Comments on: How SPF Changes With How Much Sunscreen You Use

By: Nicol Hawkins

Nicol Hawkins — Sun, 13 Dec 2020 15:23:40 +0000

In reply to Michelle. Okay thank you!

By: Michelle

Michelle — Sun, 13 Dec 2020 07:44:10 +0000

In reply to Nicol Hawkins. Unfortunately reapplication isn't about quantity, but time - the sunscreen film breaks up as time goes on, so it stops giving as good protection as it should.

By: Nicol Hawkins

Nicol Hawkins — Fri, 11 Dec 2020 17:23:33 +0000

Hi Michelle! I have a question about reapplication. Most days I am indoors, except to walk my dog twice a day or driving to the store. I was wondering if using a full 1/4 tsp for my face and neck would provide me an even layer of protection for the day so I won’t need to reapply. My apartment does get very sunny in the afternoon with lots of direct and indirect light. I’m also using Elta MD’s Physical Tinted SPF 41.

By: Michelle

Michelle — Thu, 19 Nov 2020 03:50:15 +0000

In reply to paris.

There are some here: https://labmuffin.com/my-sunscreen-mini-review-spreadsheet/ and here: https://labmuffin.com/video-my-top-6-favourite-sunscreens/

By: paris

paris — Thu, 12 Nov 2020 05:02:42 +0000

Hello!

Great blog you have going on 🙂 Very informative!
I was wondering do you have a page where you talk about sunscreens that you do like?

By: Rach

Rach — Tue, 27 Oct 2020 18:07:35 +0000

Hey Michelle- i love your work. Thanks for this incredibly informative blog post :) i have a related question that i was hoping you could help me with: did I understand correctly that it’s the consensus that in vivo trials proved that the relationship between the thickness of sunscreen application and the spf/ppd is linear? And that the previous in vitro trials had (erroneously) assumed they would be exponential? I ask because from what I’m seeing online it looks like theres no consensus, ie that some in vivo studies show that in higher spfs its actually exponential. But im really hoping that im just missing something/didn’t understand correctly. Thanks again for all your hard work! Will hope to hear your thoughts on this :)

By: Michelle

Michelle — Mon, 04 Jun 2018 12:00:56 +0000

In reply to Lina. It's impossible to say unfortunately - there are so many factors that go into determining the SPF!

By: Lina

Lina — Wed, 30 May 2018 06:52:03 +0000

Dear Michelle, I appreciate your knowledge and the information you provide. I have a hypothetical question: assuming you use a sufficient amount of sunsceen A (SPF 50 sunscreen) – let it fully dry on your skin and layer a (also sufficient) amount of sunscreen B (30 SPF sunsceen) on top of the 50 SPF sunscreen. Assuming the filters of the both sunscreens are not going to degrade each other, which resulting SPF will you achieve and why? Thank you very much for your answer in advance. Greetings from Germany, Lina

By: Petronel

Petronel — Fri, 22 Sep 2017 17:38:34 +0000

People remember this. Sun is also good for your skin, in moderation of course.

By: Anne

Anne — Mon, 07 Nov 2016 18:29:21 +0000

Brilliant article and blog!

-Pharmacist, Vancouver, Canada