that makes (or compounds) the product”. Its product types include “Compounded product (By a Pharmacy or an Outsourcing Facility)”. It has a box headed “Website (If purchased online)”, and asks for the lot number and the expiry date. It asks how the product was taken or used “(For example, by mouth, injection, or on the skin)”. The paper form goes by post or fax, to the address and fax number on its last page. The phone number is from FDA 101, content current as of 9 November 2020.
6. The online form’s wording. We read the first page (“About Problem”) on the live form on 12 October 2026, entering nothing; the form opens its later pages only once the starred boxes on that page are filled. The later pages were read from our own screen recording of a finasteride report on MedWatch, committed 2 September 2026, and checked against Form FDA 3500B (09/2025). Starred fields: “Tell us what happened and how it happened”, the cause of the problem, the name of the product, the reporter’s first and last name, and the reCAPTCHA. The “About Patient” page has no starred field. Dates are entered as mm/dd/yyyy. Dates of use may be a “best estimate”.
7. Potter E, Reyes M, Naples J, Dal Pan G. FDA Adverse Event Reporting System (FAERS) Essentials: a guide to understanding, applying, and interpreting adverse event data reported to FAERS. Clin Pharmacol Ther 2025;118(3):567-582. The authors work in the FDA’s Office of Surveillance and Epidemiology. “For reports that the public submits directly to the FDA, FDA staff abstract and code AE terms.” FDA staff “retrieve ICSRs coded with the MedDRA term signifying the AE term(s) of interest”. “Very short narratives are unlikely to contain sufficient details for a meaningful review.” The most useful elements of a report include time to onset, the product’s dose, lot number and dates, other medicines and existing medical conditions. The response to stopping the drug is on the list too. The paper also says reports cannot give the incidence of a side effect, and that not every report is read individually.
8. Zhong X, Yang Y, Wei S, Liu Y. Multidimensional assessment of adverse events of finasteride: a real-world pharmacovigilance analysis based on FDA Adverse Event Reporting System (FAERS) from 2004 to April 2024. PLoS One 2025;20(3):e0309849. It analysed 11,557 reports, from January 2004 to March 2024, in which finasteride was the main suspected medicine. Of these, 166 carried the preferred term “Post 5-alpha-reductase inhibitor syndrome”. The study counts reports. It cannot show how often the condition happens or that finasteride caused it. It does not say who sent those reports or who coded them.
9. MedDRA term as listed in our reporting data: Post 5-alpha-reductase inhibitor syndrome (10082430). As of 12 October 2026 we found no FDA document that says how a report naming this term is coded.
10. US Food and Drug Administration, FDA Adverse Event Monitoring System (AEMS) Public Dashboard, content current as of 11 March 2026. The page is headed “Formerly FDA Adverse Event Reporting System (FAERS)”. “Existence of a report does not establish causation”; “Rates of occurrence cannot be established with reports”.
11. Moral Medicine, Post Finasteride Syndrome - Gary’s Experience with Topical Finasteride, 17 May 2023 (the title is the channel’s). Our page plays an extract, 3:27 to 4:00; the views are his own. A “telehealth” hair clinic, and “the compound” sent to him from Florida (2:06 to 2:38). “Are there any side effects?” and “Not topical” (3:34 to 3:47). About two months of use, from November to early January (4:32 to 5:06). “I was not attributing any symptoms to a topical solution” and “I wasn’t taking a drug” (5:11). Burning arms and hands (6:02, 8:01), twitching and sleep (8:22 to 9:14), and “they went down quick” after stopping (7:50). Quotes from the YouTube captions. His story on our site: Gary’s experience with topical finasteride.
12. US Food and Drug Administration, MedWatch Minute for Consumers, 20 January 2022, 80 seconds. “Give as much detail as possible in your report, such as the product’s name, lot number and expiration date.”
13. Picture: the first page of the MedWatch consumer reporting form (Form FDA 3500B online), a still from our own screen recording, committed 2 September 2026. No box is ticked.