“I don’t know! Why do razor blades have lubricating strips at the top?”
Sounds like a riddle.
It is one of those things I take for granted. Similar to:
Why does a glass of Guiness always come with a tall frothy head on it? Just leaves a stain on your upper lip hair.
Or why does the barista play with the top of my coffee to leave a pattern? Pointless after the first sip.
And the topic, it is a great question as I have generally ignored the lubricating strip on a razor blade insert as being necessary.
Warning - personal hygiene content follows. You might experience unexpected feelings of awe and amazement, or be bored to sleep.
More scientifically. I’d suggest it is pointless based on my routine. And that the amount of magic lubricant contained in the microscopic strip really can’t be sufficient to coat the average face every day for a week or realistically a month! Yes that’s right! I get about a month out of a blade shaving a full face most days of the week.
At one point in time I actually looked for inserts without the strips as those with strips seemed to agrivate my skin!
Today I simply use a water soluable gel based lubricant to reduce razor friction. No irritation. If the QA fails there is always enough residual slime on the spare hand to lightly recoat that part of the chin for a second glide!
When travelling I often pack a cheap environmentally challenging disposable razor. Typically one with no lubricating strip. And use the same gel based shaving product. The non strip razors glide equally well without the strips.
Although with disposables the quality of the blades seems to vary with brand. Typically the blades don’t hold their edge for as long, less than a week.
Perhaps the strip on a razor insert (cartridge) does do as advertised. Experience suggests any benefit to the user is doubtful.
Perhaps a dry shave test is called for. Count me out!