Can you write off product samples if you never publish the review?

Generally, yes — you may be able to deduct the cost of a product sample even if you never publish the review, but only if it was purchased for a real business purpose and you can support that purpose with records.

In the U.S., the key question is whether the expense was ordinary and necessary for your business. If you bought the item to test, evaluate, or potentially feature it as part of a legitimate content or review business, the fact that you later chose not to publish the review does not automatically erase the deduction.

A few important caveats:

• Personal use matters. If you end up using the item personally, only the business portion is deductible, and in some cases none of it may be if the personal use dominates.
• Free samples are different. If a brand sends you a product for free, you usually do not deduct a purchase cost because you did not pay for it. Whether it must be reported as income depends on the facts — for example, whether it was given as compensation, as part of a sponsorship, or as an unsolicited promotional sample.
• Document your business purpose. Keep receipts, notes about how the sample was used, and records showing you were operating with a profit motive, not as a hobby.

So the short answer is: often yes for a purchased sample used for business purposes, but not automatically, and not for personal-use items or every free product. A tax professional can tell you how it should be treated in your specific situation.