Potential risks of oral Minoxidil – what your doctor may not know

Oral Minoxidil is currently a commonly prescribed treatment for hair loss in women and men. It’s use for this purpose is ‘cosmetic’ and ‘off label’ – meaning minoxidil is not approved for hair loss (1) but may be prescribed at a medical doctor’s discretion after side effects, risk factors, and alternate treatments have been explained to the patient.

Oral minoxidil has even been seen to be offered online without a doctor’s consult required and therefore presumably without a prescription or evaluation of the customer’s suitability to take this drug.

But is oral minoxidil as benign a drug as its cavalier prescribing would imply?

2020 research cites minoxidil as a mitogenic agent even when applied topically. Mitogens are believed to have carcinogenic and mutagenic potential by inducing cell division and increasing the possibility of causing ongoing DNA damage.

In laboratory trials using hairless mice, the topical ‘all over’ application of minoxidil produced defects in the DNA of the rodent’s red blood cells. This DNA damage is believed to potentially compromise the life of the test mouse as well as its offspring due to genetic material (DNA) destruction (2).

With its systemic actions oral minoxidil has a greater side effect profile than topically applied minoxidil, so the potential for greater harm is self-evident.

Other possible side effects of Minoxidil include tachycardia (rapid heartbeat) and palpitations, hypertrichosis (increased, excessive body hair), chest tightness and chest pain, difficulty in breathing when lying down, weight gain, bloating, headaches, swelling of the face, hands, feet and lower legs.

Though generally unreported to the appropriate regulators, Minoxidil adverse reactions requiring hospital admission are not uncommon. This writer is aware of at least three cases; two younger adults suffered a respiratory arrest whilst a 60yo woman needed ICU care for cardiac anomalies after being prescribed an excessive dose of oral Minoxidil.

In 2022 the US Food and Drug Administration (FDA) issued a ‘boxed’ (aka: black box) (3) warning for life-threatening cardiac events (4) and ECG changes in patients prescribed low-dose oral minoxidil (LDOM).

Salient point:  ALL medication taken orally will generally have a ‘systemic’ effect on body physiology for what the drug has been intended to treat, ie: blood pressure or cholesterol. Oral minoxidil would therefore not be specific to enhancing scalp hair growth, but every part of the body that possesses hair follicles (5).

Women particularly are just as likely to exhibit increased pubic, facial or generalised body hair as any increase in scalp follicle hair growth.

Spironolactone is another blood pressure drug prescribed ‘off label’ for female hair loss. Spironolactone and minoxidil are often prescribed together and even combined in the same capsule. People with pre-existing heart problems and hypertension should not take these drugs. Minoxidil is known to increase the severity of angina (6).

Before accepting either of these drugs – neither of which are officially approved as treatments for hair loss and come with significant potential side effects, appreciate that hair loss in women is almost always an indicator of underlying disturbance, deficiency, or an imbalance of hormonal status at your current stage of life.

The state our hair is not something separate from the body, but a reflection of changes within our body. Neither drug will have any positive influence on these underlying disturbances – at best they are temporary and (often) ineffective band-aids for your hair loss concerns.

Copyright: Anthony Pearce 2023 (Revised December 2024).

1. Minoxidil was originally approved for severe hypertension (high blood pressure) where other anti-hypertensives proved inadequate.
2. National Institutes of Health (.gov) https://www..ncbi.nlm.nih.gov PMC 7222831. Note: these findings may be tissue or species-specific and trials have not been evaluated in humans. Researchers did advise excessive exposure to minoxidil should be avoided.
3. Black box warnings are the strictest classification requirements that the FDA can mandate for prescription drugs. First implemented in 1979, black box warnings highlight serious and sometimes life-threatening adverse drug reactions within the labelling of prescription drug products.
4. Pericardial effusion and cardiac tamponade.
5. Only the palms of hands and soles of feet are devoid of hair follicles on the normal human body.
6. Acute chest pain due to decreased heart muscle blood supply.