What Is 3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer?
3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer is a biodegradable polymer made from two naturally occurring building blocks, 3-hydroxybutyrate and 3-hydroxyhexanoate. Most suppliers obtain it through biofermentation, where specially selected microorganisms feed on renewable plant oils and convert them into long chains of polyhydroxyalkanoates. Once the ferment is complete, the polymer is separated, purified and milled into a fine powder that can be blended into cosmetic bases.
The material first gained attention in the 1990s as a sustainable alternative to petroleum-based plastics. Its eco-friendly profile later attracted cosmetic chemists looking for natural exfoliating particles to replace synthetic microbeads. Today you will most often spot it in facial scrubs, body polishes, cleansing powders, clarifying masks and lip or hand scrubs. Because the particles can be manufactured in different sizes and shapes, formulators can tailor how mild or vigorous the exfoliation feels on the skin.
3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer’s Cosmetic Benefits/Uses
This ingredient serves a single, straightforward purpose in skincare formulas.
Abrasive: When dispersed in a cream, gel or powder cleanser the polymer functions as a gentle physical exfoliant. The tiny biodegradable granules help lift away dead surface cells, excess oil and residual makeup without scratching or damaging healthy skin. Regular use can leave the complexion feeling smoother and looking brighter while also improving the way serums or moisturizers absorb.
Who Can Use 3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer
This biodegradable exfoliant suits most skin types, especially normal, combination and oily skin that benefit from help sloughing off built-up surface cells. People with very sensitive or thin skin can still use it when the granules are ultra-fine and gentle pressure is applied, but anyone experiencing active eczema, raw acne lesions or rosacea flare-ups may find any physical scrub too stimulating until the skin has settled.
The polymer is produced by microorganisms that ferment plant oils so it contains no animal-derived material, making it appropriate for vegans and vegetarians.
No data suggest the ingredient poses a risk during pregnancy or breastfeeding because it sits on the skin briefly then rinses away rather than penetrating deeply. This is not medical advice and anyone who is pregnant or nursing should let a doctor review their full skincare lineup to be safe.
It does not increase photosensitivity, and unlike some fruit seed scrubs the particles are smooth enough that they do not leave microscopic splinters behind.
Potential Side Effects/Adverse Reactions
Responses to topical 3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer differ from person to person. The points below list potential side effects that could occur even though most users will not experience them when the product is well formulated and used as directed.
- Mechanical irritation – vigorous rubbing or using a scrub too often can leave the skin feeling raw or looking pink
- Micro-tears – pressing hard with coarse particles may create tiny breaks in the surface barrier that lead to stinging when other products are applied
- Worsening of inflammatory skin conditions – eczema psoriasis or cystic acne can flare if physical exfoliation is introduced at the wrong time
- Contact dermatitis – an uncommon allergic reaction triggered by residual fermentation by-products or other ingredients in the formula
- Barrier disruption when combined with other exfoliants – pairing a scrub with strong acids or retinoids can over-exfoliate and cause dryness and peeling
If any undesirable reaction develops stop using the product and consult a healthcare professional or dermatologist for guidance.
Comedogenic Rating
Rating: 0/5
3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer is a solid particulate that sits on the skin surface only long enough to buff away dead cells then washes cleanly down the drain. It is not an oil or wax, does not melt into pores and shows no evidence of causing blockages in clinical or anecdotal reports. For these reasons it earns a non-comedogenic score of 0.
Suitable for acne-prone or breakout-prone skin.
Keep in mind that overall pore-clogging potential also depends on the emulsion, oils or butters used alongside the particles, so always consider the full formula.
Summary
3-Hydroxybutyrate/3-Hydroxyhexanoate Copolymer is a biodegradable polymer primarily valued as a gentle physical exfoliant. Its smooth plant-derived granules polish away dull surface cells which helps skin feel soft, look brighter and absorb leave-on products more evenly.
The ingredient gained traction after plastic microbeads were phased out and while it is not yet a household name it is showing up more often in eco-minded scrubs, cleansing powders and masks.
Safety data are reassuring since the polymer is inert, non-penetrating and has very low irritation and allergy risk when used correctly. As with any new product a quick patch test is still wise to be on the safe side.