Short answer: The minoxidil tablet label, which is for high blood pressure only, reports thicker, darker body hair (hypertrichosis) in about 80% of patients within 3 to 6 weeks, ECG T-wave changes in about 60%, and temporary swelling in 7%. Its boxed warning says minoxidil can cause pericardial effusion, sometimes progressing to tamponade, and can worsen angina, so it is reserved for hard-to-treat high blood pressure.
What Minoxidil Tablets is approved for: Minoxidil tablets are labeled for high blood pressure only: severe hypertension that causes symptoms or organ damage and is not controlled by maximum doses of a diuretic plus two other blood pressure drugs (Indications and Usage). Use in milder high blood pressure is not recommended. The label states that using minoxidil tablets in any formulation to promote hair growth is not an approved indication (Precautions, Unapproved Use).
Source
Minoxidil Tablets, USP, prescribing information and Patient Information. Par Health USA. DailyMed, version published June 15, 2026. DailyMed setid 8f3800f0-b6da-4dfe-8c32-39bb5eb0262a
WARNINGS
Minoxidil tablets contain the powerful antihypertensive agent minoxidil, which may produce serious adverse effects. It can cause pericardial effusion (fluid around the heart), occasionally progressing to tamponade, and angina may be made worse. Minoxidil should be reserved for people with high blood pressure who do not respond adequately to maximum therapeutic doses of a diuretic and two other blood pressure drugs. In experimental animals, minoxidil caused several kinds of heart muscle lesions and other cardiac effects. Minoxidil must be given under close supervision, usually together with a beta-blocker to prevent a fast heart rate and extra heart workload, and usually with a diuretic, often a loop diuretic, to prevent serious fluid build-up. People with malignant hypertension and those already taking guanethidine should be hospitalized when minoxidil is first given, so they can be monitored for too rapid or large drops in blood pressure on standing.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Minoxidil Tablets.
| Reaction | How often the label reports it |
|---|---|
| Hypertrichosis (elongation, thickening and darker pigment of fine body hair) | About 80% of patients, developing within 3 to 6 weeks |
| ECG T-wave changes | Approximately 60% of patients; usually disappear with continued treatment |
| Edema despite diuretic treatment (non-dialysis patients) | Approximately 10% (reversible) |
| Temporary edema in patients not edematous at the start | 7% |
| Fall in hematocrit, hemoglobin and red cell count (hemodilution) | About 7% at first, then recover to pretreatment levels |
| Pericardial effusion, occasionally with tamponade | About 3% of patients not on dialysis |
| Serum creatinine rise | Average of 6%, later declining to pretreatment levels |
| Skin rash (possible hypersensitivity) | Less than 1% |
| Breast tenderness | Less than 1% |
The label gives these rates in its text; there was no placebo comparison. Most patients were also taking a diuretic and a beta-blocker or similar medicine.
Extra hair usually shows first on the temples, between the eyebrows, between the hairline and eyebrows, or the upper cheek, later the back, arms, legs and scalp. After stopping, new growth stops, but 1 to 6 months may be needed to return to how things looked before. No hormone abnormality was found to explain it.
Also reported: rashes including rare bullous eruptions, toxic epidermal necrolysis and Stevens-Johnson syndrome; rare low platelets and white cells; nausea and/or vomiting; and variable rises in alkaline phosphatase.
Minoxidil lowered supine diastolic blood pressure by 20 mmHg, or to 90 mmHg or less, in approximately 75% of patients, most of whom had blood pressure that other drugs could not control.
A smaller weight gain of 2 to 3 pounds often occurs when treatment is started and may be lost with continued treatment.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Who should not take it. People with pheochromocytoma, because minoxidil may stimulate the tumor to release catecholamines, and people with a past allergy to any of its components.
Salt and water retention. Minoxidil usually must be given with a diuretic, almost always a loop diuretic, to prevent fluid retention and possible heart failure. Without one, several hundred milliequivalents of salt and matching water can be retained within a few days. Body weight is watched closely.
Fast heart rate and angina. Minoxidil raises heart rate, and angina may worsen or appear for the first time. A beta-blocker or other sympathetic suppressant, effective around the clock, usually prevents this.
Pericarditis, pericardial effusion and tamponade. Fluid around the heart, occasionally with tamponade, was seen in about 3% of patients not on dialysis, especially with poor kidney function. Patients are watched closely and an echocardiogram is done if suspected.
Guanethidine. In people already taking guanethidine, minoxidil can cause profound drops in blood pressure on standing; guanethidine is stopped well before if possible, otherwise minoxidil is started in hospital.
Lowering blood pressure too fast. In very severe high blood pressure, lowering it too fast can bring on fainting, stroke, heart attack and loss of vision or hearing. Malignant hypertension is first treated with minoxidil in hospital.
Hair growth is not an approved use. Using minoxidil tablets in any formulation to promote hair growth is not an approved indication. Homemade topical formulations made from minoxidil are considered to share the full range of contraindications, warnings, precautions and adverse reactions on this label.
Kidney failure, recent heart attack, breastfeeding. People with kidney failure or on dialysis may need smaller doses. Minoxidil has not been used within a month after a heart attack. It should not be given to a nursing woman. Hair growth in newborns has been reported after exposure during pregnancy.
From the Patient Information that comes with Minoxidil Tablets:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.