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Finasteride

A once-daily tablet that blocks the enzyme converting testosterone to DHT, the androgen associated with pattern hair loss.

Not for

• Women. Finasteride is not indicated for use in women, and it is not approved for women of any age.
• Children.
• Anyone who has had an allergic reaction to finasteride or dutasteride.

Handling

• A woman who is pregnant or may become pregnant must not handle crushed or broken tablets. Finasteride can affect the development of the external genitalia in a male fetus. Whole tablets are coated, which prevents contact with the active during ordinary handling.

Common effects

• Reduced sex drive, difficulty getting or keeping an erection, and reduced volume of ejaculate. These were reported by a small share of men in trials and resolved for most who continued or stopped.
• Breast tenderness or enlargement, and testicular pain.

Serious effects

• Sexual side effects that continue after stopping have been reported after marketing.
• Depression and, in reports, thoughts of self-harm.
• Breast cancer in men has been reported in people taking finasteride.
• Allergic reactions, including rash, hives, itching, and swelling of the lips, tongue, face or throat.

Get medical help if

• A lump, pain, or discharge in the breast.
• Swelling of the lips, tongue, face or throat, or trouble breathing or swallowing.
• A change in mood, or thoughts of harming yourself.

Tell your provider

• Finasteride lowers the PSA reading used in prostate screening. Tell anyone ordering a PSA test that you take it, so the result is read correctly.
• Do not donate blood while taking finasteride, and wait at least one month after your last dose.

Sources

1. Finasteride 1 mg tablets, FDA prescribing information. US Food and Drug Administration. FDA-approved labeling, DailyMed
2. Finasteride 1 mg tablets, FDA prescribing information, warnings and precautions. US Food and Drug Administration. FDA-approved labeling, DailyMed
3. Finasteride 1 mg tablets, FDA prescribing information, clinical pharmacology. US Food and Drug Administration. FDA-approved labeling, DailyMed

Finasteride, applied to the scalp

Finasteride delivered onto the scalp rather than swallowed. Some of it is still absorbed, so the systemic cautions for the tablet apply.

Not for

• Women. Finasteride is not indicated for use in women, and it is not approved for women of any age.
• Children.
• Anyone who has had an allergic reaction to finasteride or dutasteride.

Handling

• A woman who is pregnant or may become pregnant must not handle this product or come into contact with it on your skin, hair or pillow. Finasteride can affect the development of the external genitalia in a male fetus.
• Wash your hands after applying, and let the scalp dry fully before it touches anyone or anything.

Common effects

• Itching, dryness, flaking or redness where it is applied.
• The systemic effects reported for the tablet, including reduced sex drive and difficulty getting or keeping an erection, have also been reported with topical use.

Serious effects

• Sexual side effects that continue after stopping have been reported after marketing.
• Depression and, in reports, thoughts of self-harm.
• Allergic reactions, including rash, hives, itching, and swelling of the lips, tongue, face or throat.

Get medical help if

• Swelling of the lips, tongue, face or throat, or trouble breathing or swallowing.
• A change in mood, or thoughts of harming yourself.
• A lump, pain, or discharge in the breast.

Tell your provider

• Finasteride lowers the PSA reading used in prostate screening. Tell anyone ordering a PSA test that you use it.
• Anyone in your household who is pregnant or may become pregnant, so a provider can weigh the transfer risk with you.

Sources

1. Finasteride 1 mg tablets, FDA prescribing information. US Food and Drug Administration. FDA-approved labeling, DailyMed
2. Finasteride 1 mg tablets, FDA prescribing information, warnings and precautions. US Food and Drug Administration. FDA-approved labeling, DailyMed
3. Finasteride 1 mg tablets, FDA prescribing information, clinical pharmacology. US Food and Drug Administration. FDA-approved labeling, DailyMed

Minoxidil, applied to the scalp

A solution applied to the scalp. Topical minoxidil is sold over the counter for hair regrowth, which is the wording of its approved labeling.

Not for

• Anyone whose hair loss is sudden, patchy, or came with a rash, pain or scaling, until a provider has looked at it.
• Anyone who has had an allergic reaction to minoxidil or propylene glycol.

Handling

• Wash your hands after applying, and let the scalp dry before it touches a pillow or another person. Solution that transfers can grow hair where you did not put it.
• Keep it away from children and pets. It is dangerous if swallowed, and it is toxic to cats.

Common effects

• Itching, dryness, flaking or redness where it is applied.
• More shedding during the first few weeks, as follicles reset into a new growth cycle.
• Unwanted hair on the face if the solution runs or transfers.

Serious effects

• Contact dermatitis that does not settle.
• Absorbed minoxidil can, rarely, cause the heart and fluid effects listed for the tablet.

Get medical help if

• Chest pain, a fast heartbeat, faintness or dizziness.
• Sudden unexplained weight gain, or swollen hands or feet.
• Scalp redness or irritation that keeps getting worse.

Tell your provider

• Any heart condition, and any other product you put on your scalp.

Sources

1. Minoxidil topical solution and foam, FDA-approved over-the-counter labeling. US Food and Drug Administration. FDA-approved OTC labeling, DailyMed
2. Randolph M, Tosti A. Oral minoxidil treatment for hair loss: a review of efficacy and safety. Journal of the American Academy of Dermatology. J Am Acad Dermatol 2021;84(3):737-746

Minoxidil, taken by mouth

A tablet that widens blood vessels. In hair follicles it is understood to lengthen the growing phase.

Minoxidil tablets are approved to treat severe high blood pressure, not hair loss. Prescribing them for hair loss is off-label. A provider may do that, and should tell you why.

Boxed warning. Minoxidil tablets carry an FDA boxed warning. Fluid can collect around the heart and, in some cases, compress it (pericardial effusion progressing to tamponade). Chest pain from angina can get worse. The tablets can cause salt and water retention that leads to heart failure. In the approved use they are given under close supervision, usually alongside a medicine to slow the heart and a diuretic.

Not for

• Anyone with a pheochromocytoma.
• Anyone who has had an allergic reaction to minoxidil.

Common effects

• Hair growth in places you did not intend, most often on the face, arms and back. This is the most frequently reported effect at hair-loss doses.
• Fluid retention, which usually shows first as puffy ankles or a quick gain in weight.
• A faster heartbeat, lightheadedness, or headache.

Serious effects

• Fluid around the heart, which can become an emergency.
• Worsening angina.
• Heart failure from salt and water retention.

Get medical help if

• Shortness of breath, especially lying down.
• Chest pain, or a heartbeat that stays fast.
• Swelling of the hands, feet or face, or a weight gain of more than 2 kg (about 5 lb) in a few days.
• Fainting or near-fainting.

Tell your provider

• Any heart, kidney or blood-pressure condition, and every blood-pressure medicine you take.

Sources

1. Minoxidil tablets USP, FDA prescribing information, boxed warning. US Food and Drug Administration. FDA-approved labeling, DailyMed
2. Randolph M, Tosti A. Oral minoxidil treatment for hair loss: a review of efficacy and safety. Journal of the American Academy of Dermatology. J Am Acad Dermatol 2021;84(3):737-746
3. Randolph M, Tosti A. Oral minoxidil treatment for hair loss: a review of efficacy and safety. Journal of the American Academy of Dermatology. J Am Acad Dermatol 2021;84(3):737-746

Biotin

A B vitamin used in keratin production. Evidence that supplementing it improves hair growth in people who are not deficient is limited.

Common effects

• Biotin is generally well tolerated.

Serious effects

• Biotin interferes with laboratory immunoassays. It can make a troponin result (the test used to diagnose a heart attack) read falsely low, and it can distort thyroid results in both directions.

Tell your provider

• Tell any clinician and any lab that you take biotin before a blood test, and ask whether to stop it beforehand.

Sources

1. The FDA warns that biotin may interfere with lab tests. US Food and Drug Administration. FDA safety communication
2. Patel DP, Swink SM, Castelo-Soccio L. A review of the use of biotin for hair loss. Skin Appendage Disorders. Skin Appendage Disord 2017;3(3):166-169