I’ve already talked about using sunscreen containing zinc oxide as diaper cream. But what about the other way? Can you use diaper cream as sunscreen, provided it contains zinc oxide (NOT petroleum jelly!) as an active ingredient?
In theory, YES.
But you should only do this if you’re in a pickle and not make it a habit.
1. Zinc oxide comes in different varieties.
This goes beyond the nanoparticle aspect of zinc oxide that sometimes becomes the point of a great debate (nano vs. non-nano zinc oxide) though it does come into play here.
The particle size of zinc oxide seems to matter in terms of sun protection. In fact, sunscreen manufacturers work hard trying to strike a balance between the ups and downs of both nano- and non-nano zinc oxide (at least from what we know about the properties of nanoparticles so far).
This means that some zinc oxide formulations may be better at sun protection than others. But – purely theoretically – this can apply to both sunscreens and diaper creams.
I also found that some sunscreen grade of zinc oxide can be coated with various inert substances to reduce its presumed photo reactivity and to make it easier to mix with other ingredients. Many sunscreens are intentionally made with uncoated zinc oxide though, so I don’t see this as being an issue.
2. The percentage of zinc oxide matters.
The higher the percentage of zinc oxide, the better the protection from harmful sun rays.
Simply put, a diaper cream may not contain enough zinc oxide to provide sufficient protection from UV rays.
For example: BADGER uses identical USP grade zinc oxide for their diaper cream and kids’ sunscreen, but the percentage is different in both products. (10% zinc oxide in Badger diaper cream vs.18.75% zinc oxide in Badger kids’ sunscreen.)
3. Ingredients may react.
Mineral sunscreen efficacy is based on more than just the type or the amount of zinc oxide used. The way each product is formulated can change the pH which can affect the properties of zinc oxide.
In other words, other ingredients contained in the zinc oxide formula can affect how much UV radiation is filtered.
4. Sunscreens are DESIGNED to scatter UV rays – diaper creams are not.
Sunscreens are designed to provide protection from UV rays, and they’re also tested to indeed do what they claim to do.
A diaper cream may provide sufficient protection from UV rays, but it may not. It’s anyone’s bet.
You simply don’t know the level of SPF you’re getting in a zinc oxide-based diaper cream.
If diaper cream contains the right concentration of zinc oxide and no ingredients are present in the final formula that could compromise UV protection, it will work as sunscreen as well.
If you have nothing else to use under the blazing sun, using diaper cream as sunscreen is theoretically better than using nothing at all. (As long as it contains zinc oxide as the main ingredient!)
But, remember to only use diaper cream as sunscreen when left in a pinch!
Oh, and before I forget – check for fish oil / cod liver oil in the ingredient list – that could be an unpleasant aftermath of using diaper cream as sunscreen…