Minoxidil is one of the most popular and well-established hair loss treatments. It comes as both a topical liquid and an oral tablet. Whilst it is widely available thanks to over-the-counter brands like Rogaine, it is unfortunately toxic to pets. Even trace amounts can cause poisoning. In this article we explore how minoxidil can be dangerous for pets and which animals it affects. We also review practical tips to keep your pets safe if you use it. On top of that, we cover what to do if you suspect toxicity, and safer alternatives.
What is Minoxidil?
This is a medicine that was first developed to treat high blood pressure. In fact, minoxidil became a hair loss treatment by accident, when doctors noticed hair growth as a side effect. It is available over the counter as a topical treatment (Rogaine) in strengths of up to 5%. You can also get it on prescription as an oral treatment, or in higher strengths and custom topical liquids. It is hugely popular and often the first-line treatment for androgenetic alopecia. However, minoxidil (especially in topical forms like Rogaine) can be toxic to animals and pets.
How Minoxidil Causes Toxicity in Pets
Whilst all forms of minoxidil can be toxic to pets, the topical version is thought to be the riskier one. That is true of custom forms and products like Rogaine. This is because you apply the topical version to the scalp, and not all of it soaks into the skin. A residual amount can cling to hands, hair, towels, clothes and bedding. This is a risk if a dog or cat licks it. The oral form, by contrast, is absorbed into the body and broken down by the liver and kidneys. So there is little chance of pets meeting it on skin or surfaces. It does, however, remain a risk to a curious pet that swallows a tablet directly.
Minoxidil works by relaxing and widening the smooth muscle in blood vessel walls. In people, this increases the oxygen and nutrients delivered to the hair roots. In pets, this strong widening of the blood vessels can cause breathing trouble, weakness, stomach upset and, in severe cases, collapse. The main ways it causes toxicity in animals include:
- Low blood pressure and rapid heartbeat: minoxidil widens the blood vessels, which lowers blood pressure. In turn, this makes the heart beat faster to compensate.
- Fluid in the lungs: leaky vessels let fluid build up in the lungs. This leads to coughing, trouble breathing and low oxygen levels.
- Stomach upset: irritation of the gut can cause vomiting, heavy drooling and a loss of appetite.
- Kidney and temperature issues: reduced blood flow to the kidneys can let toxins build up. Poor circulation may also make your pet feel unusually cold.
- Irregular heart rhythms: in cats, especially those with existing heart disease, minoxidil can trigger dangerous, life-threatening arrhythmias.
Which Animals are at Risk of Minoxidil Toxicity?
Minoxidil toxicity can affect many kinds of pet, but there is limited published research here. Instead we largely rely on small case studies and reports from vets and owners. What we do know is that most documented cases involve cats and dogs, usually from topical products like Rogaine. The animals at greatest risk are:
- Cats: highly sensitive to minoxidil. A cat can become seriously ill after just one lick of treated skin, hair or bedding.
- Dogs: their larger size offers some buffer, but they are still vulnerable, even from a few drops, chewed applicators or discarded tissues.
- Other pets: there is little information on birds, rabbits or reptiles, but you should never assume they are safe. Treat minoxidil like any other household toxin and keep it well out of reach of any animal.
Signs of Minoxidil Toxicity in Pets
Exposure to minoxidil can cause a range of symptoms in pets, which often appear within the first 1 to 48 hours. Spotting the signs early is vital for prompt treatment and a better outcome. The main signs to look out for include:
- Lethargy and weakness
- Vomiting, drooling or loss of appetite
- A bounding pulse or rapid heart rate
- Laboured breathing, coughing or open-mouth breathing
- A low body temperature and cyanosis (a bluish tinge to the gums)
- In severe cases, collapse, seizures or sudden death
What to Do If You Suspect Poisoning
If your pet shows any of these symptoms after possible contact with it, seek help without delay. Treatment may involve intravenous fluids, blood pressure monitoring, oxygen therapy and even support for the heart. Here is what to do if you suspect poisoning:
- Stay calm and act fast: phone your vet or an emergency pet poison line immediately. In the UK you can also contact the Veterinary Poisons Information Service.
- Follow expert advice: do not try to make your pet vomit or give any home remedies unless a professional tells you to.
- Remove the source: take away any bottles, materials or objects that might be behind the exposure. If you are told to, bathe your pet with soap and warm water to wash off any residue.
- Keep watching: keep your pet warm and quiet, and watch their symptoms until the vet gives the all-clear.
Top Tips to Prevent Minoxidil Poisoning
If you want to use oral or topical minoxidil, a few precautions will help prevent accidental poisoning in your pets. Tips to lower exposure and keep your pets safe include:
- Secure storage: keep both topical liquids and oral tablets in a locked cabinet, well out of reach of curious animals.
- Mindful use: apply it away from your pets and make sure it has dried on your scalp before you go near them. Do not let pets lick your hair or skin near the scalp.
- Waste disposal: put used tissues, cotton buds and empty bottles in a pet-proof bin as soon as you are done.
- Diligent hand-washing: wash for at least 20 seconds after every use, and again before you handle your pets. Wash any spills off surfaces too.
- Allow time to absorb: wait at least 2 hours after applying for topical products to absorb or dry fully before you cuddle your pet.
- Protect your bedding: sleep on a dedicated towel or cap, then wash it separately to remove any residue.
- Prevent contact with contaminated items: keep pets away from any bedding, towels, brushes or anything that usually touches your hair or minoxidil.
Alternative Hair Loss Treatments
Oral (tablet) minoxidil poses far less risk of secondary exposure than topical forms. Very little of the drug ends up on your skin. Even so, a loose tablet can still be toxic if an animal chews or swallows it. So you will always need to stay careful. If you would rather avoid minoxidil altogether, here are some alternatives:
- Ketoconazole shampoo: this can help with mild male and female pattern hair loss. Rinse thoroughly after use to clear all residue from your hair and hands. Ketoconazole is thought to be safe around pets, though you should still keep them away from it.
- Low-level laser therapy (LLLT): LLLT is an at-home or in-clinic device that uses no chemicals. It is safe around pets, as there is no residue to lick or touch. Just do not use it on them.
- Platelet-rich plasma (PRP): this in-clinic treatment uses growth factors from your own blood to stimulate hair growth.
- Microneedling: this procedure boosts blood supply and wound healing to help revive hair roots. It can be done at home or in clinic. Take care if you are given any serums to use alongside it. Check that they do not contain ingredients that are toxic to pets.
Topical (such as Rogaine) and oral minoxidil are both effective for hair loss. However, they can be toxic to pets, especially cats and dogs. You can lower the risk of poisoning by knowing which animals it affects and spotting the early warning signs. With a few precautions and sensible habits, you can use it safely and keep your pet well away from it.
We employ a bespoke approach to hair care, which is why we offer personalised hair loss and regrowth treatments through our online clinic. Our doctors create custom hair growth treatments for each patient. Where appropriate, these use actives such as minoxidil, spironolactone, melatonin, caffeine and tretinoin. To start, book a virtual video consultation or use our online consultation form. The journey towards great skin and hair starts here.
This article is intended for general informational purposes only and is not a substitute for medical or veterinary advice, diagnosis or treatment. Always consult a qualified medical professional with any concerns about your hair or treatment options, and a vet with any concerns about your pet.
