Skincare Serum OEM & Private Label Manufacturing

Formulation is only half the problem

A serum can pass every lab test and still fail in market. The usual causes are predictable:

• Viscosity drift — a formula thickened with a single gum thins over three months and starts to run off the dropper.
• pH excursion — actives such as L-ascorbic acid require a pH below 3.5 to remain effective and above 3.0 to remain tolerable; drifting outside that window loses both efficacy and stability.
• Oxidation — vitamin C and retinol formulas darken when oxygen enters the pack, which is a packaging problem as much as a formula one.
• Preservative challenge — a formula that passes micro at pilot scale can fail at production scale if water activity or pH shifted during scale-up.

That is why we develop the formula and the pack together. A 15 ml dropper bottle allows more headspace and more air ingress than a 30 ml airless pump, and the difference shows up as colour change at month six, not at release.

Standard production range

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Why fill accuracy is worth asking about

At 30 ml, a 3% overfill is 0.9 ml per unit — invisible on one bottle, worth around USD 900 on a 30,000-piece run. Conversely an underfill is a labelling violation in most markets, because the declared net content must be met on average across the batch. We fill by weight rather than volume and check hourly, which is the only approach that holds tolerance across a shift.

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The trade-off that catches brands out

A glass dropper bottle is the cheapest and most recognisable format, and it is the wrong choice for an oxidation-sensitive formula. Every time the cap comes off, the headspace exchanges with room air. A 15% L-ascorbic acid serum in a dropper will typically darken noticeably within three to four months of opening, which generates exactly the kind of review a new brand cannot afford.

An airless pump costs roughly 30–50% more per unit on the component alone. For a formula containing retinol, vitamin C or a delicate peptide, that premium buys shelf life and colour stability — and it is far cheaper than reformulating to a more stable but less marketable active level.

Ampoules are a channel decision, not just a pack

Single-use ampoules remove the preservative burden almost entirely and signal "treatment" to the buyer. They also cost more per millilitre, generate packaging waste, and require a filling line with different tolerances. Ampoules suit professional channels, travel retail and gift sets far better than a mass e-commerce listing.

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The questions this table answers

"Can we do 20% vitamin C?" Yes, but only in a pack that excludes oxygen, and only with a pH below 3.5 — which many consumers find stinging. Most commercial 15% products trade a little efficacy for tolerance.

"Why not 20% niacinamide?" Because the dose-response curve flattens around 5% and irritation rises. Above 10% the formula is harder to sell on claim and no easier to justify on cost.

"Can we combine retinol and vitamin C?" Not in one aqueous formula at effective levels. The pH windows do not overlap. Separate products, or separate times of day, are the honest answer.

What else is customisable

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What we decline

We decline briefs that specify a concentration with no tolerance for the formula being unstable. If the marketing plan requires 20% L-ascorbic acid in a clear dropper bottle on a 24-month shelf claim, the honest answer is that it will not hold — and no reputable formulator should say otherwise.

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Where the money goes

A finished 30 ml serum breaks down roughly as: primary pack 30–45%, formula 15–25%, carton and labelling 10–15%, filling and QC 10–15%, export packing and freight 5–10%. Two consequences matter commercially.

First, the pack is the negotiation lever, not the active. Moving from an airless pump to a dropper can reduce unit cost by 30% or more on the component — and it changes what formula you can sell. Second, fill volume is a pricing decision: a 15 ml dropper and a 30 ml dropper share almost the same component cost, so the smaller unit carries a much higher cost per millilitre. That is why 15 ml exists as a trial or travel format, not as a volume product.

Sampling and development cost

Library-formula samples are charged at cost and credited against the bulk order. Bespoke formulation carries a development fee that is credited once production passes 20,000 pieces; the fee covers lab time and a stability run, both of which are real costs regardless of eventual volume.

Timing reality

25–30 working days starts from signed artwork and received deposit. The variable that most often slips is pack availability: airless pumps and glass droppers in non-standard finishes are frequently 3–5 weeks lead-time items on their own. If launch date is fixed, confirm pack stock before approving artwork.

The checkpoints that predict market performance

1. 1Accelerated stability — 40°C/75% RH for three months, with pH, viscosity and colour logged at each timepoint. This is the test that catches separation before it reaches a customer.
2. 2Pack compatibility — the formula held in the production pack, not a generic container. Pump elastomers, dropper bulbs and liner adhesives all interact with fragrance and actives.
3. 3Preservative efficacy — challenge testing against the organisms your market's standard requires. Passing micro limits is not the same as passing a challenge test.
4. 4Fill weight verification — hourly by weight, with a batch record. Declared net content must be met on average, not per unit.
5. 5Micro release — every batch held until results clear, with retained samples kept past shipment.

Documents available with each shipment

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Colour drift is the complaint you will hear first

On a serum, colour change is the earliest visible failure and the one customers report. It has two usual causes: oxidation of an active, or a fragrance component reacting with the container. Both are predictable in an accelerated run and both are expensive to discover after launch.

1. 1Do you fill by weight or by volume? Weight holds tolerance as product temperature changes during a run. Volume does not. This is a one-sentence question with a very revealing answer.
2. 2Was the formula tested in the actual pack? Stability in a generic jar tells you nothing about a pump's elastomer or a dropper bulb's plasticiser.
3. 3What is the pH of the finished product, and how is it checked? Every active has a pH window. A supplier who cannot state the specification has not locked the formula.
4. 4Can I see the accelerated stability photos at each timepoint? Pass/fail summaries hide colour drift, which is what customers actually complain about.
5. 5Is the preservative system challenge-tested? Passing microbial limits is not the same test. A challenge test is what predicts whether the product survives consumer use.
6. 6What is the pack lead time, separately from the fill lead time? Airless pumps and specialty droppers are routinely the critical path on serum projects.
7. 7Who writes the CPSR, and can you supply the inputs? The assessment is issued by a qualified assessor; the inputs come from the factory. Confirm who provides what before you promise a launch date.

Red flags

• A formula quoted without asking about the pack.
• Vitamin C or retinol offered in a clear dropper bottle with a 24-month shelf claim.
• No pack compatibility test, or a test run in a generic container.
• Fill tolerance quoted as a percentage of volume rather than verified by weight.
• Stability data "available on request" but never actually produced.

Building a full range

This page covers one category only. Brands assembling a complete line usually pair it with Face Cream OEM and Acne Patch OEM. MOQ, lead times and material options for every category we run sit on the OEM/ODM service page.