Home | The Longevity Letter

There is no such thing as sunblock

There is no such thing as sunblock

SPF tells you how long it takes to burn. It does not tell you how well you're protected from aging, pigment, or the light your sunscreen ignores.

Hillary Lin, MD

•

Jul 6, 2026

Peptides get the hype. These amino acids get the results.

Peptides get the hype. These amino acids get the results.

The leucine paradox, the $20 GlyNAC stack, and why your protein shake math changes at 50.

Apr 8, 2026

•

24 min read

Your Biological Age Test Might Be Lying to You

Your Biological Age Test Might Be Lying to You

Mar 23, 2026

•

30 min read

Subscribe to The Longevity Letter

Join the list to receive our newest posts straight to your inbox.

Latest

There is no such thing as sunblock

There is no such thing as sunblock

The Peptide Gray Zone

The Peptide Gray Zone

Is the next longevity "wearable" a full-body scan?

Is the next longevity "wearable" a full-body scan?

How to lose the right kind of weight

How to lose the right kind of weight

The Longevity Spring Clean

The Longevity Spring Clean

Do not fear the broccoli

Do not fear the broccoli

Your blood pressure is not boring. Your annual physical just makes it look that way.

Your blood pressure is not boring. Your annual physical just makes it look that way.

The most important aging clock is not your biological age

The most important aging clock is not your biological age