Formulation Science14 Oct 20265 min read

What are the different analytical methods used in cosmetic formulation?

Your cream passed its bench checks, then separated in stability storage, and the lab ran rheology afterwards to confirm what everyone could see. Used early, analytical methods are design tools, not post-mortems. This is what each one measures and the decision it should drive.

By CSL Analytical and formulation teams, Cosmetic Science Lab · Reviewed by Dr. Premalatha, Ph.D., Life Science, Regulatory Consultant

Evidence: Rico et al., Cosmetics 2024 reviewSeries: Part 1 of 2

Cosmetic laboratory bench with a dropper bottle and cream, with insets of a chromatography system, emulsion droplets under magnification, a viscometer spindle in cream and a microscope over pressed colour pans

Part 1What each analytical method measures (this article)
Part 2How to choose the right method at each stage

Quick answer

Analytical methods in cosmetic formulation fall into five groups: chromatographic, spectroscopic, interfacial, rheological and specialised [1].
Each method should drive a decision: accept a raw material, pick an emulsifier, rank prototypes or release a batch.
Three of the five development stages come before scale-up. That is where analytics can still change the formula.
No single technique characterises a product; nano, micro and macro data are needed together [1].

01The reactive analytics trap: why labs test after failure

Most labs test after something fails: a separated emulsion, a fragrance shift or a regulator's query. By then, testing only confirms the failure. A 2024 review in Cosmetics shows that analytical methods link a formula's microstructure to how it looks, feels and lasts [1]. The same instruments, used during design, flag the risk while the formula can still change. The review groups them into five categories, each answering a different formulation question:

**Table 1.** Analytical method categories and the decisions they inform
Category	Example methods	Decision it informs
Chromatographic	HPLC, LC-MS/MS, GC-MS	Accept or reject raw materials; confirm active content
Spectroscopic	Colorimetry, UV-Vis	Set colour specifications; catch colour drift
Interfacial	Surface and interfacial tension, contact angle	Choose the emulsifier system and level
Rheological	Flow curves, oscillation, temperature sweeps	Select thickener or polymer; tune texture
Specialised	Centrifugation, zeta potential, droplet sizing, electronic nose	Predict shelf life; keep fragrance consistent

Five development stages from raw materials to release. Stages 1 to 3 (raw materials, prototype, stability) are design stages where results change the formula; stages 4 and 5 (scale-up, release) confirm it. Each stage lists its methods and the decision it drives. — **Figure 1.** Analytical methods mapped to the five development stages. Results from stages 1 to 3 can still change the formula; stages 4 and 5 confirm it.

02Interfacial methods: choosing the emulsifier

Surface and interfacial tension show how well an emulsifier works at the oil–water boundary [1]. The lowest interfacial tension is not always best: systems right at the optimum formulation form unstable emulsions, and stability improves at a measured distance from it [1]. For particle-stabilised (Pickering) emulsions, contact angle governs whether fine particles can stabilise the interface [1].

How to use it

Screen emulsifier type and level with interfacial data before building full prototypes. It narrows the candidates early and cuts the number of stability samples you need.

03Chromatography: LC and GC for identity and purity

Chromatography separates a mixture so each ingredient can be identified and measured. Liquid chromatography (LC) and gas chromatography (GC) dominate cosmetic labs, paired with UV, diode-array (DAD) or mass spectrometry (MS) detectors [1].

**Table 2.** Liquid versus gas chromatography
	Liquid chromatography (HPLC, LC-MS/MS)	Gas chromatography (GC-FID, GC-MS)
Best suited to	Non-volatile or heat-sensitive compounds	Volatile, low-molecular-weight compounds
Typical targets	UV filters, antioxidants, preservatives, colourants	Fragrance components, regulated allergens, solvents
When to deploy	Raw-material intake, active stability, batch QC	Fragrance development, allergen checks, batch QC

Detector choice is a cost choice: UV and DAD suit routine work, while MS is needed for structure or trace levels [1]. Bio-based ingredients can also perform differently from fossil-derived ones [1], and intake chromatography is where you measure that difference before it reaches a prototype.

Two stacked HPLC chromatograms over 0 to 20 minutes: a reference standard with four peaks, and a stored sample where the active peak near 10 minutes is lower and a new degradant peak appears near 11.5 minutes. — **Figure 2.** HPLC comparison of a reference standard and a stored sample: a lower active peak and a new degradant peak. Illustrative schematic, not measured data.

04Rheology for emulsion stability and texture

Creams and lotions are dispersions. They hold still in the jar, then thin out on the skin [1], [7]. Rheology measures this, and it works best during design:

Flow curves: viscosity against shear rate, predicting pick-up, spreading and dispensing.
Oscillation: a storage modulus (G′) above the loss modulus (G″) signals a network that resists separation [1], [7].
Temperature sweeps: whether that structure collapses in heat during shipping or storage.

How to use it: a thicker continuous phase slows creaming, as Stokes' law predicts [1], [6]. Let rheology guide thickener and polymer choice, not just pass or fail a batch. Our case study on plant actives in O/W emulsions shows a temperature sweep predicting a 40 °C failure months ahead.

Log-log flow curve of viscosity against shear rate: a structured shear-thinning cream starts high at rest and falls steeply; a weakly structured lotion starts lower and falls gradually; guides mark rest in the jar, pick-up and spreading on skin. — **Figure 3.** Flow curves for a structured cream and a weakly structured lotion across the shear rates for rest, pick-up and spreading. Illustrative schematic, not measured data.

05Stability prediction: droplet size, zeta potential and centrifugation

Emulsions are thermodynamically unstable and will eventually cream, flocculate and separate [1], [6]. Shelf-life studies take months, so formulators stress prototypes with heat, light and centrifugation, then measure the change [4], [6].

**Table 3.** Stability methods and the design decision each informs
Method	What it reveals	Design decision
Droplet size	Larger droplets cream or settle faster	Adjust emulsifier level or homogenisation
Zeta potential	Surface charge that keeps droplets apart	Change emulsifier type or ionic content
Analytical centrifugation	Accelerated separation and size distribution	Rank prototypes before long-term storage

Droplet size distribution: a fresh prototype shows one narrow population near 2 micrometres; after heat or centrifugation stress the population broadens and a second population of large droplets appears near 15 micrometres, labelled coalescence risk. — **Figure 4.** Droplet size distribution before and after stress testing, showing a second population of large droplets. Illustrative schematic, not measured data.

Two cautions

Zeta potential often needs diluted samples, which can change the system being measured [1]. And accelerated results should be confirmed with real-time monitoring, as the stability guidelines advise [4], [5]. Run droplet sizing before and after each stress cycle to see coalescence early.

06Colorimetry, olfactometry and the electronic nose

Colorimetry turns colour into lightness, chroma and hue values, so "slightly darker" becomes a measured shift you can specify and track through stability storage [1].

GC-olfactometry (GC-O) splits the gas chromatograph's output between a detector and a trained assessor, linking each volatile to its odour [1]. Electronic noses use sensor arrays to check a whole scent profile quickly and affordably, which suits batch-to-batch consistency checks [1].

07Inside CSL's multi-scale analytical approach

CSL schedules analytics from raw-material intake, so each result feeds a design decision before scale-up. The same data supports the EU safety file and ISO 22716 GMP records [2], [3]. Cosmetic QC testing still matters, but it should confirm a formula that analytics have already shaped. Our analytical bioscience lab runs the chromatography and characterisation work.

Next: choosing the right method at each stage

Part 2 gives the decision framework, cost tiers and regulatory checklist: How to choose analytical methods at each stage of development.

08Questions readers ask

Which analytical method should come first in cosmetic formulation?

Chromatography at raw-material intake. It confirms identity and purity before an ingredient reaches a prototype.

Can rheology predict emulsion stability?

Partly. Flow and oscillation data show whether the structure resists separation, but they should be confirmed with stability testing.

Is accelerated stability testing enough?

No. It ranks prototypes quickly, but real-time monitoring is advisable to confirm shelf life.

Do I need every analytical method for every product?

No. Match each method to a formulation question. A simple toner needs far less than a pigmented sunscreen emulsion.

Want analytics that shape the formula?

We plan the method set from raw-material intake to release, so each result changes a decision before scale-up.

Testing services Talk to the CSL team

09References

Rico F, Mazabel A, Egurrola G, Pulido J, Barrios N, Marquez R, García J. Meta-analysis and analytical methods in cosmetics formulation: a review. Cosmetics, 2024; 11(1): 1. doi:10.3390/cosmetics11010001
Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products. EUR-Lex
ISO 22716:2007 Cosmetics — Good Manufacturing Practices (GMP) — Guidelines on Good Manufacturing Practices. ISO
Colipa (now Cosmetics Europe) and CTFA. Guidelines on stability testing of cosmetic products. March 2004. Cosmetics Europe PDF
ISO/TR 18811:2018 Cosmetics — Guidelines on the stability testing of cosmetic products. ISO
McClements DJ. Critical review of techniques and methodologies for characterization of emulsion stability. Critical Reviews in Food Science and Nutrition, 2007; 47(7): 611–649. PubMed
Tadros TF. Rheology of Dispersions: Principles and Applications. Weinheim: Wiley-VCH, 2010. Wiley-VCH

CSL

CSL Analytical and formulation teamsCosmetic Science Lab · Reviewed by Dr. Premalatha, Ph.D., Life Science, Regulatory Consultant · Last reviewed 14 Oct 2026Analytical chemistry and characterisation

Update log