You’ve probably seen them lined up in shops. Skin-lightening creams with names that sound like miracles in a jar: Radiant Boost, Glow White, Luminous Clear. But have you ever wondered what’s really inside them? That’s what Tebello Sekoati, a Chemical Technology student at the National University of Lesotho (NUL), set out to find.
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Brought to you by NUL Innovation Hub [Where Academia Meets Industry] & MILCO [a store that sells only Lesotho products at Sefika Complex]. MILCO was founded by NUL Innovation Hub

Her mission? To find out whether the locally made cosmetic products people use every day contain a controversial ingredient called hydroquinone; and if so, how much of it.

“I wanted to know what we are really putting on our skin,” she said. “Some products claim to be herbal or natural, but the chemistry doesn’t always agree!”

She was supervised by Dr Ntlama Lesotho.

Sekoati first heard about hydroquinone in one of her lectures on Organic Chemistry. It’s a small molecule with a big, famous (or infamous) reputation. On one hand, it helps with dark spots caused by the sun or scars.

On the other, scientists warn that long-term use can cause skin damage and even cancer. “People want quick results,” she said, “but sometimes what helps you glow today might hurt your skin tomorrow.”

With that in mind, she began her detective work in local markets and beauty shops around Maseru. She bought a mix of body lotions, brightening creams, petroleum jellies, and lip guards.

The same ones that ordinary people use every day.

Each product was carefully labelled and packed for testing back in the NUL laboratory.

To uncover their chemical secrets, she used two advanced methods: Thin Layer Chromatography (TLC) and High-Performance Liquid Chromatography (HPLC). “TLC tells you if hydroquinone is there at all,” she explained. “HPLC is like a microscope for molecules. It tells you exactly how much is there.”

But before she could test anything, she had to prepare her lab setup with precision.

She mixed sulfuric acid solutions, carefully adding acid to water, “never the other way around,” she laughed. She weighed out her samples on a delicate analytical balance. She also prepared hydroquinone standards to build what chemists call a calibration curve.

These standards are like reference points that help calculate unknown concentrations. In her lab book, she had scribbled a reminder: “Accuracy is everything. One wrong drop and your data is gone!”

She heated the samples gently using a heating mantle until they dissolved, filtered each through Whatman filter paper, and recorded everything meticulously. Then came the moment of truth.

One by one, she placed the samples into the UV-Vis Spectrophotometer, a machine that shines light through the solution to see how much is absorbed.

Hydroquinone has a unique light pattern, so by comparing the readings to her calibration curve, she could work out its concentration.

When the results appeared on the screen, she couldn’t believe it.

Every single sample contained hydroquinone. “I was surprised,” she said. “Even the ones that didn’t mention hydroquinone on the label had it hiding inside!”

The concentrations ranged from 0.019% to 0.8675%, all below the 2% limit set by international health authorities. “So technically, they’re within limits,” she smiled, “but that doesn’t mean they’re safe if used every day for years.”

She explained that chronic exposure can still cause skin irritation, darkening, or worse. The real problem, she said, is that Lesotho currently has no official body regulating cosmetic ingredients.

“Anyone can make and sell a skin-lightening cream,” she said. “It’s not always malicious; some small manufacturers just don’t have the tools or knowledge to test their products.”

She also found that some brands labelled themselves as “herbal” or “organic” while still containing chemical lighteners. “It’s like calling a soda healthy because it has lemon flavor,” she joked.

Her findings show that while people are buying these products for confidence and beauty, they might be exposing themselves to hidden risks.

Of course, science is never perfect.

Sekoati learned that things like instrument calibration, temperature, or tiny differences in how samples are prepared can affect the results. To make sure her data was solid, she repeated her tests and averaged the readings.

“Sometimes the spectrophotometer just didn’t want to cooperate,” she said with a laugh. “It’s not about stopping people from wanting to look good,” she said. “It’s about making sure beauty doesn’t come at the cost of health.”
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Brought to you by NUL Innovation Hub [Where Academia Meets Industry] & MILCO [a store that sells only Lesotho products at Sefika Complex]. MILCO was founded by NUL Innovation Hub