Form N-VP/A GUARDIAN SEPARATE ACCOUN

PROSPECTUS SUPPLEMENT

DATED OCTOBER 8, 2025

FOR

THE GUARDIAN INCOME ACCESS VARIABLE ANNUITY

AND

THE GUARDIAN INVESTOR ASSET BUILDER VARIABLE ANNUITY

Issued by

THE GUARDIAN INSURANCE & ANNUITY COMPANY, INC.

The following supplemental information should be read in conjunction with the Prospectuses and Statements of Additional Information dated May 1, 2018, for The Guardian Investor Income Access Variable Annuity, a variable annuity contract issued through The Guardian Separate Account Q and The Guardian Investor Asset Builder, a variable annuity contract issued through The Guardian Separate Account R.

The information below is added to APPENDIX B: INVESTMENT OPTION RESTRICTIONS, FUNDS AVAILABLE UNDER THE GLWB RIDER in your prospectus, as amended.

Effective November 17, 2025, the following models are available to you for investment:

As always, the availability of any investment option or model is subject to change. See your prospectus for more information concerning the addition, deletion or substitution of investments.

You may make changes to your investment allocations by submitting your written, electronic or telephone instructions in Good Order by mail to Talcott Resolution — Annuity Service Operations, Administrator for your Guardian Annuity Contract, P.O. Box 14293, Lexington, KY 40512-4293 (regular mail) or Talcott Resolution — Annuity Service Operations, Administrator for your Guardian Annuity Contract, 6716 Grade Ln., Building 9, Suite 910, Louisville, KY 40213 (overnight mail), or by calling 1-800-830-4147.

Except as set forth herein, all other provisions of the prospectuses noted above, as previously supplemented, shall remain unchanged.

This Prospectus Supplement must be preceded or accompanied by the most recent

Prospectus available and should be retained with the Prospectus for future reference.