Thinning hair is a fact of life for most men and many women as they age — over 80 percent of men, and just under 50 percent of women, will experience hair loss, according to NYU Langone Health. Many people turn to topical treatments like creams, shampoos, oils, and gels that promise to regrow hair or stop the problem from getting worse.

These treatments typically contain minoxidil, and they may be referred to as topical minoxidil more broadly.

Minoxidil is an ingredient that has been used for decades and is generally considered safe and well tolerated. But its efficacy is variable, says Sandeep Sattur, MD, a hair restoration surgeon at the HairRevive Centre for Hair Restoration and Skin Rejuvenation in Mumbai, India. Also, this form of minoxidil can come with some unpleasant side effects, among other downsides.

Now, for potentially better treatment, some dermatologists are now prescribing minoxidil orally to address hair loss. Although the U.S. Food and Drug Administration (FDA) hasn’t approved these pills for hair loss, doctors are free to prescribe oral minoxidil for this off-label use. Here’s what you need to know if you or a loved one is facing hair loss and is curious about whether minoxidil could be an option.

1. Topical Minoxidil Can Help Retain and Grow Hair, But It’s Not Perfect

The FDA cleared the first topical version of minoxidil to treat male pattern baldness in the late 1980s. Since then, the FDA has also approved minoxidil for female pattern hair loss, allowed it to be made in higher concentrations, and cleared it for over-the-counter sales without a prescription.

In a nutshell, topical minoxidil helps stimulate hair growth or slow balding when applied to the scalp once or twice a day.

These scalp treatments usually contain 2 or 5 percent minoxidil as the active ingredient. They’re available without a prescription and work best for recent hair loss in people under 40, according to MedlinePlus.

Several clinical trials of topical minoxidil in men and women have demonstrated it helps increase hair thickness in areas where hair loss was observed, per data from the Center for Drug Evaluation and Research (PDF). Some studies suggest that the extra strength version (which uses a 5 percent concentration of the drug) is more effective than the original formula (which uses a 2 percent concentration).

But as mentioned, topical minoxidil has its disadvantages. For instance, results may take months to see, and any new hair growth disappears when you stop treatment. Also, topical minoxidil doesn’t work for all types of hair loss — for example, it’s unlikely to help patients with pattern baldness, particularly if they’ve lived with the condition for a while before initiating treatment. And it can have side effects ranging from unpleasant scalp stickiness to itching, rashes, and inflammation, per Mayo Clinic.

2. Oral Minoxidil Was Originally Used to Treat High Blood Pressure

Oral minoxidil actually precedes topical minoxidil, and was initially approved as a prescription drug for severe hypertension, or high blood pressure, per Mayo Clinic. Originally approved by the FDA in the late 1970s as a pill to treat severe hypertension, or high blood pressure, minoxidil pills often had an unexpected side effect: excessive hair growth. Drug developers quickly saw potential in this side effect and reformulated minoxidil into a topical treatment for hair loss, as the American Academy of Dermatology Association (AAD) notes.

“Nowadays, it is rather uncommon to treat hypertension with minoxidil,” says Juan Jimenez Cauhe, MD, a dermatologist at Ramon y Cajal University Hospital and a trichologist at Grupo Pedro Jaen Clinic, both in Madrid. It’s only recommended for severe hypertension cases when patients don’t respond to other medicines or when people have kidney failure, according to the American Heart Association.

“Within the last seven years, it has increasingly been used off-label for different types of hair loss at low doses,” he adds. More on that next.

3. Oral Minoxidil Is an ‘Off-Label’ Treatment for Hair Loss

The term “off-label,” or “unapproved,” can mean different things, per the FDA. It could mean providers prescribe a drug in a different form (for example, orally versus topically), or at a different dosage, or to treat a disease or condition that it’s not FDA-approved for.

Minoxidil is currently FDA-approved as an oral medication to treat high blood pressure, and as a topical medication to treat hair loss. But the drug is not currently FDA-approved to treat hair loss when taken orally — and so any prescription for this purpose is considered “off-label.”

4. The Research on Taking Minoxidil Orally for Hair Loss Is Lacking

So far, there isn’t enough high-quality research to support oral minoxidil for hair loss. But a handful of small studies suggest that oral minoxidil can help treat hair loss, and may be more effective for some patients than topical treatments, Dr. Sattur says.

For example, one small observational study involving 100 women experiencing female pattern hair loss suggested that a daily pill containing 0.25 milligrams (mg) minoxidil and 25 mg spironolactone was safe and effective in treating the condition. But the study did not use a control group, so it’s not clear whether these results are due to the medication.

A later review, published in the Journal of the American Academy of Dermatology in July 2020, looked at 17 studies involving 634 patients. The review suggested that oral minoxidil was a generally effective and well-tolerated alternative to topical minoxidil, though researchers add that larger, controlled studies are needed.

5. There’s No Standard Dosage for Oral Minoxidil

Sattur points out that most of these studies looked at doses ranging from 0.25 mg to 5 mg — less than the doses used for hypertension. (Doses for hypertension usually range from 5 to 40 mg for adults and children over 12 years old.)

“Whatever limited small sample studies have been published do not have a consensus on the optimal dose,” Sattur says — a drawback that’s common to all off-label drugs. The lack of a standard dose means that it’s unclear what amount of minoxidil (if any) is safe when taken for an off-label purpose.

6. Minoxidil Pills Can Carry Serious Side Effects

Side effects are generally less of a concern with topical treatments, as they target a single area of the body, than with systemic medications like pills, which act beyond just a single body part.

Common side effects of topical minoxidil can include itching or skin rashes on the scalp, while more rare side effects can include acne, inflammation, swelling, blurred vision, or chest pain, according to Mayo Clinic.

But the safety picture of oral minoxidil for hair loss is far less clear, because it hasn’t been tested in the type of rigorous clinical trials required for FDA approval. For example, it’s unknown whether oral minoxidil in low doses for hair loss may negatively impact blood pressure in people who don’t have hypertension, Sattur says: “It will have to be tailored in every patient based on the changes in the blood pressure and cardiovascular system.”

What we do know is that minoxidil pills carry a black box warning from the FDA (PDF), as they may raise your risk of pericardial effusion, which is the clinical name for excessive fluid buildup around the heart, per Mayo Clinic.

Other side effects seen in some patients taking lower doses of oral minoxidil for hair loss include dizziness, heart palpitations, and fluid retention, adds Dr. Jiménez Cauhé. While these side effects should clear up when patients stop taking the pills, the potential for these issues is one reason why patients should get them prescribed by a medical provider who has a full picture of patients’ current medical conditions and medical history, Jiminez-Cauhe adds.

7. Minoxidil Is Not Safe to Use During Pregnancy

Women who are pregnant or breastfeeding shouldn’t use minoxidil, cautions the AAD, as traces of the drug can pass into breast milk. Several other medications for hair loss, including finasteride, aren’t FDA-approved for female pattern hair loss but can be used for this purpose as long as patients aren’t pregnant or planning to become pregnant, according to the AAD.

8. Minoxidil Isn’t Your Only Treatment Option for Hair Loss

Patients have a wide variety of treatment options for pattern hair loss besides minoxidil, according to the AAD. Treatment options differ for men and women, in part because some interventions can cause facial hair and others aren’t recommended for people who are pregnant or breastfeeding.

Options for treating pattern baldness in addition to minoxidil can include, according to the AAD:

Finasteride A prescription pill that can slow down hair loss in most men taking it
Hair Transplants A procedure that moves hair plugs from one part of the scalp to another
Platelet-Rich Plasma A procedure that separates plasma out of patients’ blood to inject into scalp, and can be done alone or combined with hair transplants

9. Topical Minoxidil Remains the Gold Standard for Treating Hair Loss

Anyone considering treatment for hair loss for the first time should start with FDA-approved options before considering minoxidil pills, dermatologists say. That includes topical minoxidil, which is sold as brand-name Rogaine products and in a variety of generic versions.

“The first step for a patient considering low dose oral minoxidil should be seeking a dermatologist with experience in diagnosing hair disorders,” says Dmitri Wall, MD, a consultant dermatologist and hair transplant surgeon at St. James’ Hospital in Dublin.

“In my opinion, the risk-benefit ratio of oral minoxidil as compared to topical minoxidil — and the fact that the available evidence for oral minoxidil is not of very high quality — does not justify use of oral minoxidil routinely in management of pattern hair loss,” Sattur says. “Topical minoxidil is still the first line therapy.”