Fatigue is the complaint I see most often and the one most reliably solved by the cheapest possible intervention.
Run the cheap test first
There is a diagnostic logic to this that most people skip.
Dehydration resolves in days. B12 and iron take weeks and need a blood test to justify. Under-eating needs a dose conversation, not a purchase.
So start with the fastest and cheapest thing that could explain it. One electrolyte serving a day for a week costs almost nothing and tells you a great deal, whichever way it goes.
Ranked · supplements for GLP-1 fatigue
How this was ordered: Ordered by how frequently each underlying cause actually explains GLP-1 fatigue, and how quickly correcting it produces a noticeable change. Cheap interventions that resolve within days rank above expensive ones that take months.
| # | Product | Key spec | Price | Best for |
|---|---|---|---|---|
| 1 | GLP-1 FoundationMinome | 1,000 mg sodium · 200 mg potassium · 60 mg magnesium + 5 g creatine | $39.99/mo sub | The most common cause, corrected fastest |
| 2 | Vitamin B12Generic / Nature Made | 500–1,000 mcg daily | ~$8–12 for months | Metformin users and anyone eating very little |
| 3 | Iron (with a ferritin result)Generic | As directed after testing | ~$10–15/mo | Menstruating women with low ferritin |
| 4 | Gold Standard 100% WheyOptimum Nutrition | 24 g protein per scoop | ~$1.10/serving (~$33/mo) | Fatigue from simply not eating enough |
| 5 | Basic Nutrients 2/DayThorne | Comprehensive multivitamin · NSF Certified for Sport | ~$36/mo | Broad cover when you will not test |
1. GLP-1 Foundation
Dehydration and sodium depletion explain more GLP-1 fatigue than every other cause combined, and they are the only ones that resolve within days rather than months. A serious electrolyte load is the fastest diagnostic test you can run on yourself: correct it, and if the tiredness lifts inside a week you had your answer cheaply.
Against it The sodium load is a clinical question if you have hypertension or heart failure. And if fatigue is not fluid-related, this will do nothing for it — which is useful information, but not what you paid for.
2. Vitamin B12
B12 deficiency causes exactly this kind of fatigue, absorption falls with age, and long-term metformin — extremely common in this population — depletes it further. Cheap, safe and genuinely corrective when it is the cause.
Against it Does nothing whatsoever if your B12 is normal, which it often is. This is a supplement to take after a result, not instead of one.
3. Iron (with a ferritin result)
Iron deficiency is a leading cause of fatigue in menstruating women, and reduced food intake makes it more likely. When it is the cause, correcting it changes things substantially.
Against it Do not take iron speculatively. It worsens constipation, which you probably already have, and iron overload is a real harm. This entry requires a ferritin test before it means anything.
4. Gold Standard 100% Whey
Some GLP-1 fatigue is straightforward under-eating. If your intake has fallen below roughly 1,200 calories, no micronutrient fixes that, and protein is the macronutrient most likely to be short.
Against it Treats a symptom of a bigger problem. If you genuinely cannot eat enough, that is a dose conversation with your prescriber, not a shopping decision.
5. Basic Nutrients 2/Day
If you are not going to get bloods done, a comprehensive multivitamin is the least unreasonable way to cover several possible gaps at once.
Against it A scattergun where a test would give you a rifle. Ranked last because guessing costs more than testing and takes longer to work.
Prices checked September 2026 and change often. No link on this page is an affiliate link, and no brand listed has paid for, reviewed, or been shown this ranking before publication.
When to stop shopping and start testing
If a week of proper fluid, sodium and sleep has not shifted it, the answer is not on a supplement shelf.
Ferritin, B12, thyroid function and a basic metabolic panel are all reasonable asks, and “my food intake has dropped by half since starting this medication” is a perfectly good reason for a clinician to order them.
Fatigue is the symptom this market most likes to sell into, because it is vague enough that anything can claim to have helped. Test, then buy.
What the timing tells you
The pattern matters as much as the symptom, and it is free to observe.
Fatigue that peaks in the two days after your injection and lifts by the weekend is drug-related and usually improves as you adapt to the dose. Fatigue that is flat across the whole week, regardless of where you are in the cycle, is more likely nutritional or haematological — and that is the version that warrants bloods rather than patience.
Fatigue that appeared only after a dose increase often resolves by staying at that dose an extra few weeks instead of stepping up again on schedule.