Why Marine Collagen Powder Goes Cloudy in Some Liquids

Nothing has gone wrong. If your marine collagen powder has turned your drink milky or hazy, that is a normal optical effect caused by how hydrolysed peptides behave in solution — not a sign of contamination, degradation or a poor-quality product. The same powder can look crystal clear in one drink and opaque in another depending on three variables: temperature, pH and concentration.

What turbidity actually is

Turbidity is light scattering. When peptide chains in solution form loose aggregates large enough to deflect a beam of light, the liquid looks cloudy. Below that threshold, it looks clear. The peptides are present in both cases — you just can't see them when they stay dispersed as individual molecules.

Hydrolysed collagen is not a simple salt dissolving into ions. It is a mixture of peptides of varying chain lengths, and those chains interact with each other and with water molecules in ways that change depending on conditions.

Why marine collagen behaves differently from bovine

Molecular weight is the main reason. Bovine collagen peptides — Type I and III, derived from hides — are generally reported in the literature as falling in the 3,000–8,000 dalton range after hydrolysis. Marine collagen peptides, derived from fish skin and scales, tend to be smaller: commonly in the 500–2,000 dalton range, sometimes lower. Smaller peptides stay dispersed more readily at low concentrations, which is why marine collagen often looks clearer than bovine at the same serving size in warm water.

But smaller peptides are also more sensitive to pH changes. Their charge state shifts more sharply as acidity changes, which is why marine collagen can go noticeably cloudier than bovine in the same acidic drink — orange juice, for instance, or sparkling water with a squeeze of lemon.

The three variables

Temperature

Heat increases the kinetic energy of peptides in solution, which keeps them moving and dispersed. Cold slows that movement, allowing peptides to cluster. Mix marine collagen into cold water — particularly water below 10°C — and you are more likely to see haze than if you use water at 40°C or above. This is reversible. Warm the drink and the haze usually clears.

pH

At a peptide's isoelectric point — the pH at which its net electrical charge is zero — electrostatic repulsion between molecules drops to a minimum, so they aggregate. For collagen peptides the isoelectric point varies depending on peptide composition and molecular weight but tends to fall broadly in the neutral range, which means neutral water can sit close to it. Mildly acidic drinks (pH 3–5, which covers most fruit juices and sparkling waters) shift peptides away from that isoelectric point, increase repulsion, and can either clear the haze or — at higher concentrations — intensify it, depending on whether you are above or below the aggregation threshold for those specific peptide sizes.

In practice: plain still water at room temperature tends to produce mild, stable haze. Strongly acidic drinks may produce more visible cloudiness at first but often clear with stirring. Alkaline drinks, such as some mineral waters above pH 8, can produce a finer, more uniform haze that persists.

Concentration

More peptides per millilitre means more opportunities for aggregation. Your full serving in 150ml looks cloudier than the same amount in 350ml, all else being equal. This is straightforward: the higher the peptide density, the more scattering events occur per unit of liquid.

Which liquids tend to run clear

Warm water (above 35°C) at moderate dilution is the most reliable for a clear result. Black tea and coffee work well — not because anything chemical is suppressing turbidity, but because the existing colour of the drink masks the haze entirely. Smoothies, juices and milk-based drinks do the same through opacity.

Cold still water and neutral-pH sparkling water are the most likely to show visible cloudiness. That is not a problem unless cloudiness bothers you aesthetically — the peptides are present and behaving the same way either way.

What it means for your routine

If you want a clear drink, use warm water and stir thoroughly before the liquid cools. If you are mixing into something cold or acidic, expect haze and consider it cosmetic. It does not indicate that the product has clumped, spoiled or lost anything.

One practical note: marine collagen contains fish. Our Marine Collagen Powder 250g is 100% hydrolysed collagen from wild-caught North Atlantic fish and is not suitable for anyone with a fish or shellfish allergy or intolerance. If you are deciding between formats or sources, the guide on whether to choose bovine or marine collagen covers the structural differences in more detail. If you would rather avoid fish altogether, our Pure Bovine Collagen Powder is derived from the hides of grass-fed EU cattle and is not fish-derived.

Cloudiness, then, is physics — not a fault. The peptides are doing exactly what peptides do when you change the temperature, acidity or density of their environment. Understanding that removes the guesswork and lets you choose a mixing method that suits how you want the drink to look.