Take a fish oil capsule out of the jar and roll it between your fingers. It’s shiny, a bit squishy, gone in one swallow. You’d never guess how much fuss goes into making one.
Lena didn’t either. She’s an invented founder, though you’ll meet plenty like her, about to launch a vitamin D supplement. She thought the hard part would be the branding. Then she got on a call with a contract manufacturer like Vita Plus Inter, heard words like “fill migration” and “rotary dies,” and realised she’d better learn how softgels actually get made before agreeing to anything.
The shell, and what you’re allowed to put inside it
A softgel is a single sealed capsule. The outside is a soft, flexible shell. The inside is a liquid or a paste, almost always an oil, or a vitamin mixed into oil.
Most shells are made from gelatin, water, and glycerin. The glycerin keeps the shell bendy, so it doesn’t crack. Vegan brands go a different route, with plant-based shells built on modified starch and carrageenan, which comes from seaweed.
What surprised Lena was the rule about fills. Anything watery is basically off the table. Water creeps into the shell and makes it go soft and lumpy, so softgels stick to oils, oily suspensions, and thick pastes. Her vitamin D, dissolved in oil, was fine. A water-based extract wouldn’t have been.
Before anything gets mixed
Every ingredient gets tested when it arrives at the factory. Is it what the supplier says it is? Is it clean? In the US, this isn’t optional. Supplement makers have to follow the FDA’s manufacturing rules for dietary supplements, known as 21 CFR Part 111, and checking incoming materials is a big part of them.
Two tanks, two jobs
Then the factory gets busy on two fronts at once.
One tank cooks the shell. The ingredients are heated and stirred, usually under vacuum to pull the air bubbles out, until the mix turns thick and glossy, roughly like warm honey. There’s real skill in this. If it’s too stiff, it won’t spread into even sheets. If it’s too thin, you get flimsy capsules that split. When it’s right, it’s kept warm until the machine is ready.
The other tank mixes the fill. Every ingredient is weighed and blended so each capsule carries the same dose. For Lena’s product, that’s a big deal, because vitamin D goes in at a tiny amount spread through a lot of carrier oil. Mix it badly, and one capsule gets too much while the next gets hardly any. The fill also has to pump smoothly, so sometimes the texture or temperature gets nudged until it behaves.
Where the capsule is born
Most softgels come off something called a rotary die machine. The basic design is from the 1930s, and it’s still the workhorse of the industry.
Think of two rolling pins with little capsule-shaped pockets carved into them, turning towards each other. The warm gel is spread into two thin ribbons that feed between them. Just as the ribbons meet, a measured squirt of fill shoots in between. The pins press the edges together and cut the capsule out, all in one go, thousands of times a minute on a big line.
Swap the pins, and you swap the shape: round, oval, oblong, even a little fish shape if you’re feeling playful. Lena picked a small oval. Easier to swallow, she reckoned, and she was right.
Then everyone waits
New softgels are floppy and wet. First they tumble in big rotating drums that knock off surface moisture. Then they’re laid out on trays in dry, cool rooms and left until the shells firm up.
It’s slow, and that’s the point. Factories that rush it end up with capsules that clump together in the bottle or start leaking three months into someone’s shelf life. Ask any manufacturer about their drying process. Their answer tells you a lot.
Spotting the duds, which is where the cameras come in
After drying, the capsules are checked for cracks, leaks, air bubbles, bad seals, odd colours and wrong sizes. Lab tests look at weight, how much fill is inside, and whether the capsule breaks down the way it should.
For a long time the visual part was done by people, staring at trays of capsules under bright lights for hours. You can imagine how well that holds up at four in the afternoon. These days a lot of factories use automated cameras that snap a picture of every single softgel and reject the bad ones. Vita Plus Inter, for one, says it runs a fully automated visual inspection system with a manual re-check afterwards.
More and more, the software behind those cameras is AI. The models learn from thousands of photos of good and faulty capsules, and they get good at catching the stuff older systems miss, like a hairline gap in a seal or a bubble you’d need a magnifying glass to see. It’s the same thing happening in drinks, cosmetics, and food, from AI vision on filling lines right through to the packing room. Nobody’s quality team is out of a job. They just get a much sharper first pass, plus a log of every reject that makes it far easier to trace a problem back to its batch.
Into the bottle
The survivors go into bottles or blister packs that keep out damp, heat and light. The label carries the name, ingredients, batch number and expiry date. Even here, the robots are creeping in: AI-driven packaging automation now checks labels, seals and capsule counts as products fly past.
What Lena asked before she signed
Her first question was about certificates. Not the logos on the website, the actual documents. She also learned something that catches out a lot of first-time founders: “FDA-registered” just means the factory is on the FDA’s books. It doesn’t mean the FDA approved the product. In the US, supplements don’t get approved before they go on sale.
After that, she wanted to know how inspection works, whether by camera, by hand or both, and what happens to the rejects. Could they help her tweak the formula? Did they do plant-based shells as well as gelatin? Then the money side: minimum order, lead time, and what the quote actually covered.
A full-service softgel manufacturing service can handle the whole lot, from formula to finished bottle, which is a lifesaver for a small brand without its own lab. Vita Plus Inter, for example, lists minimum softgel orders of 1,000 to 3,000 units, low enough for a startup to test the market without betting the house. Lena still got three quotes and had everything put in writing. Not because anyone seemed dodgy. It’s just what you do.
Worth remembering
That little golden capsule went through testing, cooking, mixing, pressing, a long sit in a drying room and a camera inspection before it reached your cupboard. Skip any of those properly and it shows, sometimes months later. If you’re thinking of launching your own supplement, find a manufacturer who’ll happily walk you through every step and show you the paperwork to back it up.
Related: How Better Clinical Notes Improve Continuity of Care
