Minoxidil is one of the most popular and safe longstanding hair loss treatments. It is available both as a topical solution and in oral tablet form. Whilst minoxidil is widely available thanks to over the counter brands like Rogaine, unfortunately it is toxic for pets. Even trace amounts can cause poisoning. In this article, we’ll explore how minoxidil can be dangerous for pets and identify which animals it is toxic to. We’ll also review practical tips to keep your pets safe if using minoxidil, what to do if you suspect toxicity and safer alternatives.
What is Minoxidil?
This is a medication that was initially developed to treat high blood pressure but accidentally became a hair loss treatment when doctors noticed hair growth as a side effect. Minoxidil is available over the counter as as a topical treatment (Rogaine®) in strengths of up to 5%. It is also available by prescription as an oral treatment or in higher strengths or compounded topical solutions. Whilst it is incredibly popular and often first line treatment for androgenetic alopecia, minoxidil (especially in topical formulas 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, topical minoxidil in compounded formulas or products like Rogaine is thought to be more likely to cause harm than oral. This is because topical minoxidil is applied directly to the scalp but not all of it is absorbed through the skin. A residual amount of minoxidil can cling on to hands, hair, towels, clothes and bedding. This creates a risk if licked by dogs or cats. In contrast, oral minoxidil is systemically absorbed and metabolised by the liver and kidneys. As such there is little chance of pets coming into indirect contact with it through skin or surfaces. However it remains a risk to curious pets if they directly ingest it.
Minoxidil works by relaxing the smooth muscle in blood vessel walls and widening them which when used in humans can increase oxygen and nutrient delivery to the hair follicles. In pets, this potent blood vessel dilation can cause breathing difficulties, weakness, stomach upset and in severe cases collapse. The main ways minoxidil causes toxicity in animals include:
- Low Blood Pressure & Rapid Heartbeat: Minoxidil widens blood vessels which lowers blood pressure. In turn this makes the heart beat faster to compensate.
- Fluid in the Lungs: Leaky vessels allow fluid to build up in the lungs. This leads to coughing, trouble breathing and low oxygen levels.
- Stomach Upset: Irritation of the digestive tract can cause vomiting, excessive drooling and a loss of appetite.
- Kidney & Temperature Issues: Reduced blood flow to the kidneys can lead to toxin buildup. Poor circulation may also cause your pet to feel unusually cold.
- Irregular Heart Rhythms: In cats (especially those with pre-existing heart disease), minoxidil can trigger dangerous life-threatening arrhythmias.
Which Animals are at Risk of Minoxidil Toxicity?
Minoxidil toxicity can affect a range of mammalian pets but there’s limited published research on this area. Instead we largely rely on small case studies and reports from vets and pet owners. What we do know is that most documented cases of minoxidil being toxic is in animals like cats and dogs normally due to topical treatments like Rogaine. Below are the animals at greatest risk:
- Cats: Highly sensitive to minoxidil. Cats can become seriously ill after just one lick of treated skin, hair or bedding.
Dogs: Whilst their larger size offers some buffer, dogs remain vulnerable even if they only ingest multiple drops, chewed applicators or discarded tissues. - Other Pets: There’s limited information on birds, rabbits or reptiles but you should never assume safety. Treat minoxidil like any other household toxin and keep it well out of reach of any animals.
Signs of Minoxidil Toxicity in Pets
Exposure to minoxidil can lead to a range of symptoms in pets which often appear within the first 1–48 hours. Early recognition of these poisoning is vital to ensure prompt treatment and better outcomes. Here are some of the main signs of minoxidil toxicity in animals that you should look for:
- Lethargy & weakness
- Vomiting, drooling or loss of appetite
- Bounding pulses or rapid heart rate
- Laboured breathing, coughing or open-mouth breathing
- Hypothermia and cyanosis (bluish mucous membranes)
- In severe cases there may be collapse, seizures or sudden death
What to Do If You Suspect Poisoning
If your pet displays any of these symptoms after potential contact with minoxidil, please seek help without delay. This is because treatment may require intravenous fluids, blood pressure monitoring, oxygen therapy and even cardiac support. Here are some top tips if you suspect minoxidil poisoning of your pet:
- Stay Calm & Act Fast: Phone your Vet or an emergency pet poison hotline immediately. In the UK, you can contact the Veterinary Poisons Information Service.
- Follow Expert Advice: Do not induce vomiting or administer home remedies unless explicitly directed by a professional.
- Decontamination: Remove any obvious bottles, materials or objects that might be the source of minoxidil exposure. If instructed, bathe your pet with soap and warm water to remove any residue.
- Ongoing Monitoring: Keep your pet warm, quiet and observe their symptoms until they’ve been given the all clear by the Vet.
Top Tips to Prevent Minoxidil Poisoning
If you wish to use oral or topical minoxidil, you’ll need to take a few precautions to prevent accidental minoxidil poisoning in your pets. To tips to minimise exposure and keep your pets safe include:
- Secure Storage: Keep both topical solutions and oral tablets in a locked cabinet, well out of reach of curious animals.
- Mindful Application: Apply Minoxidil in an area away from the pets and make sure it has dried on your scalp before going near them. Don’t let pets lick your hair or skin near the scalp
- Waste Disposal: Discard of used tissues, cotton buds and empty bottles in a pet-proof bin as soon as you’re done
- Diligent Hand-Washing: Wash for at least 20 seconds after every application and again before handling your pets. Wash off minoxidil from any surfaces if it spills
- Allow Time to Absorb: Wait at least two hours post-application for topical products to absorb or evaporate fully before cuddling your pet
- Protect Your Bedding: Sleep on a dedicated towel or cap, then launder it separately to remove any residue.
- Prevent Contact with contaminated Items: Keep the pets away from any bedding, towels, brushes or anything that normally comes into contact with your hair or minoxidil
Alternative Hair Loss Treatments
Oral (tablet) minoxidil poses far less risk of secondary exposure than topical formulas as very little of the drug ends up on your skin. However, any loose minoxidil tablets can still be toxic if chewed or swallowed by an animal, so you will always need to remain very cautious. If you’d rather avoid minoxidil altogether, here are some alternatives:
- Ketoconazole Shampoo: This can help treat mild cases of male and female pattern hair loss. Rinse thoroughly after using to remove all residue from hair and hands. Ketoconazole is thought to be safe around pets although avoid getting them in contact with it.
- Low-Level Laser Therapy (LLLT): A non-chemical, at-home or in-clinic laser device, LLLT is safe for pets as there is zero risk of ingestion or contact with residue. Just don’t use it on them!
- Platelet-Rich Plasma (PRP): This is an in-office treatment using your own blood’s growth factors to stimulate hair growth.
- Microneedling: This is a procedure that stimulates vascularisation and wound healing to help revive hair follicles. It can be at home or performed in-clinic. Be careful if you’re provided with any serums to use alongside the treatment and ensure that they don’t contain pet toxic ingredients.
Topical (e.g. Rogaine) and oral minoxidil are effective for treating hair loss but they can be toxic to pets (especially cats and dogs). You can reduce the risk of minoxidil poisoning to your pets by recognising which animals its toxic to and spotting early warning signs. With a few precautions and application tips, you can safely use minoxidil and prevent your pet from coming in contact with it.
We employ a bespoke approach to hair care which is why we offer personalised hair loss and regrowth treatments through our online skin clinic. Our doctors create custom hair growth treatments using actives such as Minoxidil, Spironolactone, Melatonin, Caffeine and Tretinoin where appropriate for each and every patient. Start your virtual consultation and begin your journey to great hair today.
