Generally, Google says you should never let Google index your internal search result pages. But John Mueller of Google said you shouldn't even be considering going against Google's advice here, if you have good category pages, you won't even need to test this out.
John said on Twitter "If you have good category pages, there's usually no need to also have search pages indexed." That means, (1) people won't have to search your site to find what they are looking for, they can just use your navigation and (2) Google will index your category pages and rank them, if you want Google to rank a search results page, then maybe that should be a category page...
John also added that having your internal search results pages can lead to spam or other issues. John said "Also, it's possible to accidentally end up with "buy cheap pharmaceuticals at 1-800-PILLS4YOU" search pages indexed, if you don't take care of them ahead of time."
Here are those tweets:
If you have good category pages, there's usually no need to also have search pages indexed. Also, it's possible to accidentlly end up with "buy cheap pharmaceuticals at 1-800-PILLS4YOU" search pages indexed, if you don't take care of them ahead of time.
— John Mueller is mostly not here 🐀 (@JohnMu) November 8, 2022
Forum discussion at Twitter.
