The Locker
A free place to keep the supplements you take, with the dated label for each covered product. When you buy again, you can see whether the formula moved.
Build your LockerAbout
FormulaSignal is an independent supplement record that keeps a dated history of what U.S. supplement labels declare, and tells people when a product they use changes.
Sodium 95 mg to not declared
Labels dated Aug 2026 and Nov 2026
Theacrine 40% Material 50 mg to 125 mg
Labels dated Jan 2026 and Nov 2026
2 of the 33 on file, newest first. See them all, each with both dated labels linked.
A free place to keep the supplements you take, with the dated label for each covered product. When you buy again, you can see whether the formula moved.
Build your LockerScheduled checks on up to 10 covered products, with an email when a change is confirmed. Each month ends with a receipt of every valid, partial and failed check.
See plansA public record for every covered product: its current label, price per serving and history, where they are on file. Signals are the confirmed changes, each with both dated sources.
Browse the recordsPlain questions answered from stored records, such as how much caffeine a product declares or whether it changed. Every answer names its dated source.
Ask the RecordA monthly ledger of the U.S. pre-workout category with verified change alerts, for brand teams. The pilot is $149 a month and limited to five companies.
For brandsThe same Record over REST and a remote MCP server, so software and AI agents can cite dated supplement facts. The free tier allows 30 requests a minute.
Developer docsA product page shows what it says today and nothing else. FormulaSignal keeps 3,185 dated product states going back to 2017, and each figure names the source it came from.
A changed web page is only a lead. A confirmed change needs two comparable dated sources and a review, which is why the Record holds 33 confirmed changes rather than a feed of every edit.
Supplement reviews often describe a formula the brand no longer sells. Each FormulaSignal record names the dated label it refers to, so an old formula and a new one never blur together.
Revenue comes from subscriptions, plus Amazon Associates commission on purchases made through product-page links, built the same way for every product. A brand that pays gets no better treatment and no earlier notice, and FormulaSignal accepts no free product for coverage.
A check that could not read a source is never counted as “no change”. The monitoring receipt lists failed and partial checks beside the valid ones.
FormulaSignal is independent and founder-led, and it started in 2026. It is not affiliated with any brand it covers.
It exists because a supplement can keep its name while its formula changes, and a product page only ever shows today’s label. The Record keeps the ones before it.
Every product starts from the brand’s own page, preserved and hashed before it enters the Record. Label images are read twice and compared.
Monitored products are checked every week or sooner, and watched products every day. Monitoring is open today for pre-workouts, creatine products and protein products.
Build a Locker without an account. Sign in with an email link when you want to keep it, then choose which products to monitor, if any.
Email hello@formulasignal.com for anything: billing, access, questions or corrections. Email is the one direct support channel.
Yes. The Locker holds up to 24 products free, with no card. Signal Pro monitoring is optional; plans are on the Pricing page.
No. It records what a brand declares on its label and product page, with the date and the source. A label is not proof of what is in your container.
A changed page is only a lead. A change is confirmed when two comparable dated sources show different declared values and the finding passes review.
No. Paying brands get no better treatment, no earlier notice of a finding and no right to review it first. Product pages link to the product's own Amazon listing where one exists, and FormulaSignal earns from qualifying purchases. Every product is treated the same way, and nothing that ranks or compares can read those links.
No. FormulaSignal says what a product declared and when. It does not say whether a product is safe, effective or right for you.
Coverage is U.S. pre-workouts, electrolyte and hydration products, creatine products, protein products, EAA and BCAA products, multivitamins, greens powders, and fish oil and omega-3 products, plus some adjacent products. Anything else can be requested free, with no promised date.
Email hello@formulasignal.com with the page and the source you are relying on. Corrections are published beside the finding they change.
Saved to your Locker account
Can’t find something you take? Tell us the brand and product.
Requests live in your Locker, so you’ll make an account next. We’ll carry this over.
No promised date. Requests aren’t monitored.
Not affiliated with or endorsed by any brand shown.