Worried your iron supplement might be staining your teeth? You’re not imagining it. Some types, especially liquid forms, can leave dark brown or black marks on enamel if they come into direct contact with your teeth.
I’ve worked with many clients who start iron to improve energy or low ferritin, only to notice their teeth looking duller or discoloured a few weeks in.
So, is it inevitable? Can all forms of iron do this? And more importantly, is there a way to prevent it?

Which Iron Supplements Don’t Stain Teeth
Some iron supplements are far more likely to stain teeth than others — and one form avoids the issue entirely.
Nano iron, a suspension of ultra-fine elemental iron particles in water, does not stain teeth. Unlike conventional iron salts, it doesn't bind to enamel, react with saliva, or leave behind any residue. In fact, you can swish it in your mouth for 30 seconds — or longer — and still see no staining whatsoever. That’s not theoretical; I’ve tested this personally and seen the same result in clients again and again.
This makes it an ideal choice for anyone worried about discolouration, especially those using iron long-term or giving it to children.
Other lower-risk options include enteric-coated tablets or capsules designed to dissolve further down in the digestive tract. These are better than liquids but can still occasionally cause staining if the coating is damaged, chewed, or breaks down early.
If staining is a concern, nano iron is in a class of its own — effective, gentle, and completely non-reactive in the mouth.
How to Remove Iron Supplement Stains from Teeth
If your teeth are already stained from iron, you’re not stuck with it , but how you remove the stain depends on its severity.
For mild stains, try these at-home methods:
- Brush with whitening toothpaste containing gentle abrasives like baking soda or silica.
- Make a paste of baking soda and water; brush gently on stained areas for a minute or two, then rinse well.
- Use a diluted hydrogen peroxide rinse (1 part 3% hydrogen peroxide to 2 parts water), but limit this to once or twice a week.
For more stubborn stains, professional dental treatments may be necessary:
- Air polishing, which uses a pressurised stream of powder and water to buff surface stains.
- Ultrasonic cleaning, which breaks up deeper deposits without damaging enamel.
- In-office whitening treatments that use stronger bleaching agents to lift tough discolouration safely.
Avoid harsh DIY solutions like scrubbing with activated charcoal or using undiluted acids. Though tempting, these can damage enamel and increase sensitivity, creating more problems than they solve.
If stains persist, don’t assume they’re permanent. A dental hygienist or dentist can assess the cause and recommend the safest, most effective treatment.
How to Prevent Iron-Related Tooth Staining
Preventing stains is easier than removing them. Here’s what I advise:
- Use a straw when taking liquid iron supplements to limit contact with your front teeth.
- Rinse your mouth or brush your teeth soon after dosing. Even a quick rinse can reduce staining risk.
- Swallow tablets whole. Avoid chewing or holding them in your mouth.
- Avoid taking iron with tea, coffee, or dairy. These can both interfere with absorption and contribute to staining.
- Maintain good overall oral hygiene. Regular brushing and flossing help keep stains at bay.
If you’re switching supplements or just starting iron, these simple habits can protect your smile while supporting your iron levels.
Frequently Asked Questions About Iron and Teeth Staining
Can iron pills make my teeth yellow?
Yes, especially if tablets are chewed or held in the mouth. Iron can leave a yellowish or brownish residue that builds up over time.
Should I brush my teeth after taking iron supplements?
It’s a good idea to brush or at least rinse your mouth shortly after taking iron to reduce staining risk.
Can iron supplements stain baby teeth?
Yes. Liquid iron given to infants or toddlers can cause staining. Use a dropper aimed towards the back of the mouth and wipe the teeth afterward.
Does nano iron stain teeth?
No. Nano iron doesn’t bind to enamel or react with saliva, so it does not cause any staining, even when swished in the mouth.
Are iron stains on teeth permanent?
Usually not. With proper dental cleaning or professional treatment, most stains can be removed. Longstanding stains may take more than one treatment.
Does ferrous sulfate stain teeth?
Ferrous sulfate, especially in liquid form, is a common cause of staining.
Can iron supplements cause tooth decay?
Iron itself doesn’t cause decay. However, poor oral hygiene combined with iron supplements can create an environment that increases risk.