Buoy vs. Ultima: Products That Competing for the Same Job

Most comparison posts put Buoy and Ultima side by side as if they’re two flavors of the same product category. They’re not. One is a drop-based additive meant to be squeezed into whatever you’re already drinking, several times a day. The other is a single-serve mixed powder drink meant to be dosed once, like a sports drink. Comparing them on a single “which has more sodium” line hides that structural difference — so this post pulls both companies’ own label numbers and shows what each product is actually built to do.

The label data, side by side

Buoy Electrolyte Drops (per serving = 1 squeeze, ~1.5 mL):

• Sodium: ~29 mg
• Potassium: ~14 mg
• Chloride: ~61 mg
• Magnesium: ~1 mg
• Calcium: ~1 mg
• Sugar: 0 g
• Suggested use: 4–7 servings spread across the day, added to any beverage (coffee, water, tea)

Ultima Replenisher (per serving = 1 scoop/stickpack, mixed into 16 oz water):

• Sodium: 55 mg
• Potassium: 250 mg
• Magnesium: 100 mg (25% DV)
• Calcium: 6% DV
• Chloride: 4% DV
• Sugar: 0 g, 0 calories

The ingredient sourcing differs too: Buoy draws its minerals from a proprietary sea-mineral blend plus what it markets as 87+ trace minerals, while Ultima uses individually dosed compounds — magnesium citrate, potassium phosphate, potassium aspartate, and sodium chloride — so each electrolyte’s amount is independently formulated rather than riding along in a natural mineral complex.

Why you can’t normalize these to the same chart

With Liquid I.V. or LMNT, you can normalize both to milligrams per liter because both are mixed to a specified volume. Buoy breaks that model on purpose — it’s designed to be squeezed into an unspecified beverage, at an unspecified final volume, multiple times a day. Forcing a per-liter number onto Buoy would manufacture a precision the product doesn’t claim to have. So instead, the fairer comparison is: one full day of Buoy’s recommended use vs. one single serving of Ultima.

	Buoy (daily total, 4–7 servings)	Ultima (single 16 oz serving)
Sodium	~116–203 mg	55 mg
Potassium	~56–98 mg	250 mg
Magnesium	~4–7 mg	100 mg

This produces a genuinely counterintuitive result that generic comparison content misses: across a full day of recommended use, Buoy actually delivers more total sodium than a single Ultima serving — but Ultima’s single serving delivers roughly 3–4x more potassium and around 15–20x more magnesium than a full day of Buoy. The two products aren’t scaled versions of each other; they’re solving different deficiency profiles. Buoy is closer to a sodium micro-dosing strategy, while Ultima is built around magnesium and potassium sufficiency, with sodium treated as the minor player.

The mechanism gap: magnesium dosing

This is the detail worth dwelling on. Magnesium is a cofactor in ATP production and protein synthesis, and typical adult intake shortfalls (a well-documented issue in Western diets) tend to run in the tens-of-milligrams range per day — which is exactly the range Buoy’s entire daily dose occupies. Ultima’s 100 mg per serving is large enough to represent a meaningful fraction of the 400–420 mg RDA for adult men (310–320 mg for women) in a single drink. If magnesium repletion is the actual goal, Buoy’s trace amount isn’t going to move that needle in any single day of normal use, while Ultima’s dose is large enough to matter — though also large enough that multiple servings could approach the threshold where magnesium citrate causes GI upset, which several reviewers have flagged as a real-world side effect of Ultima specifically.

Scenario-based verdict (not a single winner)

• You want to passively raise your baseline electrolyte intake throughout the day without a “drink a whole sports drink” moment: Buoy’s format is built for exactly this — it disappears into coffee, tea, or water you’re already drinking.
• You need meaningful magnesium or potassium replacement (heavy sweating, keto adaptation, magnesium-poor diet): Ultima’s per-serving doses are large enough to be physiologically relevant; Buoy’s aren’t, even across a full day of recommended servings.
• You specifically want sodium without committing to a full mixed drink each time: Buoy edges out a single Ultima serving on cumulative daily sodium, which is a genuinely underreported point in most comparisons.
• You want zero ambiguity about what you’re getting per serving: Ultima’s fixed-dilution, fixed-serving format gives you a real number to work from; Buoy’s “squeeze for as long as it takes to say Buoy” dosing instruction is inherently variable.

What neither company emphasizes

Buoy’s marketing leans on “87+ trace minerals,” but the label data shows the five electrolytes that matter for hydration (sodium, potassium, chloride, magnesium, calcium) are present in genuinely small absolute amounts — the trace-mineral count is a real ingredient story, not a hydration-dose story. Ultima’s marketing leans on “all 6 electrolytes,” which is accurate, but the sodium-to-potassium ratio (roughly 1:4.5) is inverted relative to what’s typically recommended for sweat replacement (closer to 2:1 sodium-to-potassium), meaning Ultima is not positioned as a heavy-sweat recovery drink despite living in the same retail aisle as products that are.

Sources: Buoy Electrolyte Drops label data via Amazon product Q&A and manufacturer ingredient listing (justaddbuoy.com); Ultima Replenisher nutrition facts panel via manufacturer retail listings (Natural Healthy Concepts, Metro Market, Kroger) and Amazon product listings.