If you're developing a softgel skincare product, you've probably heard this rule: the fill must be 100% oil‑based. No water. No water‑based actives. No hydrosols.
This isn't a marketing preference — it's a structural requirement. Here's why.
1. The Capsule Shell Is Water‑Sensitive
Softgel shells are made from gelatin or plant‑based alternatives like HPMC (hydroxypropyl methylcellulose). Both materials are hydrophilic — they absorb water. When the fill inside contains even a small amount of water, that moisture migrates into the shell over time.
The result？ The capsule becomes soft, sticky, and deformed. It may stick to other capsules, lose its shape, or even leak. What was once a firm, elegant pearl becomes a sticky mess — and no consumer wants to touch that.
In short: water softens the shell. Oil keeps it firm.
2. Moisture Triggers Microbial Growth
Water is life — including for bacteria, yeast, and mould. A water‑containing fill would require a robust preservative system to stay safe. But preservatives are tricky in softgels. They can interact with the shell, affect stability, and limit your clean‑label claims.
Oil‑based fills, on the other hand, have very low water activity. Microorganisms can't thrive. This means no preservatives are needed — a major advantage for brands targeting natural or minimalist positioning.
3. Oil Protects Sensitive Actives
Many potent skincare actives — retinol, vitamin C (oil‑soluble derivatives), CoQ10, idebenone, essential fatty acids — are oil‑soluble and prone to oxidation when exposed to air and light. Softgels provide an oxygen‑free, light‑blocking environment. But if water were present, it could accelerate degradation or cause phase separation.
Oil‑based systems keep everything miscible, stable, and potent from production to application.
4. Capsule Integrity Depends on a Dry Fill
During encapsulation, the fill must have a specific viscosity and low moisture content to form a perfect seal. Water‑based ingredients can interfere with the sealing process, leading to weak welds, leaking, or inconsistent shapes. Oil flows predictably, seals cleanly, and ensures every capsule meets quality standards.
5. What About Water‑Soluble Actives？
If your star ingredient is water‑soluble (like hyaluronic acid, niacinamide, or vitamin C in its pure L‑ascorbic form), you have two options:
Use oil‑soluble derivatives (e.g., tetrahexyldecyl ascorbate for vitamin C, or oil‑compatible versions of niacinamide).
Or choose a different format — ampoules, vials, or blister‑packed liquids — designed to hold water‑based formulas.
We specialise in oil‑based softgels, but we also offer other formats for water‑based serums and essences. The key is choosing the right delivery system for each ingredient.
What This Means for Your Brand
If you're set on softgel encapsulation, your formula must be built entirely around oils, esters, and oil‑soluble actives. This isn't a limitation — it's an advantage.
Oil‑based serums are deeply nourishing, barrier‑friendly, and increasingly popular with consumers who understand that healthy skin needs lipids. Softgels make them clean, portable, and preservative‑free.
And if you have a water‑based hero ingredient, we can guide you toward the best format — whether that's a different capsule, a blister pack, or a traditional dropper bottle.
We Handle the Oil‑Based Challenge for You
Our GMP‑certified factory in Guangzhou specialises in custom oil‑based softgel formulations. Our R&D team works with you to select compatible actives, stabilise blends, and create a product that stays perfect from factory to customer.
We offer full customisation: shell type, capsule shape, colour, and packaging. And we're happy to advise on ingredient compatibility before you commit.
Ready to formulate your oil‑based softgel？
Send us your ingredient wishlist or target benefits — we'll recommend a compatible formula and provide a custom quote within 24 hours.
Your brand. Our expertise. Made in Guangzhou.
Visit us — see how oil and shell come together perfectly.