X0609 4 2026-06-04 0 0001711279 Krystal Biotech, Inc. KRYS 0001298709 Krishnan Krish S false C/O KRYSTAL BIOTECH, INC. 2100 WHARTON STREET, SUITE 701 PITTSBURGH PA 15203 1 1 1 0 President and CEO 1 Common Stock 2026-06-04 4 S 0 320 300.75 D 1474933 D Common Stock 2026-06-04 4 S 0 640 302.2367 D 1474293 D Common Stock 2026-06-04 4 S 0 176 303.1689 D 1474117 D Common Stock 2026-06-04 4 S 0 544 304.8102 D 1473573 D Common Stock 2026-06-04 4 S 0 589 306.3318 D 1472984 D Common Stock 2026-06-04 4 S 0 11461 307.6776 D 1461523 D Common Stock 2026-06-04 4 S 0 4830 308.4677 D 1456693 D Common Stock 2026-06-04 4 S 0 2784 309.4901 D 1453909 D Common Stock 2026-06-04 4 S 0 2652 310.429 D 1451257 D Common Stock 2026-06-04 4 S 0 964 311.358 D 1450293 D Common Stock 2026-06-04 4 S 0 40 312.23 D 1450253 D Common Stock 90000 I By SMK Trust FBO KSK Common Stock 50000 I By Krishnan Family Trust The Reporting Person may be deemed to beneficially own shares of the Issuer's common stock directly owned by the Reporting Person's spouse, Suma M. Krishnan. Such shares and transactions by the Reporting Person's spouse are not included in this Form 4, as they are being reported separately on a Form 4 filed by his spouse. The Reporting Person disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein. The sales reported were pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 4, 2025. The Rule 10b5-1 trading plan started on December 4, 2025, and will terminate on December 4, 2026, or earlier in accordance with the terms of the Rule 10b5-1 trading plan, including upon completion of the sale of all of the shares of the Company's common stock subject to the Rule 10b5-1 trading plan. The transaction was executed in multiple trades ranging from $302.05 to $303.01. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $303.05 to $303.82. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $304.07 to $304.98. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $306.00 to $306.99. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $307.03 to $308.02. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $308.03 to $309.01. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $309.04 to $310.01. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $310.06 to $311.00. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. The transaction was executed in multiple trades ranging from $311.07 to $311.77. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. Held by SMK Trust FBO KSK, an irrevocable trust established by Mrs. Krishnan for the benefit of Mr. Krishnan who serves as a co-trustee and shares voting and investment power with a 3rd party co-trustee. Held by the Krishnan Family Trust. The Reporting Person and his spouse are each joint beneficial owners of the trust with joint voting and investment control. /s/ Krish S. Krishnan 2026-06-05