Cost per serving: how to shop supplements and protein by the numbers
The front of a package is designed to sell. The numbers that matter are on the back: how much you actually get, and what that costs per unit. Here's the one formula we use for both magnesium and protein, with real prices from our two guides.
Disclosure (Anzeige). Buttons to the Magnesium Decoder, the GLP-1 protein toolkit and the $9 bundle go to guides Renvo Life sells on Payhip. We earn from those sales. Each one is marked Anzeige / Werbung (paid link), the same label as our other paid links. No food or supplement brand paid to be mentioned. How we make money.
Not medical advice. This is a shopping and label guide. Your clinician sets your protein target. Don't change your medicine because of anything here.
The one formula
Cost per unit = price ÷ (servings × amount per serving) × unit size. For magnesium, the unit is 100 mg of actual (elemental) magnesium. For protein, it's 20 g of protein. It's the fairest way to compare a 60-capsule bottle with a 1 kg bag, or a dozen eggs with a tub of yogurt.
Magnesium: cost per 100 mg
In the Magnesium Decoder's table of 30 products, the same 100 mg of magnesium cost from about $0.03 to $1.16 (brand store prices, checked 21 Oct 2026). Budget citrate and glycinate capsules with complete labels came in at about 8 to 18 cents. Premium brands cost 2 to 4 times that, and threonate 6 to 9 times. The full breakdown is in magnesium cost per dose compared. How to read the "Magnesium" line is in label math.
Protein: cost per 20 g
| Food | $ per 20 g protein | Portion for 20 g | Texture |
|---|---|---|---|
| Lentils, dry | $0.45 | 81 g (dry weight) | Needs chewing |
| Chicken eggs, large | $0.60 | 159 g | Soft |
| Mackerel, canned | $0.71 | 80 g | Needs chewing |
| Greek yogurt, plain nonfat | $1.50 | 210 g | Soft |
| Cottage cheese | $2.08 | 161 g | Soft |
| Protein shake, ready-to-drink | $3.48 | 217 g | Drinkable |
From the GLP-1 protein toolkit's ranking of 40 US protein foods: BLS September 2026 US city averages and dated US store receipts. Your store will differ. The toolkit page explains which rows were priced that way and which say "price not verified".
The same idea applies to shakes and bars. The toolkit compares 13 products, ranging from $0.63 to $6.60 per 20 g of protein. Portion size matters too if your appetite is small: 20 g of protein is about 210 g of Greek yogurt but only about 160 g of eggs. Those figures are shopping math, not a target. Your clinician sets the target.
Both guides, one download: $9
The Magnesium Decoder ($7) and Protein on a Small Appetite, the GLP-1 protein toolkit ($7), together for $9 instead of $14. You get two PDFs, two spreadsheets and printables. Read what each one covers on its own page first: Magnesium Decoder and GLP-1 protein toolkit.
Get the bundle for $9 on Payhip Anzeige / Werbung (paid link)
Or buy one guide: Magnesium Decoder, $7 Anzeige / Werbung (paid link) GLP-1 protein toolkit, $7 Anzeige / Werbung (paid link)
Free samples, no email: Magnesium Decoder (4 pages) · GLP-1 protein toolkit (5 pages).
Magnesium forms on one page
How much of each form is actual magnesium (oxide ≈60%, citrate ≈16%, glycinate ≈14%, threonate ≈7–8%) and what the research says, in plain words. Free PDF. You also join the Renvo Life newsletter. We'll email you the link after you confirm.
Not medical advice.
Read the label first
The formula only works with the right number from the label.
- Magnesium: use the "Magnesium" line on the Supplement Facts panel. NIH explains it "declares the amount of elemental magnesium in the product, not the weight of the entire magnesium-containing compound". A taurate bottle that says "1,500 mg" on the front has 120 mg of magnesium per 3 capsules. See label math.
- Protein: use protein per serving and the serving size, then check servings per container. Calories per 20 g of protein are worth a glance too. In the toolkit's ranking they vary a lot between foods.
- Blends: on magnesium labels, check the brackets for oxide (buffered glycinate check).
A tub or bar of your own, priced from the label, goes in the supplement cost per serving calculator.
Two guides, one bundle
The Magnesium Decoder covers label math, form cards, the buffered-glycinate check, an honest evidence meter, and 30 products by cost per 100 mg. It comes with printables and an Excel tracker. Protein on a Small Appetite ranks 40 protein foods by cost per 20 g and has 32 easy recipes with at least 20 g of protein each. It also has a 7-day low-appetite plan at about $6.40 a day in food, a shake and bar guide, trackers and a spreadsheet. Neither guide tells you what or how much to take or eat. That's for your doctor, pharmacist or clinician.
Studios, if the routine isn't only food and a bottle
The formula above prices magnesium and protein. It does not price a sauna or cold plunge session. For that, the studio pages quote each business's own site, checked 21 Oct 2026, and label any paid Featured spot. Wellness centers (compression, infrared sauna, massage and other listed services) are a separate directory.
Austin studios · Denver studios · Chicago studios · New York studios · All studio cities · Wellness centers
FAQ
How do I calculate cost per serving?
Price divided by servings per container. For a fairer comparison, use cost per unit: price divided by (servings times amount per serving), then times 100 mg for magnesium, or times 20 g for protein.
What's the cheapest protein per 20 g?
In the toolkit's ranking, dry lentils at $0.45 and large eggs at $0.60 (BLS September 2026 averages and dated US receipts).
What's in the $9 bundle?
The Magnesium Decoder and the GLP-1 protein toolkit: two PDFs, two spreadsheets and printables. Bought separately they cost $14.
Do the guides tell me how much to take or eat?
No. They compare labels, prices and recipes. Your clinician sets any targets.
Just want one guide? The Magnesium Decoder, $7 on Payhip Anzeige / Werbung (paid link) The GLP-1 protein toolkit, $7 on Payhip Anzeige / Werbung (paid link) Or get both for $9 Anzeige / Werbung (paid link).
Related: Magnesium cost per dose compared · magnesium cost per 100 mg calculator · Elemental magnesium label math · Magnesium glycinate vs citrate · GLP-1 protein toolkit · The Magnesium Decoder
Earlier in this series: buffered glycinate check · threonate: what the price buys · premium vs budget
Sources: NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals; BLS September 2026 US city average prices and dated US store receipts, as used in the GLP-1 protein toolkit; brand web stores and the NIH Dietary Supplement Label Database, checked 21 Oct 2026. Full citations are in the two guides. No brand paid to appear. Payhip buttons are labelled Anzeige because they go to guides Renvo Life sells.
Health disclaimer. Not medical advice. This is a shopping and label guide. It doesn't diagnose, treat or recommend doses, and makes no promises of results. Check with your doctor or pharmacist before starting a supplement, especially if you have kidney disease, are pregnant, or take prescription medicines. For protein: not reviewed by a dietitian. Your clinician sets your protein target, and you shouldn't change your medicine because of anything here.
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Last updated 21 Oct 2026