"60-day money-back guarantee" is printed on almost every direct-sold supplement in this category, and it is doing a lot of work in the buying decision. It is also one of the least-read pieces of text on any sales page. Here is what is actually inside a typical one.
What the sixty days is counted from
Almost always the purchase date, not the delivery date and not the date you opened the bottle. On a six-bottle order that matters: if you take a fortnight to start, your effective trial is shorter than the number on the badge suggests. Check the wording — a guarantee counted from delivery is meaningfully more generous than one counted from payment.
Empty bottles, and why they ask
The better guarantees explicitly accept empty bottles, which is the tell that the offer is real. A guarantee that requires unopened product is not a trial period at all — it is a returns policy, and it means you cannot find out whether the thing works without voiding your cover.
Most merchants that accept empties ask you to send the bottles back. That is a real cost and a real errand, and it is worth knowing before you order rather than discovering it on day fifty-eight.
Three things guarantees usually do not cover
Return shipping. Frequently yours to pay, even where the refund itself is full. On a heavy multi-bottle order that is not trivial.
The original shipping charge. Many policies refund the product price only. If you paid delivery on a small pack, expect that to stay paid.
Purchases from anywhere else. Resellers, marketplaces, a friend's spare bottle — all outside. The guarantee belongs to the merchant, and it only covers transactions that merchant handled.
How the process normally runs
Email the support address with your order number. They reply with a returns authorisation and an address. You post the bottles, they receive them, and the refund lands on the original payment method — usually within a week or two of receipt, sometimes longer at the card's end.
The part that goes wrong most often is the authorisation step. Sending bottles back without asking first is the commonest way for a legitimate refund to disappear into a warehouse, because there is nothing tying the parcel to your order.
What a good guarantee looks like
Counted from delivery rather than purchase. Empty bottles explicitly accepted. A named support email rather than a form. A stated refund window measured in days rather than "promptly". And the same terms on the checkout page as on the sales page — if those two disagree, the checkout is the one that binds.
Read it before you buy. It takes two minutes, it is the only part of a supplement purchase that is genuinely enforceable, and it is the difference between a trial and a gamble.