Last week I was responding to a comment underneath one of my 'Paint With Me' videos on Instagram (Username: @BeautyInLagos). The exchange is what sparked the inspiration for this post.
The conversation is shown below:

You should NEVER use a Gel Topcoat over regular polish, here's why.

It takes regular polish a whole 24hours to dry completely; through and through. If, like myself, you are a consistent regular polish user, you will agree that all the quick dry products: Seche Vite Fast Dry, Sally Hanse Insta-Dri, etc. do work, your nail polish becomes dry TO TOUCH. BUT, you still have to be cautious for a few hours after, to avoid dents or creasing. So it is dry, but it doesn't completely 'dry-dry' until at least 24hours after.

Now, Gel polish when it has been cured under the UV/LED light, for 30-60secs depending what formulation you use, it's compared to plastic. Literal, PLASTIC, that's what cured Gel Polish is likened to. And once it cures it's completely dry, you can go about your business like normal.

So imagine what you are doing when you apply a Gel topcoat, that dries like plastic instantly, over regular polish that takes at least 24hours to dry completely... You are trapping moisture into your nail bed and moisture is the most conducive environment for fungus.

I find quite a few Nail Techs here in Lagos advice their clients to do this to get the polish to last longer. This is terrible and very unprofessional advice.

The information I'm sharing I learnt from international Nail Technician & Educator, Mary Negron. We worked together for a couple of years running Nail Tech training classes.

Side Bar: We organised quite a number of group and private training sessions [see some: here, here & here]. We plan to bring back these classes very soon and I do see the emails and DMs we receive enquiring about these trainings, we are working on something.

Anyways, I often sat in on these classes, and this was a cautionary lesson she shared with the students. So I'm not sharing information I plucked out of thing air, these are facts. There's a reason why there's a whole protocol around gel polish application, we don't just get to pick and choose how you do certain things.

So my advice, DO NOT use Gel Topcoat over regular polish it's not good for your nails.