GLP-1
Hair loss on a GLP-1: what the evidence actually shows, and how to protect your hair
A dermatologist on why GLP-1 shedding starts at month three, what the studies actually found, and what to start before it begins.
Journal
Journal
Longer pieces on the questions patients ask me most, written so you can act on them. Evidence first, and always what I would tell you in the office.
GLP-1
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beauty
How to choose a vitamin C serum for your skin type
Beauty How to choose a vitamin C serum for your skin type By Rebecca Marcus, MD · September 2026 · 9 min read Some links in th...
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pigment
Why tinted sunscreen works better for melasma
A dermatologist on why iron oxides in tinted sunscreen protect against the visible light that drives melasma, and how to choose one.
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pigment
Tranexamic acid: the pigment ingredient that treats both brown and red
A dermatologist on why tranexamic acid works on both post-acne brown marks and redness, the 2–5% that matters, and why formulation decides it.
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skin-barrier
Why moisturizer matters more than you think
I ran out of my moisturizer while traveling this summer and bought whatever was on the shelf near the hotel, and by day three my skin had gone flat...
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retinoids
Starting a retinoid without wrecking your skin
If you only ever add one active to your routine, this is the one I would choose, because retinoids have more evidence behind them than anything els...
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hair-loss
Why your hair is shedding and what actually helps
Hair loss is one of the hardest things to talk about and one of the most treatable, which is a difficult combination, because most people wait year...
pigment
Melasma: why it keeps coming back, and what you can do about it
Melasma is one of the most common reasons patients come to see me, and it can be frustrating to live with, because it responds to treatment and the...