What Is Polyhydroxybutyrate?
Polyhydroxybutyrate, often shortened to PHB, is a naturally occurring biopolymer made of repeating units of 3-hydroxybutyric acid. Certain soil and marine bacteria create it as an energy reserve, and today it is produced on a larger scale through the fermentation of renewable feedstocks such as corn or sugarcane. After fermentation the polymer is separated from the bacterial cells, purified, and ground into a fine, uniform powder suited for cosmetic use.
First studied in the 1980s as a biodegradable alternative to conventional plastics, PHB caught the eye of the beauty industry once researchers noticed its mild polishing action and its ability to leave skin feeling soft. By the mid-2000s formulators had begun adding it to scrubs and cleansers as a naturally sourced replacement for plastic microbeads. You can now spot PHB in facial and body exfoliators, cream cleansers, clay or gel masks, daily polishing powders, and even some anti-aging lotions where a touch of gentle buffing is desired.
Polyhydroxybutyrate’s Cosmetic Benefits/Uses
In skin care formulas PHB serves two key functions that bring both sensory and performance perks:
- Abrasive: The tiny spherical particles provide a mild physical exfoliation that lifts away dull surface cells, smooths rough patches, and promotes a fresher looking complexion without scratching the skin. As a biodegradable material it offers a planet-friendly alternative to traditional plastic exfoliants.
- Skin Conditioning: Beyond polishing, PHB deposits a soft, lightweight film that helps the skin feel silkier and better hydrated, enhancing the overall after-feel of creams, lotions, and rinse-off products.
Who Can Use Polyhydroxybutyrate
Thanks to its gentle exfoliating action Polyhydroxybutyrate suits most skin types, including normal, oily, dry and combination. Sensitive skin generally tolerates it well because the particles are smooth and rounded, yet anyone with active eczema, open cuts or inflamed breakouts may prefer to skip physical polishers until the skin is calm.
PHB is produced by fermenting plant-derived sugars with microorganisms, then separating and purifying the polymer. No animal-derived raw materials or by-products are involved, so it is considered vegan and vegetarian friendly.
The ingredient itself has no known issues for women who are pregnant or breastfeeding, but personal circumstances vary. This content is not medical advice; expectant or nursing mothers should review any skincare routine with a qualified physician to be extra safe.
Unlike alpha hydroxy acids or retinoids, Polyhydroxybutyrate does not make skin more prone to sunburn. Normal daytime sun protection practices are still advised, but no additional precautions are needed specifically because of PHB.
Potential Side Effects/Adverse Reactions
Responses to topical Polyhydroxybutyrate differ from person to person. The effects below are possible yet uncommon when the ingredient is used at typical cosmetic levels in a well-formulated product.
- Mild redness or stinging if the skin is scrubbed too vigorously or is already irritated
- Transient dryness or tightness from removing too many surface cells during prolonged polishing
- Micro-abrasions on very thin or compromised skin when excessive pressure is applied
- Contact allergy presenting as itching or small bumps, though documented cases are rare
- Heightened sensitivity when combined with strong chemical exfoliants or aggressive cleansing tools
If any of these reactions occur stop using the product and seek advice from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1 / 5
Polyhydroxybutyrate particles are solid, water-insoluble spheres that rinse cleanly off the skin without leaving an oily or waxy residue. They do not melt into pores or form a film that could trap sebum, so they have very little potential to clog follicles. A small rating of 1 is given because any physical scrub can, in theory, push debris into pores if it is rubbed aggressively, though this issue is technique related rather than an inherent property of the ingredient.
Suitable for acne-prone or breakout-prone skin when used with light pressure and in a formula that is otherwise non-comedogenic.
As a biodegradable polymer, PHB does not accumulate on the skin over time, further lowering clogging risk.
Summary
Polyhydroxybutyrate acts mainly as a mild abrasive and secondary skin-conditioning agent. Its smooth micro-spheres gently lift away dead surface cells to reveal fresher skin, while a subtle, breathable film leaves the complexion feeling soft and silky. These benefits come from the polymer’s uniform particle size and its ability to glide over the skin without sharp edges.
Although PHB is still a niche ingredient compared with mainstream exfoliants like silica or jojoba beads, its eco-friendly origin and microplastic-free status are driving steady interest among green beauty brands and consumers looking for gentler options.
Current safety data show PHB to be low-risk for irritation or allergy in most users. As with any new skincare ingredient it is wise to patch test a product before full-face use to make sure your individual skin responds well.