The meanings are exactly the same.
The only very small difference, is that sometimes it is more common to use a pronoun or a noun with 'from'. For example:
'Sunscreen protects YOUR SKIN from the sun's harmful rays' - Here the noun 'your skin' means that we are more likely to use 'from', but it doesn't really matter, you can still use against.
'Sunscreen protects against the sun's harmful rays' - Here the fact that there is no noun means that we are more likely to use 'against', but it doesn't really matter, you can still use from.
'I will protect YOU from him'
'These gloves protect MY HANDS from the cold.'
'This new product protects against baldness'
'This cream protects against bacteria.'
Again, in all of those examples you can still use the other preposition, it is just that with a noun or pronoun from is sometimes more common.
Like I said, 'from' and 'against' really are interchangeable, it has no effect on the meaning.