Krystal Biotech, Inc.

Insider Trading Arrangements

On September 4, 2025, Krish Krishnan, our Chief Executive Officer and Chairman of our Board of Directors, adopted a Rule 10b5-1 trading arrangement (the “Trading Plan”) that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act for the sale of up to 100,000 shares of our Common Stock, subject to certain conditions. The end date of the Trading Plan is December 4, 2026, subject to early termination in accordance with the terms of the Trading Plan, including upon completion of the sale of all of the shares of our Common Stock subject to the Trading Plan.

On September 4, 2025, Suma Krishnan, our President and a member of our Board of Directors, adopted a Rule 10b5-1 trading arrangement (the “Trading Arrangement”) that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act for the sale of up to 100,000 shares of our Common Stock, subject to certain conditions. The end date of the Trading Arrangement is December 4, 2026, subject to early termination in accordance with the terms of the Trading Arrangement, including upon completion of the sale of all of the shares of our Common Stock subject to the Trading Arrangement.

During the three months ended September 30, 2025, no other director or officer (as that term is defined by the SEC in Rule 16a-1(f) under the Exchange Act)adopted orterminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.